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) 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.
| 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 |
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.