Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Communication Error
If scan tool will not communicate with PCM (no response on scan tool), 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 not DTCs. Some status codes indicate normal communication function. See COMMUNICATION CODES table. If scan tool indicates a communication error (e.g., Code 10), go to CIRCUIT TEST QA for diagnostic procedure.
| Code Number | Code Description | Code Explanation |
|---|---|---|
| 00 | General Affirmative | PCM Received A Valid Request From Scan Tool |
| 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 |
| 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 |
| 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 |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.