Gasoline Direct Injection

Ford is adding gasoline Direct Injection (DI) to many of its engines for improved fuel economy, performance and emissions. Most engines will also incorporate a turbocharger when they go to DI, however, some engines will not. Engines with turbo charging are designated as GTDI (Gasoline Turbo Direct Injection) and engine without turbo charging are designated GDI (Gasoline Direct Injection).

The fuel systems for both of these variants are very similar. The only difference is that the GDI engine does not have the turbo controls that consist of the Turbocharger, Wastegate Control Valve, Compressor Bypass Valve and the sensor that contains the Throttle Inlet Pressure Sensor (TCB-A) and Throttle Charge Temperature Sensor (CACT)

Ford's first GTDI engine was introduced in the 2010 MY. The 3.5 L GTDI engine was based off the 3.5L IVCT engine used in the Taurus, Edge, etc. The GTDI version was introduced in the 2010 MY Ford Flex, Lincoln MKR (CUV), Taurus and Lincoln MKS (sedan).

The PCM for the GTDI engine controls the following sensors and actuators:

Outputs/Actuators: Electronic Throttle Control, Variable Cam Timing (Intake only), Wastegate Control Valve, Compressor Bypass Valve, Ignition timing, Fuel injectors (Direct Injection), Fuel Rail Pressure Control Valve

Inputs/Sensors: MAP, Manifold Charge Temp, Throttle Inlet Pressure, Throttle Charge Temp, Intake Air Temp, BARO, Cylinder Head Temp, Cam & Throttle positions, Engine Speed, Fuel Rail Pressure, UEGO (front, control), HEGO (rear fuel trim)

For the 2011 MY, 3.5L/3.7L engine was upgraded from ICVT (Intake-only Variable Cam Timing) to TIVCT (Twin Independent Variable Cam Timing. The 3.5L GTDI engine in the F-150 is based off this upgraded engine (3.5L GTDI TIVCT). The DI and turbo controls, however, are unchanged.

For the 2011 MY, the Explorer will be available with a 2.0L GTDI engine with TIVCT. For 2012 MY, it is also available in the Edge. The DI and turbo controls are similar to the 3.5L GTDI with the exception that there is only one turbocharger.

For the 2012 MY, the Focus will be available with a 2.0L GDI engine with TIVCT. The controls are similar to the 2.0L GTDI engine. The only difference is that the GDI engine does not have the turbo controls that consist of the Turbocharger, Wastegate Control Valve, Compressor Bypass Valve and the sensor that contains the Throttle Inlet Pressure Sensor (TCB-A) and Throttle Charge Temperature Sensor (CACT)

Because GDI engine controls and OBD are a subset of the GDTI engine controls and OBD, they will all be described in this chapter.

Intake Air Temperature 1 Sensor (IAT1) 

The Intake Air Temperature 1 sensor (also called Air Charge Temperature) is used for the inference of ambient temperature for several PCM strategy features. In previous designs, the Intake Air Temperature 1 sensor was physically integrated with the Mass Air Flow (MAF) sensor. In this design, the Intake Air Temperature 1 sensor is a stand-alone sensor and is mounted near the air cleaner.

DTCs	P0112 Intake Air Temperature Sensor 1 Circuit Low (Bank 1) P0113 Intake Air Temperature Sensor 1 Circuit High (Bank 1)
Monitor execution	continuous
Monitor Sequence	none
Sensors OK	not applicable
Monitoring Duration	5 seconds to register a malfunction

P0112 IAT1 voltage < 0.244 volts P0113 IAT1 voltage > 4.96 volts

DTCs	P0114 Intake Air Temperature Sensor 1 Intermittent/Erratic (Bank 1)
Monitor execution	continuous
Monitor Sequence	none
Sensors OK	not applicable
Monitoring Duration	counts intermittent events per trip

10 intermittent out-of-range events per driving cycle

Charge Air Cooler Temperature Sensor (CACT) 

The Charge Air Cooler Temperature sensor (also known as Throttle Charge Temperature) refines the estimate of air flow rate through the throttle.

DTCs	P007C Charge Air Cooler Temperature Sensor Circuit Low (Bank 1) P007D Charge Air Cooler Temperature Sensor Circuit High (Bank 1)
Monitor execution	continuous
Monitor Sequence	none
Sensors OK	not applicable
Monitoring Duration	5 seconds to register a malfunction

P007C CACT voltage < 0.244 volts P007D CACT voltage > 4.96 volts

Intake Air Temperature 2 Sensor (IAT2) 

The Intake Air Temperature 2 sensor (also known as Manifold Charge Temperature) is mounted to the intake manifold and is used to compute cylinder air charge and provide input for various spark control functions. It is integrated with the intake manifold pressure sensor.

DTCs	P0097 Intake Air Temperature Sensor 2 Circuit Low (Bank 1) P0098 Intake Air Temperature Sensor 2 Circuit High (Bank 1)
Monitor execution	Continuous
Monitor Sequence	None
Sensors OK	not applicable
Monitoring Duration	5 seconds to register a malfunction

P0097 IAT2 voltage < 0.244 volts P0098 IAT2 voltage > 4.96 volts

Volts	A/D counts in PCM	Temperature, degrees F
4.89	1001	-40
4.86	994	-31
4.81	983	-22
4.74	970	-13
4.66	954	-4
4.56	934	5
4.45	910	14
4.30	880	23
4.14	846	32
3.95	807	41
3.73	764	50
3.50	717	59
3.26	666	68
3.00	614	77
2.74	561	86
2.48	508	95
1.99	407	113
1.77	361	122
1.56	319	131
1.37	280	140
1.20	246	149
1.05	215	158
0.92	188	167
0.80	165	176
0.70	144	185
0.61	126	194
0.54	110	203
0.47	96	212
0.41	85	221
0.36	74	230
0.32	65	239
0.28	57	248
0.25	51	257
0.22	45	266
0.19	40	275
0.17	35	284
0.15	31	293
0.14	28	302

IAT1, CACT, IAT2 Key-Up Correlation Check 

Once the IAT1, CACT, IAT2 are confirmed to be in-range, the key-up correlation test compares the three temperatures on key-up after a long period off key-off time (6 hours). The three-way correlation test is run only once per power-up.

After a long key-off period, the three temperature sensors are expected to report nearly the same temperature. The exception to this is when a block heater is used. Block heater use can cause these three air temperature sensors to widely differ from each other. To detect if an engine coolant heater is active we compare Cylinder Head Temperature (CHT) to Transmission Fluid Temperature (TFT). A significant temperature difference (10°F) indicates block heater activity.

The IAT, CACT, and IAT2 are mounted along the engine air intake system.

• The IAT is mounted in the engine air inlet (near air cleaner).
• The CACT is mounted near the throttle inlet.
• The IAT2 is mounted inside the intake manifold.

If the sensors all agree, no malfunction is indicated and the test is complete. Specifically, the three way check compares 3 sensor pairings. All three pairings must correlate to pass this test.

• IAT and CACT agree within a tolerance (±30°F) and
• CACT and IAT2 agree within a tolerance (±30°F) and
• IAT2 and IAT agree within a tolerance (±30°F).

Case 1  At least two correlation pairings are within tolerance (±30°F). All sensors pass.

Case 2  One correlation pairing is within tolerance (±30°F). Those two sensors that correlate pass, the third sensor is flagged as faulted.

Case 3  Zero correlation pairings are within tolerance (±30°F). P00CE Intake Air Temperature Measurement System - Multiple Sensor Correlation

DTCs	P0111 Intake Air Temperature Sensor 1 Circuit Range/Performance (Bank 1) P007B Charge Air Cooler Temperature Sensor Circuit Range/Performance (Bank 1) P0096 Intake Air Temperature Sensor 2 Circuit Range/Performance (Bank 1) P00CE Intake Air Temperature Measurement System - Multiple Sensor Correlation
Monitor execution	Once per driving cycle, at start-up
Monitor Sequence	None
Sensors OK	ECT/CHT, IAT1, CACT, IAT2, TFT
Monitoring Duration	Immediate

Entry Condition	Minimum	Maximum
Engine off (soak) time	6 hours
CHT - TFT at start (block heater inferred)		+ 10 °F

CHT at least 10°F hotter than TFT means block heater detected.

IAT1, CACT, IAT2 Out of Range Hot Check 

The IAT1, CACT, IAT2 are all checked for maximum expected temperature readings during a steady state driving condition. When parked at hot ambient temperatures or after heavy load operation, these temperatures can climb to unusually high temperatures thus the "too hot" check is not done at those conditions.

DTCs	P0111 Intake Air Temperature Sensor 1 Circuit Range/Performance (Bank 1) P007B Charge Air Cooler Temperature Sensor Circuit Range/Performance (Bank 1) P0096 Intake Air Temperature Sensor 2 Circuit Range/Performance (Bank 1)
Monitor execution	Continuous
Monitor Sequence	None
Sensors OK	ECT/CHT, IAT, VSS
Monitoring Duration	250 seconds to register a malfunction

Entry condition	Minimum	Maximum
Vehicle speed	40 mph
Time above minimum vehicle speed (if driving req'd)	5 min
For IAT1, Load below a maximum load threshold	1.0

P0111 IAT1 > 150°F P007B CACT > 220°F P0096 IAT2 > 240°F

Barometric Pressure Sensor (BARO) 

The Barometric Pressure Sensor (BARO) is used to directly measure barometric pressure and for exhaust back pressure estimation. (Exhaust back pressure influences speed density based air charge computation.) The BARO sensor is directly mounted to the PCM circuit board.

The BARO sensor has a high accuracy operating range of 60 to 115 kPa (17.7 to 34.0 "Hg) and a full operating range of 7.6 to 121.6 kPa. The voltage is electrically clipped between 0.3 and 4.8 volts.

A P2228 or P2229 DTC indicates that either the sensor is electrically faulted or the sensed barometric pressure is outside the normal operating range.

Vout=Vref * (0.007895 * Pressure (in kPa)
Volts	Pressure, kPa	Pressure, Inches Hg
0.3	7.6	2.2
0.5	12.7	3.8
2.638	60	17.7
4.54	115	34.0
4.75	120.3	35.5
4.8	121.6	35.9

DTCs	P2228 Barometric Pressure Circuit Low P2229 Barometric Pressure Circuit High
Monitor execution	continuous
Monitor Sequence	None
Sensors OK	not applicable
Monitoring Duration	5 seconds to register a malfunction

P2228 BP < 2.0 volts (above 15, 000 ft altitude) P2229 BP > 4.4 volts (below -1, 000 ft altitude)

Turbocharger Boost Sensor A (TCB-A) 

The Turbocharger Boost Sensor A (also known as Throttle Inlet Pressure (TIP)) is the feedback sensor for turbo boost control. Boost control algorithm computes desired boost from operating conditions and adjusts the pneumatically-controlled boost pressure limit to achieve that desired boost pressure. TCB-A is also used to compute air flow rate through the throttle independently of the primary air charge computation for torque monitoring (and intake manifold leak detection).

The TCB-A sensor is physically integrated with the Charge Air Cooler Temperature Sensor. The boost sensor has a specified range of 20 to 300 kPa. The voltage is electrically clipped between 0.3 to 4.8 volts,

Vout=(Vref / 5) * (0.0146428 * Pressure (in kPa) + 0.1072)
Volts	Pressure, kPa	Pressure, Inches Hg
0.3	13.16	3.89
0.4	20	5.91
0.986	60.0	17.72
2.157	140	41.34
3.329	220.0	64.97
4.5	300	88.59
4.8	320.49	94.64

DTCs	P0237 Turbocharger/Supercharger Boost Sensor A Circuit Low P0238 Turbocharger/Supercharger Boost Sensor A Circuit High
Monitor execution	continuous
Monitor Sequence	None
Sensors OK	not applicable
Monitoring Duration	5 seconds to register a malfunction

P0237 TCB-A voltage < 0.19 volts P0238 TCB_A voltage > 4.88 volts

DTCs	P025E Turbocharger/Supercharger Boost Sensor "A" Intermittent/Erratic
Monitor execution	continuous
Monitor Sequence	none
Sensors OK	not applicable
Monitoring Duration	counts intermittent events per trip

10 intermittent out-of-range events per driving cycle

Intake Manifold Pressure (MAP) Sensor 

The Manifold Absolute Pressure (MAP) sensor is used for the Speed Density air charge calculation.

The MAP sensor is physically integrated with the Intake Air Temperature 2 sensor. The MAP sensor has a specified range of 10 to 200 kPa. The voltage is electrically clipped between 0.3 to 4.8 volts,

Vout=Vref * (0.0044736 * Pressure (in kPa) + 0.035263)
Volts	Pressure, kPa	Pressure, Inches Hg
0.3	5.53	1.63
0.40	10.0	2.95
1.630	65.0	19.19
2.301	95.0	28.05
3.643	155.0	45.77
4.65	200.0	59.06
4.8	206.71	61.04

DTCs	P0107 Manifold Absolute Pressure/BARO Sensor Low P0108 Manifold Absolute Pressure/BARO Sensor High
Monitor execution	continuous
Monitor Sequence	None
Sensors OK	not applicable
Monitoring Duration	5 seconds to register a malfunction

P0107 MAP voltage < 0.19 volts P0108 MAP voltage > 0.4.88 volts

DTCs	P0109 Manifold Absolute Pressure/BARO Sensor Intermittent
Monitor execution	continuous
Monitor Sequence	none
Sensors OK	not applicable
Monitoring Duration	counts intermittent events per trip

10 intermittent out-of-range events per driving cycle

BARO, TCB-A, MAP Sensor 3-Way Correlation Check at Key-Up 

At key-up BARO, TCB-A, and MAP are compared. If any two agree and one does not, that sensor is declared faulted.

DTCs	P2227 P0236 P0106 Barometric Pressure Circuit Range/Performance
Monitor execution	At key-up
Monitor Sequence	None
Sensors OK	BP, MAP, TIP
Monitoring Duration	0.2 seconds

Entry Condition	Minimum	Maximum
Engine off (soak) time	10 seconds
Battery Voltage	6.75 volts

|TCB-A - MAP| < 2.72"Hg |BARO - MAP| < 2.03"Hg |BARO - TCB-A| < 2.14"Hg

BARO, TCB-A and TCB-A, MAP Sensor 2-Way Correlation Check 

Should a BARO, TCB-A, or MAP sensor pass the key-on test but become faulted during operation, two air pressure sensor correlation check are made.

• At low engine air flows no turbocharger boost is commanded and BARO should be very close to TCB-A.
• In certain operation regions, MAP can be estimated from TCB-A, throttle angle, and engine speed (a.k.a. speed-throttle).

These two correlations are then used to infer if any of the three air pressure sensors are faulted

DTCs	P2227 Barometric Pressure Sensor "A" Circuit Range/Performance P0236 Turbocharger/Supercharger Boost Sensor "A" Circuit Range/Performance P0106 Barometric Pressure Circuit Range/Performance
Monitor execution	Continuous
Monitor Sequence	None
Sensors OK	BP, TIP, MAP
Monitoring Duration	10 seconds

Entry Condition	Minimum	Maximum
Low TP		4.0°
Low Engine rpm		1500 rpm

pass (|BARO - TCB-A| < 5.5"Hg) AND (|MAP - Estimated MAP| < 3.5"Hg) P2227 (|BARO - TCB-A| > 5.5"Hg) AND (|MAP - Estimated MAP| < 1.8"Hg) P0106 (|BARO - TCB-A| < 1.8"Hg) AND (|MAP - Estimated MAP| > 3.5"Hg) P0236 (if none of above conditions met)

Compressor Bypass Valve(s) 

The compressor bypass valve(s) is used to prevent backflow though the turbocharger compressors when the throttle is rapidly closed to avoid an undesirable audible noise. The high pressure downstream of the compressor bypasses the compressor as it travels upstream when the valve is open. In this application, two compressor bypass valves are used to establish a sufficient bypass flow rate. The compressor bypass valve(s) are checked for electrical faults.

DTCs	P0034 Turbocharger/Supercharger Bypass Valve "A" Control Circuit Low P0035 Turbocharger/Supercharger Bypass Valve "A" Control Circuit High P00C1 Turbocharger/Supercharger Bypass Valve "B" Control Circuit Low P00C2 Turbocharger/Supercharger Bypass Valve "B" Control Circuit High
Monitor Execution	Continuous
Monitor Sequence	None
Monitoring Duration	5 seconds

PCM smart driver hardware detects faults for circuit short to battery, short to ground, and open circuit. Fault status reported to PCM to set appropriate DTC.

Wastegate Pneumatic Solenoid Valve 

The wastegate (one per turbocharger) allows exhaust pressure to bypass the turbocharger's turbine, to control compressor speed (on the same shaft), and thus boost pressure. The wastegate controller is actually a mechanical-pneumatic boost pressure controller. Its boost pressure limit can be increased within a limited range by altering the pressure "seen" by the pneumatic actuator. The wastegates are only controlled indirectly by the PCM via the wastegate pneumatic solenoid.

A high pressure on the wastegate actuator's diaphragm tends to open the wastegate. The solenoid valve normally connects compressor out pressure (boost) to the wastegate actuator's diaphragm, resulting in the regulation of maximum boost pressure (to a constant value). Using the wastegate vent solenoid to partially vent (reduce) that control pressure increases the regulated maximum boost.

As the compressor outlet pressure increases, a pneumatically powered actuator opens each turbocharger wastegate to limit compressor outlet pressure. The wastegate pneumatic solenoid valve modulates that feedback pressure to increase the boost pressure limit. A duty cycle of 100% vents feedback thus eliminating any wastegate controlled boost limit. A duty cycle of 0% results in the base boost limit of approximately 5 psi gauge.

DTCs	P0245 Turbocharger/Supercharger Wastegate Solenoid A Low P0246 Turbocharger/Supercharger Wastegate Solenoid A High
Monitor Execution	Continuous
Monitor Sequence	None
Monitoring Duration	5 seconds

PCM smart driver hardware detects faults for circuit short to battery, short to ground, and open circuit. Fault status reported to PCM to set appropriate DTC.

Vacuum Actuated Wastegate System 

The 3.5L GTDI was introduced with a mechanical-pneumatic boost pressure controller as described in the previous section. Boost pressure is limited mechanically via a diaphragm and spring. Boost pressure can be increased within a limited range by controlling a wastegate pneumatic solenoid.

The 2.0L GTDI was introduced with a vacuum actuated wastegate. This permits control of the wastegate position at all engine conditions. The wastegate can be opened at some part load conditions to reduce the backpressure on the engine. This reduces pumping losses and improves efficiency and fuel economy. A vacuum sensor was added to improve the accuracy and robustness of the control system.

DTCs	P0245 Turbocharger/Supercharger Wastegate Solenoid A Low P0246 Turbocharger/Supercharger Wastegate Solenoid A High
Monitor Execution	Continuous
Monitor Sequence	None
Monitoring Duration	2 -3 seconds

PCM smart driver hardware detects faults for circuit short to battery, short to ground, and open circuit. Fault status reported to PCM to set appropriate DTC.

Under steady conditions, the control pressure error should be small. Control pressure lower than expected could indicate an air leak between wastegate canister and the wastegate solenoid, and insufficient source of vacuum, or that the wastegate solenoid is stuck off. Control pressure higher than expected could indicate that the wastegate solenoid is stuck on

DTCs	P1015 Wastegate Control Pressure Lower Than Expected P1016 Wastegate Control Pressure Lower Than Expected
Monitor Execution	Continuous
Sensors OK	No P100F, P1011, P1012, P1013, P0245, P0246 DTCs
Monitor Sequence	None
Monitoring Duration	5 Seconds

Entry Condition	Minimum	Maximum
Desired wastegate control pressure is stable: (desired pressure - expected pressure).		0.5 in Hg

P1015 - Wastegate control pressure error > 3 in Hg P1016 - Wastegate control pressure error > 5 in Hg

Wastegate Control Pressure Sensor 

The wastegate control pressure sensor is checked for opens, short and intermittents, P1012, P1013 and P1014.

DTCs	P1012 Wastegate Control Pressure Sensor Circuit Low P1013 Wastegate Control Pressure Sensor Circuit High P1014 Wastegate Control Pressure Sensor Circuit Intermittent/Erratic
Monitor Execution	Continuous
Monitor Sequence	None
Monitoring Duration	5 seconds

Vout=(Vref / 5) * (0.04399 * Pressure (in kPa) - 0.140)
Volts	Pressure, kPa	Pressure, Inches Hg
0.3	10.0	2.95
0.4	12.3	3.62
1.0	25.9	7.65
2.0	48.6	14.36
3.0	71.4	21.07
4.5	105.5	31.14
4.8	112.8	33.31

Entry Condition	Minimum	Maximum
none

P1012 - voltage < 0.20 V P1013 - voltage > 4.93 V P1014 - open or shorted > 10 events in a driving cycle

The wastegate control pressure sensor reading is checked at key-up using a four-way correlation check. If the wastegate control pressure sensor reading is higher or lower than the readings of the BARO, MAP, and TIP, a P100F is set. A P1011 is set if the wastegate control pressure is greater than BARO.

DTCs	P1011 Wastegate Control Pressure Sensor Circuit Range/Performance P100F Wastegate Control Pressure/BARO Correlation
Monitor Execution	Continuous
Monitor Sequence	None
Sensors OK	No P1012, P1013, P1011, P2228, P2229, P2227, P0236, P0106 DTCs.
Monitoring Duration	5 seconds

Entry Condition	Minimum	Maximum
Engine off time (P100F only)	20 sec

P100F - pressure error exceeds 2.5 in Hg P1011 - pressure exceeds BARO by > 3.0 in Hg

Boost Control 

The boost control system determines a desired boost. Active control occurs when the desired boost is above base boost where base boost is defined as that boost that results when the wastegate vent solenoid is not venting (circuit off).

The following conditions may result in underboost.

• One or more wastegates stuck open
• Large conduit leak between compressor and throttle

The following conditions may result in overboost.

• One or more wastegates stuck closed
• One or more control hoses leaking/disconnected between wastegate diaphragm and wastegate vent solenoid.
• Wastegate vent solenoid stuck in vent position
• Control hoses to wastegate vent solenoid swapped.
• Hose between boost volume and wastegate vent solenoid disconnected.
• Not-yet-detected Turbocharger Boost sensor in-range failure.

The boost control system computes a desired boost based on operating conditions. Via the wastegate pneumatic solenoid valve, it varies the boost pressure limit to achieve its desired boost level (measured by the TCB-A sensor). The air charge control regulates the throttle to control the intake manifold pressure (MAP).

DTCs	P0234 (Turbocharger/Supercharger A Overboost Condition)
Monitor Execution	continuous
Monitor Sequence	none
Sensors/Actuators OK	CBV, TCB-A, WGS, BARO
Monitoring Duration	5 seconds (up/down timer)

Entry Condition	Minimum	Maximum
Wastegate Duty Cycle		0.05

(Boost Pressure Desired - Boost Pressure Actual) > 4 psi

DTCs	P0299 (Turbocharger/Supercharger A Underboost Condition)
Monitor Execution	continuous
Monitor Sequence	none
Sensors/Actuators OK	CBV, TCB-A, WGS, BARO
Monitoring Duration	5 seconds (up/down timer)

Entry Condition	Minimum	Maximum
Wastegate Duty Cycle		0.05

(Boost Pressure Desired - Boost Pressure Actual) > 4 psi

Fuel Injectors, Gasoline Direct Injection 

Overview 

The Gasoline Direct Injection (GDI) system is similar to a Port Fuel Injection (PFI) system with the exception of an added high-pressure pump.

• An in-tank pump supplies 65 psi fuel to the high pressure, camshaft-driven pump.
• The PCM-controlled pump produces a selectable pressure in the fuel rail(s).
• On/off injectors meter the high pressure fuel directly into the cylinders.

Gasoline Direct Injection (GDI) injectors spray liquid fuel, under high pressure, directly in the cylinder when activated. The high pressure fuel is supplied to the injector by a common fuel rail. The desired fuel pressure is determined by the PCM. Fuel injector pulse width is based on actual fuel pressure which is measured by a pressure sensor in the common rail.

Injection typically occurs in the cylinder's intake and compression stroke. Under certain conditions, multiple injections can occur per cylinder event. Since injection pressure is variable, the fuel mass injected is a function of both fuel pressure and injector pulse width.

A typical PFI injector is activated by applying battery voltage to it. The GDI injector driver applies a high voltage (65 volts) to initially open the injector and then controls injector current to hold it open during injection.

Fuel Injectors 

A typical PFI injector is single side controlled by the PCM. The GDI injector has two wires per injector routed to the PCM. The injector high side goes to a PCM pin (or two pins) that are common between an injector pair. The PCM contains a smart driver that monitors and compares high side and low side injector currents to diagnose numerous faults. All injector fault modes, however, are mapped into a single DTC per injector.

A higher-than-battery-voltage supply (internally generated within the PCM) is used to open the injector and modulated battery voltage holds the injector open. The injector driver IC controls three transistor switches that apply the boost voltage and then modulate injector current. Should that full voltage be unavailable, the proper injector opening current may not be generated in the time required. This fault (P062D) is detected on a per cylinder basis and reported without specifying a particular cylinder.

DTCs	P0201 through P0206 (Cylinder x Injector Circuit) P062D Fuel Injector Driver Circuit Performance
Monitor execution	Continuous within entry conditions
Monitor Sequence	None
Monitoring Duration	10 seconds

Entry Condition	Minimum	Maximum
Battery Voltage	11.0 Volts

Fuel Volume Regulator 

The high pressure fuel pump raises Fuel Rail Pressure (FRP) to the desired level to support fuel injection requirements. Unlike Port Fuel Injection (PFI) systems, with Gasoline Direct Injection (GDI), the desired fuel rail pressure ranges widely over operating conditions.

The Fuel Volume Regulator is controlled to allow a desired fraction of the pump's full displacement (fuel volume) into the fuel rail. A fuel rail pressure control algorithm computes the required fraction of fuel pump volume to achieve the desired pressure. The high pressure fuel pump can only increase (and not reduce) fuel rail pressure. Fuel Injection is used to reduce fuel rail pressure.

The Fuel Volume Regulator (FVR) is a solenoid valve permanently mounted to the pump assembly. It selects one of two plumbing elements upstream of the pump chamber. The next figure shows the solenoid valve in the unpowered position.)

Solenoid State	Plumbing Element Selected
Un-powered	Flow Through (i.e. Check Valve Disabled)
Energized	Check Valve

The FVR control is done synchronous to the cam position on which the pump is mounted. The synchronous FVR control must take into account that the camshaft phasing is varied during engine operation for purposes of valve control.

The FVR solenoid coil may overheat and fail if constant battery voltage is applied. For that reason, the PCM is equipped with protections to prevent FVR damage due certain wiring faults.

The FVR is a two wire device (high and low side control) with both wires routed to the PCM. This means that either or both wires can generate the DTC(s).

DTCs	P0001 Fuel Volume Regulator Control Circuit / Open P0003 Fuel Volume Regulator Control Circuit Low P0004 Fuel Volume Regulator Control Circuit High
Monitor execution	continuous
Monitor Sequence	none
Sensors OK	none
Monitoring Duration	not applicable

Fuel Rail Pressure Sensor 

The fuel rail pressure control system uses the measured fuel rail pressure in a feedback control loop to achieve the desired fuel rail pressure. The fuel injection algorithm uses actual fuel rail pressure in its computation of fuel injector pulse width and fuel injection timing.

The Fuel Rail Pressure sensor is a gauge sensor. Its atmospheric reference hole is in the electrical connector. The fuel rail pressure sensor has a nominal range of 0 to 26 MPa (0 to 260 bar, 0 to 3770 psi). This pressure range is above the maximum intended operating pressure of 15 MPa and above the pressure relief valve setting of 19.4 MPa. The sensor voltage saturates at slightly above 0.2 and slightly below 4.8 volts.

Fuel rail pressure can develop a vacuum when the vehicle cools after running. Vacuums can be measured by the FPR gauge sensor as voltages near the 0.2 Volt limit.

FRP Sensor Transfer Function
FRP = -471.37 psi + (FRP_voltage / 5.0 volts) * 4713.73 psi
Volts	Pressure, MPa (gauge)	Pressure, psi (gauge)
4.80	27.95	4054
4.50	26	3771
3.50	19.5	2828
2.50	13.0	1885
1.50	6.5	943
0.50	0	0
0.20	-1.95	-283

DTCs	P0192 - Fuel Rail Pressure Sensor A Circuit Low P0193 - Fuel Rail Pressure Sensor A Circuit High
Monitor execution	Continuous
Monitor Sequence	none
Sensors OK	none
Monitoring Duration	5 seconds to register a malfunction

FRP voltage < 0.20 volts or FRP voltage > 4.80 volts

A fuel pressure sensor that is substantially in error results in a fuel system fault (too rich / too lean). If actual fuel rail pressure exceeds measured pressure, more fuel than that which would be expected is injected and vice versa. This fuel error would show up in the long term and short term fuel trim.

Fuel Rail Pressure Control 

Fuel rail pressure is maintained via:

• Feed-forward knowledge of pump command and injector fuel quantity and
• Feedback knowledge of sensed pressure.

A set point pressure is determined by engine operating conditions. If a pressure increase is desired, the fuel pump effective stroke is increased via FVR valve timing. Pressure decreases are analogous; however, without injection fuel rail pressure cannot be decreased. Acting alone, the pump can only increase pressure.

In theory, the PCM could exactly account for mass entering the rail via the pump and exiting the rail via the injectors, however, since both the pump timing and injector timing are constantly changing and interact, this is very difficult. Thus, the pump control performs fuel pressure control as a continuous process. It calculates average fuel mass over 720° (one engine cycle) and average fuel pressure over 240°. Control is executed at engine firing rate 240°.

For diagnostic purposes, fuel fractional pressure error is computed as a ratio of the pressure error over the desired pressure. This unitless ratio is then compared to thresholds to yield fuel pressure too low (P0087) or fuel pressure too high (P0088).

DTCs	P0087 (Fuel Rail Pressure Too Low) P0088 (Fuel Rail Pressure Too High)
Monitor execution	continuous
Monitor Sequence	P0087 and P0088 must complete before setting P00C6 or P053F
Sensors/Actuators OK	FLI, FRP, FVR,, Lift Pump
Monitoring Duration	not applicable

Entry Condition	Minimum	Maximum
High Pressure Pump Enabled	Enabled
Fuel level	15%
Injector Cut Off	No Injector Cut Off
Injection Volume / (720° Pump Volume / Number of Cylinders)	0.05	0.90
Engine Coolant Temperature	20°F	250°F
CSER Mode	Not in CSER

P0087: (Fuel_Pressure_Desired - Fuel_Pressure_Actual) / Fuel_Pressure_Desired > 0.25 P0088: - (Fuel_Pressure_Desired - Fuel_Pressure_Actual) / Fuel_Pressure_Desired > 0.25

Fuel Rail Pressure Control (Cranking) 

The engine is designed to start with a minimum required fuel injection pressure. If that minimum fuel injection pressure is not achieved before the first fuel injection, a fault is set.

DTCs	P00C6 (Fuel Rail Pressure Too Low - Engine Cranking)
Monitor execution	Minimum pressure met instantaneously once during cranking
Monitor Sequence	P0087 and P0088 must pass before setting P00C6 or P053F
Sensors/Actuators OK	FLI, FRP, FVR,, Lift Pump
Monitoring Duration	Minimum met instantaneously once during cranking

Entry Condition	Minimum	Maximum
Fuel Level	15%

Fuel_Pressure_Actual >= Fuel_Pressure_Desired

Fuel Rail Pressure Control (CSER) 

While not used in this first GTDI application, it is possible that during catalyst heating (CSSER) the fuel injection timing may be unique to this mode. In future cases, a two squirt injection may be used. One of those injection squirts would occur during the compression stroke. Compression injection is only allowed within a calibrated fuel pressure "window". The P053F detection monitors the time fraction within that fuel pressure window.

DTCs	P053F (Cold Start Fuel Pressure Control Performance)
Monitor execution	During CSER
Monitor Sequence	P0087 and P0088 must pass before setting P00C6 or P053F
Sensors/Actuators OK	FLI, FRP, FVR,, Lift Pump
Monitoring Duration	Entire CSER period

Entry Condition	Minimum	Maximum
Fuel Level	15%

Time in Fuel Injection Pressure Window / CSER Duration > 0.70 Fuel Injection Pressure Window defined as follows: Minimum Fuel Pressure to Support Desired Injection Mode <= Fuel Pressure Actual Fuel Pressure Actual <= Maximum Fuel Pressure to Support Desired Injection Mode