Circuit/System Verification

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, 2018 Chevrolet Suburban, and 2018 Cadillac Escalade ESV. 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.
There is adequate fuel in the fuel tank.

Crank the engine for up to 15 seconds.
Verify that DTC P0116, P0117, P0118, P0119, P0121, P0122, P0123, P0201 - P0208, P0222, P0223, P0300 - P0308, P0335, P0336, P0351 - P0358, P0601 - P0604, P0606, P062B, P062F, P0630, P0633, P0685 - P0687, P0689, P0690, P1631, P1682, P16A0, P16A1, P16A2, P16F3, P2135 or P262B, is not set.
- If any of the DTCs are set
  Refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Go to next step: If none of the DTCs are set
Ignition ON.
Verify the security indicator illuminates momentarily.
- If the security indicator stays ON or is flashing
  Review the Diagnostic Trouble Code (DTC) List - Vehicle , for immobilizer system DTCs. Refer to Immobilizer Description and Operation for additional information.
- Go to next step: 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 .
- Go to next step: If greater than 0 RPM
Ignition OFF.
Install the J26792 HEI Spark Tester between the boot of a spark plug wire and ground.
NOTE: Perform the spark test on at least 1 cylinder of each cylinder bank.
Verify the spark tester sparks while cranking the engine.
- If the spark tester does not spark
  Refer to Electronic Ignition System Diagnosis .
- Go to next step: If the spark tester sparks
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 down to below 60°C (150°F) before attempting to verify fuel pressure.
- The scan tool Fuel Pump Enable may need to be commanded On a few times in order to obtain the highest possible fuel pressure.
Verify that the scan tool Fuel Pressure Sensor parameter is between 320 - 580 kPa (46 - 84 psi) with the fuel pump running.
- If not within the specified range
  Refer to Fuel System Diagnosis .
- Go to next step: If within the specified range
Verify that the fuel pressure, after the pump has turned off, decreases to 468 - 544 kPa (68 - 79 psi) and does not decrease greater than 34 kPa (5 psi) in 1 minute.
NOTE: The fuel pressure may vary slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant.
- If not within the specified range
  Refer to Fuel System Diagnosis .
- Go to next step: If within the specified range
Verify the conditions listed below do not exist:
- A stuck camshaft position actuator solenoid valve. It may be necessary to perform a dynamic test on the valve to verify correct operation. Refer to DTC P0010, P0011, P2088 or P2089 for instructions.
- Collapsed air intake duct to the throttle body
- Restricted air filter element
- Spark plugs for being fouled
- A skewed manifold absolute pressure (MAP) sensor - Refer to DTC P0106 .
- A skewed engine coolant temperature (ECT) sensor - Refer to DTC P0116 .
- Exhaust system restricted - Refer to Restricted Exhaust .
- Fuel contamination - Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- Engine mechanical condition such as worn timing chain and gears or low compression - Refer to Symptoms - Engine Mechanical or Engine Compression Test .
- If a condition exists
  Repair as necessary.
- Go to next step: If no condition exists
All OK.