Communication Error
If scan tool will not communicate with PCM (no response on scan tool) or will not respond to a particular request, a communication error exists. A communication error could be caused by the following:
- Operator error.
- Vehicle wiring.
- DLC terminals damaged.
- PCM malfunction.
- Low battery voltage.
The scan tool may display a 2-digit code indicating communication status. These codes are communication status codes, not DTCs. Some status codes indicate normal communication function. See COMMUNICATION CODES table. If scan tool displays a system okay code (Code 62) after performing QUICK TEST , proceed to TESTS W/O CODES article for symptom diagnosis. If scan tool indicates a communication error (e.g., Code 10), go to CIRCUIT TEST QA under CIRCUIT TESTS for diagnostic procedure.
COMMUNICATION CODES
| Code | Description |
|---|---|
| 00 | General Affirmative - PCM Received A Valid Request From Scan Tool |
| 10 | General Reject - PCM Will Not Respond |
| 11 | Mode Not Supported - PCM Not Capable Of Performing A Requested Test |
| 12 | Invalid Data Format - An Unrecognized Character Is Inserted Into A String Of Data |
| 21 | PCM Is Busy At Time Of Request - PCM Is Already Performing A Test At Time Another Test Is Being Requested |
| 22 | Entry Conditions Not Correct - Usually Operator Error (Engine Not Running, Etc.) |
| 23 | Results Not Done - Request Received, But PCM Is Not Ready To Respond |
| 50 | Upload Not Accepted - Request Cannot Be Accomplished Due To Fault Condition |
| 61 | Normal Exit With Results - PCM Completed A Valid Request (Test) & DTC Was Recorded |
| 62 | Normal Exit, No Results - PCM Completed A Valid Request & No DTC Recorded |
| 63 | Abnormal Exit With Results - While Performing Test, Error Occurred, But PCM Has Results |
| 64 | Abnormal Exit Without Results - While Performing Test, Error Occurred And No Results Are Available |