Circuit/System Verification
WARNING: This page is about a different car, the 2015 Chevrolet Trax and 2015 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
- This diagnostic assumes the following:
- The battery is completely charged.
- The engine cranking speed is acceptable.
- An engine that starts and stalls is considered to not run.
- Crank the engine for up to 15 s.
- Verify that DTC P0117, P0118, P0121, P0122, P0123, P0201, P0202, P0203, P0204, P0222, P0223, P0231, P0232, P023F, P0261, P0262, P0264, P0265. P0267, P0268, P0270, P0271, P0335, P0336, P0601, P0602, P0603, P0604, P0606, P062B, P062F, P0630, P0685, P0686, P0687, P0689, P0690, P1516, P1682, P16F3, P2101, P2119, P2135, P2176, P262B, or P2635 is not set.
- If any of DTCs are set
.
Refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- If none of the DTCs are set
- If any of DTCs are set
.
- Ignition ON.
- Verify that the immobilizer system indicator on the instrument cluster illuminates momentarily.
- If the indicator stays ON or is flashing
Review the Diagnostic Trouble Code (DTC) List - Vehicle , for immobilizer system DTCs. For more information concerning the immobilizer system, refer to Immobilizer Description and Operation .
- If the indicator does not stay ON and is not flashing
- If the indicator stays ON or is 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
- If 0 RPM
- Connect the EN 36012-A Ignition System Diagnostic Harness to the spark plug boots.
- 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.
- Perform the spark test on at least 3 of the cylinders.
- An erratic or weak spark is considered a no spark condition.
- Verify the spark tester sparks, while cranking the engine.
- If the spark tester does not spark
Refer to Electronic Ignition System Diagnosis .
- If the spark tester sparks
- If the spark tester does not spark
- Verify the fuel pump turns ON and OFF when commanding the Fuel Pump Relay On and Off with a scan tool.
- If the fuel pump does not turn ON and OFF
Refer to Fuel Pump Electrical Circuit Diagnosis (LUJ) .
- If the fuel pump turns ON and OFF
- If the fuel pump does not turn ON and OFF
- Ignition OFF, all accessories OFF, install a CH 48027 Digital Pressure Gauge.
- Ignition ON.
- The Fuel Pump Relay 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.
- Command the Fuel Pump Relay On several times with a scan tool.
- Verify the fuel pressure is between 276-345 kPa (40-50 PSI) with the fuel pump running.
- If not within the specified range
Refer to Fuel System Diagnosis (LUJ) .
- If within the specified range
- If not within the specified range
- Verify the fuel pressure does not decrease more than 34 kPa (5 PSI) in 1 minute.
- If not within the specified range
Refer to Fuel System Diagnosis (LUJ) .
- If within the specified range
- If not within the specified range
- Ignition OFF, disconnect the harness connector of a fuel injector.
- Connect a test lamp between the control circuit and the ignition voltage circuit of the harness connector.
- Verify the test lamp flashes while cranking the engine.
- If the test lamp does not flash
Refer to Fuel Injector Diagnosis .
- If the test lamp flashes
- If the test lamp does not flash
- Verify the conditions listed below do not exist:
- A collapsed air intake duct to the throttle body
- A restricted air filter or air intake system
- Coolant or gas fouled spark plugs
- A skewed manifold absolute pressure (MAP) sensor
- A skewed engine coolant temperature (ECT) sensor
- A restricted exhaust system. Refer to Restricted Exhaust .
- Contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- An engine mechanical condition, for example, worn timing chain and gears or low compression-Refer to Symptoms - Engine Mechanical
.
- If a condition exists
Repair as necessary.
- If a condition exists
- If no conditions exist
- All OK
NOTE:
It may be necessary to secure the EN 36012-A Ignition System Diagnostic Harness to the spark plug boots with electrical tape.
NOTE:
NOTE:
NOTE:
Perform the fuel injector test on at least 3 fuel injectors