FixVault

Diagnostic procedure

DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 Remove all the spark plugs.
Inspect the spark plug condition.
Is the spark plug condition normal?
Yes Troubleshooting completed.
No Specific plug Is wet or covered with carbon: 
Go to the next step.
Specific plug looks grayish white: 
Go to Step 9.
All plugs are wet or covered with carbon: 
Go to Step 11.
All plugs look grayish white: 
Go to Step 19.
2 Is the spark plug wet/covered with carbon from engine oil? Yes Inspect all areas related to oil.
No Go to the next step.
3 Inspect the spark plugs for the following:
  • Cracked insulator
  • Heat range
  • Air gap
  • Worn electrode

Is the spark plug normal?
Yes Go to the next step.
No Replace the spark plug.
4 Inspect the compression pressure at the suspected malfunctioning cylinder.
Is the compression pressure correct?
(See COMPRESSION INSPECTION ).
Yes Go to the next step.
No Repair or replace the malfunctioning parts.
5 Install all the spark plugs.
Perform the spark test at the suspected malfunctioning cylinder.
Is a strong blue spark visible?
(Compare with normal cylinder).
Yes Go to the next step.
No Repair or replace the malfunctioning parts.
6 Access and monitor the FUEL_PRES PID.
Is the FUEL_PRES PID value within the specification?
(See USING THE WDS OR EQUIVALENT ).
Yes Inspect the suspected cylinders fuel injector for the following:
  • Open or short circuit in the fuel injector

(See FUEL INJECTOR INSPECTION ).
No Go to the next step.
7 Inspect the fuel pressure sensor.
(See FUEL PRESSURE SENSOR INSPECTION ).
Is the fuel pressure sensor normal?
Yes Go to the next step.
No Replace the delivery pipe.
8 Inspect the high pressure fuel pump.
(See HIGH PRESSURE FUEL PUMP INSPECTION ).
Is the high pressure fuel pump normal?
Yes Replace the delivery pipe.
Retest Step 6
If the FUEL_PRES PID indication is other that the specification, replace the high pressure fuel pump.
No Replace the high pressure fuel pump.
9 Inspect the spark plug for the following.
  • Heat range
  • Air gap

Is the spark plug normal?
Yes Go to the next step.
No Replace the spark plug.
10 Perform the KOER self-test function using the WDS or equivalent.
(See KOEO/KOER SELF TEST ).
Is the suspected cylinder injector circuit related DTC (P0201, P0202, P0203 or P0204) present?
Yes Go to appropriate the DTC test.
(See DTC TABLE ).
No Inspect the suspect cylinder fuel injector for the following:
11 Is the air cleaner element free of blockage? Yes Go to the next step.
No Replace the air cleaner element.
12 Perform the spark test.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION ).
Is a strong blue spark visible at each cylinder?
Yes Go to the next step.
No Repair or replace the malfunctioning parts.
13 Access and monitor the FUEL_PRES PID. Is the FUEL_PRES PID value within the specification?
(See USING THE WDS OR EQUIVALENT ).
Yes Go to step 16.
No Go to the next step.
14 Inspect the fuel pressure sensor.
(See FUEL PRESSURE SENSOR INSPECTION ).
Is the fuel pressure sensor normal?
Yes Go to the next step.
No Replace the delivery pipe.
15 Inspect the high pressure fuel pump.
(See HIGH PRESSURE FUEL PUMP INSPECTION ).
Is the high pressure fuel pump normal?
Yes Replace the delivery pipe.
Retest Step 13.
If the FUEL_PRES PID indication is other that the specification, replace the high pressure fuel pump.
No Replace the high pressure fuel pump.
16 Inspect the following PIDs:

Are the PIDs normal?
Yes Go to the next step.
No Repair or replace the malfunctioning parts.
17 Perform the purge control inspection.
(When engine can be started)
(See PURGE CONTROL SYSTEM INSPECTION ).
Is the purge control correct?
Yes Go to the next step.
No Repair or replace the malfunctioning parts.
18 Perform the compression inspection.
Is the compression correct?
Yes Inspect for clogging in the exhaust system.
No Repair or replace the malfunctioning parts.
19 When the engine cannot be started, inspect the intake-air system for air leakage.
When the engine can be started, perform the intake manifold vacuum inspection.
Is air sucked in from the intake-air system?
Yes Repair or replace the malfunctioning part.
No Go to the next step.
20 Access and monitor the FUEL_PRES PID. Is the FUEL_PRES PID value within the specification?
(See USING THE WDS OR EQUIVALENT ).
Yes Inspect for the following PIDs:
  • ECT
  • O2S11
  • O2S12
  • MAF

(See PCM INSPECTION ). Inspect the PCM ground condition.
No Go to the next step.
21 Is vehicle accelerate performance normally? Yes Go to the next step.
No Go to Step 13.
22 Inspect the fuel pressure sensor.
(See FUEL PRESSURE SENSOR INSPECTION ).
Is the fuel pressure sensor normal?
Yes Go to the next step.
No Replace the delivery pipe.
23 Replace the high pressure fuel pump.
Monitor FUEL_PRES PID.
Is the FUEL_PRES PID value within the specified?
(See USING THE WDS OR EQUIVALENT ).
Yes Troubleshooting is completed.
Go to Step 16.
No Inspect following PIDs.
  • ECT
  • O2S11
  • O2S12
  • MAF

(See USING THE WDS OR EQUIVALENT ). Inspect PCM ground condition.
24 Verify test results.
  • If normal, return to the diagnostic index to service any additional symptoms.
  • If a malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform the repair or diagnosis.
    • If the vehicle is repaired, troubleshooting is completed.
    • If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.