Injector Circuit / IDM Codes Not Updated
The engine computer isn't receiving updated timing signals from the injector driver module (IDM), like a drummer not hearing the beat from the conductor. This prevents proper fuel injection synchronization with engine firing.
The ECU monitors communication updates from the IDM (Injector Driver Module) which controls fuel injector timing and pulse width. The IDM sends periodic status codes to confirm it's actively controlling injectors and responding to ECU commands. If these updates stop arriving within expected intervals, the ECU detects a communication failure.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| IDM Update Frequency | Updates received every 10-50 ms | No update detected for >100 ms |
| IDM Response Codes | Valid codes 0x01-0x0F received | Missing or invalid codes from IDM |
Code P1346 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, P1346 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.