Circuit/System Verification
IMPORTANT:
This diagnostic assumes the following system voltage levels are adequate for starter motor operation.
- The battery is completely charged. Refer to Battery Inspection/Test .
- The engine cranking speed is acceptable. Refer to Engine Cranks Slowly .
- There is adequate fuel in the fuel tank.
- Engine cranking for 15 seconds, observe the DTC information with a scan tool. DTCs P0117, P0118, P0122, P0123, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0335, P0336, P0337, P0351, P0352, P0562, P0563, P0601, P0604, P0605, P0628, P0629, P1610, P1611, P1628 or P1629 should not set.
- If any DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Ignition ON, observe the scan tool Theft Deterrent parameter. The reading should display Disabled.
- If Enabled is displayed, refer to Symptoms - Theft Deterrent .
- Ignition OFF, disconnect the fuel pump relay.
- Connect a J 26792 to the boot of a spark plug wire of a cylinder and ground.
- Engine cranking, verify the spark tester sparks.
- If there is no spark, refer to Electronic Ignition (EI) System Diagnosis .
- Ignition OFF, install the fuel pump relay.
- Ignition ON, command the fuel pump ON with a scan tool. You should hear the fuel pump turn ON.
- If the fuel pump does not turn ON, refer to Fuel Pump Electrical Circuit Diagnosis .
- Ignition OFF, install the J 34730-1A . See Special Tools . Refer to Fuel Pressure Gage Installation and Removal .
- The fuel pump may need to be commanded ON a few times, in order to obtain the highest possible fuel pressure.
- Do NOT start the engine for this test.
- Ignition ON, command the fuel pump ON with a scan tool. The fuel pressure should be between 262-303 kPa (38-44 psi)
.
- If not within the specified range, refer to Fuel System Diagnosis .
- Verify the following conditions do not exist:
- Collapsed air intake duct to the throttle body
- Restricted air filter element
- Spark plugs for being gas or coolant fouled-Refer to Spark Plug Inspection .
- A skewed manifold absolute pressure (MAP) sensor-Refer to Altitude Versus Barometric Pressure .
- A skewed engine coolant temperature (ECT) sensor-Refer to Temperature Versus Resistance .
- Exhaust system restricted-Refer to Restricted Exhaust .
- Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- Engine mechanical condition, for example, worn timing belt or low compression-Refer to Engine Compression Test or Symptoms - Engine Mechanical .
- If you find any of the above conditions, repair as necessary.
IMPORTANT:
An erratic or weak spark is considered a no spark condition.
IMPORTANT: