Electronic Throttle Monitor PCM Override
The engine computer detected a problem with the electronic throttle system where it had to override the throttle's normal operation to prevent engine damage or unsafe behavior. Think of it like a safety override in an elevator that stops it if something goes wrong.
The ECM monitors throttle position sensor (TPS) signals and compares them to desired values from the accelerator pedal position sensor (APP). When the actual throttle position deviates beyond acceptable thresholds or fails to respond correctly, the PCM activates a safety override to prevent runaway throttle conditions.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| TPS vs APP mismatch | Difference less than 5-10% | Difference exceeds 10-15% for extended period |
| Throttle response time | Opens/closes within 100-200ms | Response delayed beyond 500ms or fails to respond |
Code P1585 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P1585 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.