Immobilizer to PCM Signal Error
Your car's security system (immobilizer) isn't talking properly to the engine computer. It's like a security guard who can't communicate with the main office, so the building won't unlock.
The PCM monitors the signal handshake between the immobilizer module and itself to verify authorized key presence. It checks for valid authentication codes and signal timing within expected parameters. Loss of this communication triggers the fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Immobilizer Signal Validity | Valid coded signal received within 500ms | No signal or invalid code received |
| Authentication Response Time | 200-400ms response window | Timeout or delayed response >500ms |
Code P1264 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, P1264 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.