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 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 is 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 (i.e., 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) & a 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 occur red, but PCM has results. |
| 64 | Abnormal Exit Without Results - While performing test, error occurred and no results are available. |