The engine control module has detected irregular engine speed when the throttle is closed
SYMPTOM-ROUGH-IDLE — The engine control module has detected irregular engine speed when the throttle is closed. In plain English, the computer sees the engine shaking or vibrating at idle and logs SYMPTOM‑ROUGH‑IDLE to wa. It is a medium-severity fault: you can usually keep driving for short distances. The most common cause is visual inspection & loose connections.
"Caution: ignore it long enough and it gets expensive opinions about your wallet."
SYMPTOM-ROUGH-IDLE is a powertrain diagnostic trouble code. It identifies a fault related to The engine control module has detected irregular engine speed when the throttle is closed. In plain English, the computer sees the engine shaking or vibrating at idle and logs SYMPTOM‑ROUGH‑IDLE to wa. The powertrain control module monitors this circuit or component continuously and sets SYMPTOM-ROUGH-IDLE when the signal or value is outside the expected range, implausible or missing. This can affect engine performance, fuel economy or emissions and usually turns on the check-engine light. The base function may still work, but performance can be affected, so the fault should be diagnosed. Diagnosis generally means inspecting the related wiring, connectors and power/ground references, then verifying the component against specification with a scan tool.
- Check-engine light illuminated
- Possible rough running, reduced power or higher fuel consumption
- Fault code stored in the control module
| # | Cause |
|---|---|
| 01 | Visual Inspection & Loose Connections |
| 02 | Check for Stored Trouble Codes |
| 03 | Inspect the Ignition System |
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YES, WITH CAUTION — get it diagnosed as soon as possible.