The numbers below refer to the step numbers on the diagnostic table.
Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
Step | Action | Yes | No |
---|---|---|---|
1 | Install a scan tool. Does the scan tool power up? | Go to Step 2 | Go to Scan Tool Does Not Power Up in Computer/Integrating Systems |
Does the scan tool communicate with the PCM? | Go to Step 3 | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Computer/Integrating Systems | |
3 | Select the PCM display DTCs function on the scan tool. Does the scan tool display any DTCs? | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
Does the scan tool display any DTCs which begin with a "U"? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Computer/Integrating Systems | Go to Step 5 | |
5 | Does the scan tool display DTC P1637? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle Control Systems | Go to Step 6 |
6 | Does the scan tool display any DTCs which begin with "P" other then P0801, P0803? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle Control Systems | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle Control Systems |