For 1990-2009 cars

### Description

This diagnostic test applies to internal microprocessor integrity conditions within the control module. This diagnostic test also addresses if the control module is not programmed. The following diagnostic trouble codes (DTCs) are diagnosed in this DTC table:

Important: The DTCs listed below, are not applicable to all vehicles.

• | DTC P0601

• | DTC P0602

• | DTC P1683

### Diagnostic Aids

For complete details on programming the PCM, refer to Service Programming System (SPS) Description .

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. A DTC P0602 indicates the PCM is not programmed.

2. Attempt to program the PCM. If the PCM fails to program a second time, replace the PCM.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls
2 | Is DTC P0602 set? | Go to Step 3 | Go to Step 5
3 | Program the PCM. Refer to Powertrain Control Module Programming . Does DTC P0602 reset? | Go to Step 4 | Go to Step 6
4 |

1. Verify that all tool connections are secure.
2. Verify the programming equipment is operating correctly.
3. Verify the correct software package and the correct calibration package is used.
4. Attempt to program the PCM. Refer to Powertrain Control Module Programming .

Does DTC P0602 reset?

Go to Step 5

Go to Step 6

5 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | Go to Step 6 | --
6 |

1. Turn ON the ignition, with the engine OFF.
2. Use a scan tool in order to clear DTCs.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.

Does the scan tool display any DTCs?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 7

7 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | Go to Diagnostic Trouble Code (DTC) List | System OK