Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.

NOTE: This diagnostic assumes the following:

The battery is completely charged.
The engine cranking speed is acceptable.
There is adequate fuel in the fuel tank.

Crank the engine for up to 15 s.
Verify that DTC P0117, P0118, P0122, P0123, P018C, P018D, P0201, P0202, P0203, P0204, P0222, P0223, P0231, P0232, P023F, P025A, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0335, P0336, P0513, P0562, P0563, P0601, P0602, P0603, P0604, P0606, P0628, P0629, P062F, P0633, P0685, P0689, P0690, P1516, P1631, P1682, P16F3, P2101, P2119 or P2610 are not set.
- If any of the DTCs are set
  Refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- If none of the DTCs are set
Ignition ON
Verify the security indicator on the instrument cluster illuminates momentarily.
- If the security indicator stays ON or is flashing
  Review the Diagnostic Trouble Code (DTC) List - Vehicle , for Immobilizer system DTCs. For additional information, refer to Immobilizer Description and Operation .
- If the security indicator does not stay ON and is not flashing
Verify the scan tool Engine Speed parameter displays greater than 0 RPM while cranking the engine.
- If 0 RPM
  Refer to DTC P0335 or P0336 .
- If greater than 0 RPM
Install the EN 36012-A Ignition System Diagnostic Harness to the spark plug boots.
NOTE: It may be necessary to secure the EN 36012-A Ignition System Diagnostic Harness to the spark plug boots with electrical tape.
Connect the EL 26792 HEI Spark Tester between the boot of a spark plug wire and ground.
Connect the remaining wires to the appropriate cylinders.
Verify the spark tester sparks while cranking the engine.
NOTE:
- Perform the spark test on at least 3 of the cylinders.
- An erratic or weak spark is considered a no spark condition.
- If the spark tester does not spark
  Refer to Electronic Ignition System Diagnosis .
- If the spark tester sparks
Ignition OFF, all accessories OFF, install the CH 48027 Digital Pressure Gauge.
Ignition ON.
Command the Fuel Pump Enable On several times with a scan tool.
NOTE:
- If the engine is too hot, high fuel pressure readings may result due to hot soak fuel boiling. Allow the engine coolant temperature to cool to less than 60°C (150°F) before attempting to verify fuel pressure.
- The Fuel Pump Enable may need to be commanded On a few times in order to obtain the highest possible fuel pressure.
- Additional DTCs may set when using the fuel pump output control.
Verify the fuel pressure is between 345-650 kPa (50-94 PSI) with the fuel pump running.
- If not within the specified range
  Refer to Fuel System Diagnosis .
- If within the specified range
Verify that the fuel pressure, after the fuel pump has turned OFF, decreases to less than 600 kPa (87 PSI) and does not decrease greater than 34 kPa (5 PSI) in 1 minute.
- If not within the specified range
  Refer to Fuel System Diagnosis .
- If within the specified range
Ignition OFF, disconnect the harness connector at a Q17 Fuel Injector.
Connect the J 34730-2C Injector Test Lamp between the control circuit and the ignition voltage circuit.
Verify the injector test lamp flashes while cranking the engine.
- If the injector test lamp does not flash
  Refer to Fuel Injector Diagnosis .
- If the injector test lamp flashes
Verify the conditions listed below do not exist:
- Air intake duct to the throttle body collapsed
- Air filter or air intake system restricted
- Gas or coolant fouled spark plugs. Refer to Spark Plug Inspection .
- A skewed manifold absolute pressure (MAP) sensor.
- A skewed engine coolant temperature (ECT) sensor.
- Exhaust system restricted. Refer to Restricted Exhaust (except 2.0L Diesel LUZ) .
- Contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- An engine mechanical condition, for example, worn timing belt or low compression. Refer to Symptoms - Engine Mechanical .
- If a condition exists
  Repair as necessary.
- If no conditions exist
All OK.