Test Description
Numbers below refer to the step number on the Diagnostic Chart:
- The Malfunction Indicator Lamp (MIL) should be ON steady with the ignition ON and the engine OFF. If not, go to "DIAGNOSTIC AIDS :"
- Checks the Class 2 data circuit and ensures that the ECM is able to transmit serial data.
- This test ensures that the ECM is capable of controlling the MIL and the MIL driver circuit is not shorted to ground.
- If the engine will not start, refer to "ENGINE CRANKS BUT WILL NOT RUN :".
- (7) A scan tool parameter which is not within the typical range may help to isolate the area which is causing the problem.
- (10) This vehicle is equipped with a ECM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). The replacement ECM must be programmed.
DIAGNOSTIC PROCEDURE
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| 1 |
Is the MIL illuminate? |
- | Go to Step 2 | Go to "NO MALFUNCTION INDICATOR LAMP :" |
| 2 |
Does the scan tool display the ECM engine data? |
- | Go to Step 3 | Go to Step 8 |
| 3 |
Does the MIL turn OFF? |
- | Go to Step 4 | Go to "MALFUNCTION INDICATOR LAMP ON STEADY :" |
| 4 | Attempt to start the engine. Does the engine start and continue to run? |
- | Go to Step 5 | Go to "ENGINE CRANKS BUT WILL NOT RUN : |
| 5 | Select DISPLAY DTC with the scan tool. Are any Diagnostic Trouble Codes (DTCs) stored? |
- | Go to Step 6 | Go to Step 7 |
| 6 | Check the display for DTCs P0107, P0108, P0113, P0118, P0122, P0123, P0712, P1392. Are two or more of the following DTCs stored? |
- | Go to "MULTIPLE ECM INFORMATION SENSOR DTCS SET :" | Go to APPLICABLE DTC TABLE |
| 7 | Compare the ECM data values displayed on the scan tool to the typical engine scan data values. Are the displayed values normal or close to the typical values? |
- | Go to Step 8 | Go to indicated component system check |
| 8 |
Is a problem found? |
- | Go to Step 9 | Go to Step 10 |
| 9 | Repair the open, short to ground, or short to voltage in the serial data circuit or the DLC ignition feed circuit. Is the repair complete? |
- | System OK | - |
| 10 |
Does the scan tool display ECM engine data? |
- | Go to Step 2 | Go to Step 11 |
| 11 | Replace the ECM. Is the replacement complete? |
- | System OK | - |