Subject: | Revised Engine Cranks But Does Not Run Diagnostic Procedure |
Models: | 2001-2002 Chevrolet Camaro, Corvette |
2001-2002 Pontiac Firebird |
This bulletin is being issued to revise the Engine Cranks But Does Not Run diagnostic procedure in the Engine Controls sub-section of the Service Manual. Please replace the current information in the Service Manual with the following information.
The following information has been updated within SI. If you are using a paper version of this Service Manual, please make a reference to this bulletin on the affected page.
The diagnostic table identifies a condition that causes an engine to not start. The diagnostic table directs the service technician to the appropriate system diagnosis. The diagnostic table assumes the following conditions are met:
• | The battery is completely charged. Refer to Battery Inspection/Test in Engine Electrical. |
• | The engine cranking speed is within specification. Refer to Engine Cranks Slowly in Engine Electrical. |
• | There is adequate fuel in the fuel tank. |
Inspect for the following conditions:
• | The mass air flow (MAF) is compared to a calculated mass air flow based upon the manifold absolute pressure (MAP), the throttle position (TP), and the engine RPM. A skewed or unresponsive MAP sensor at key on will cause the predicted air flow value to be inaccurate. Compare the MAP and TP readings to that of a known good vehicle. |
• | A faulty engine coolant temperature (ECT) sensor. Use a scan tool in order to compare the ECT with the intake air temperature (IAT) on a completely cooled engine. The ECT should be within 3°C (5°F) of the IAT. |
• | For an intermittent condition, refer to Intermittent Conditions. |
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | ||||||||||||
2 | Crank the engine for the specified amount of time. Does the scan tool display any DTCs that failed this ignition? | 15 seconds | Go to Diagnostic Trouble Code (DTC) List | Go to Step 3 | ||||||||||||
3 | Inspect the body control module (BCM) for DTCs related to the vehicle theft deterrent (VTD) system. Does the scan tool display any BCM vehicle theft deterrent DTCs? | -- | Go to Diagnostic System Check - Theft Deterrent in Theft Deterrent | Go to Step 4 | ||||||||||||
4 | Monitor the engine speed while cranking the engine. Is engine RPM indicated on the scan tool? | -- | Go to Step 5 | Go to DTC P0335 | ||||||||||||
Does the test lamp illuminate on both sides of the fuses? | -- | Go to Step 6 | Go to Ignition Relay Diagnosis | |||||||||||||
6 |
Does the HEI Spark Tester spark? | -- | Go to Step 7 | Go to Electronic Ignition (EI) System Diagnosis | ||||||||||||
7 | Use the scan tool in order to monitor the engine coolant temperature (ECT). Is the ECT on the scan tool close to the actual engine temperature? | -- | Go to Step 8 | Go to DTC P0118 | ||||||||||||
8 | Use the scan tool in order to enable the fuel pump. Does the fuel pump operate? | -- | Go to Step 9 | Go to Fuel Pump Electrical Circuit Diagnosis | ||||||||||||
9 |
Important: The fuel pump operates for about 2 seconds when the ignition is turned ON. The fuel pressure must be observed when the fuel pump is operating. Is the fuel pressure within the specified range? | 379-427 kPa (55-62 psi) | Go to Step 10 | Go to Fuel System Diagnosis | ||||||||||||
10 | Perform the following additional inspections:
Did you find and correct the condition? | -- | Go to Step 11 | Go to Hard Start | ||||||||||||
11 |
Does the engine start and continue to run? | -- | Go to Step 12 | Go to Step 2 | ||||||||||||
12 |
Are any DTCs displayed? | -- | Go to Diagnostic Trouble Code (DTC) List | Go to Step 13 | ||||||||||||
13 | Use the scan tool in order to select the Capture Info option and the Review Info option. Are any DTCs displayed that you have not diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List | System OK |
The Engine Cranks but Does Not Run diagnostic table is an organized approach to identifying a condition that causes an engine to not start. The diagnostic table directs the service technician to the appropriate system diagnosis. The diagnostic table assumes the following conditions are met:
• | The battery is completely charged. Refer to Battery Inspection/Test in Engine Electrical. |
• | The engine cranking speed is within specification. Refer to Engine Cranks Slowly in Engine Electrical. |
• | There is adequate fuel in the fuel tank. |
Check for the following conditions:
• | The mass air flow (MAF) is compared to a calculated mass air flow based upon the manifold absolute pressure (MAP), the throttle position (TP), and the engine RPM. A skewed or unresponsive MAP sensor at key on will cause the predicted air flow value to be inaccurate. Compare the MAP and TP readings to that of a known good vehicle. |
• | Check for a faulty engine coolant temperature (ECT) sensor. Use a scan tool in order to compare the ECT with the intake air temperature (IAT) on a completely cooled engine. The ECT should be within 3°C (5°F) of the IAT. |
• | For an intermittent condition, refer to Intermittent Conditions. |
The numbers below refer to the step numbers on the diagnostic table.
This step tests the ignition relay for proper operation. The ignition relay supplies voltage to the injectors and the ignition coils. When the ignition relay is not operating properly, a no start condition occurs. If the test lamp does not illuminate, this indicates the ignition relay is not supplying a voltage to the fuses.
Step | Action | Values | Yes | No | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | ||||||||||||
2 |
Does the scan tool display DTC P0230, DTC P0335, DTC P0336, DTC P0601, DTC P0602, DTC P0604, DTC P0606, DTC P1626 or DTC P1631? | -- | Go to Diagnostic Trouble Code (DTC) List | Go to Step 3 | ||||||||||||
3 | Check the body control module (BCM) for DTCs related to the vehicle theft deterrent (VTD) system. Does the scan tool display any BCM VTD DTCs? | -- | Go to Diagnostic System Check - Theft Deterrent in Theft Deterrent | Go to Step 4 | ||||||||||||
4 | Monitor the engine speed while cranking the engine. Is engine RPM indicated on the scan tool? | -- | Go to Step 5 | Go to DTC P0335 | ||||||||||||
5 |
Does the test lamp illuminate on both sides of the fuses? | -- | Go to Step 6 | Go to Ignition Relay Diagnosis | ||||||||||||
6 |
Does the spark tester spark? | -- | Go to Step 7 | Go to Electronic Ignition (EI) System Diagnosis | ||||||||||||
7 | Monitor the engine coolant temperature (ECT) using the scan tool. Is the ECT on the scan tool close to the actual engine temperature? | -- | Go to Step 8 | Go to DTC P0118 | ||||||||||||
8 | Enable the fuel pump using the scan tool. Does the fuel pump operate? | -- | Go to Step 9 | Go to Fuel Pump Electrical Circuit Diagnosis | ||||||||||||
9 |
Important: The fuel pump operates for about 2 seconds when the ignition is turned ON. The fuel pressure must be observed when the fuel pump is operating. Is the fuel pressure within the specified range? | 379-427 kPa (55-62 psi) | Go to Step 10 | Go to Fuel System Diagnosis | ||||||||||||
10 | Perform the following additional inspections:
Did you find and correct the condition? | -- | Go to Step 11 | Go to Hard Start | ||||||||||||
11 |
Does the engine start and continue to run? | -- | Go to Step 12 | Go to Step 2 | ||||||||||||
12 |
Are any DTCs displayed? | -- | Go to Diagnostic Trouble Code (DTC) List | Go to Step 13 | ||||||||||||
13 | Select the Capture Info option and the Review Info option using the scan tool. Are any DTCs displayed that you have not diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List | System OK |