P1667 - CID Circuit Failure
The P1667 code indicates a failure in the Cylinder Identification (CID) circuit, which is part of the ignition system used to identify which cylinder is firing. This circuit typically involves a sensor or signal from the crankshaft or camshaft position sensor. A failure can cause misfires, rough running, or no-start conditions. The issue is often due to a faulty sensor, wiring problems, or a damaged PCM.
1. Symptoms You Will Notice
- Engine misfire or rough idle
- Check Engine Light illuminated
- Hard starting or no-start condition
2. Most Common Causes
- Faulty or stuck starter relay
- Damaged, corroded, or shorted wiring in the starter relay control circuit (between PCM and fuse/relay box)
- Internal PCM failure in the starter relay driver
- Defective PATS module or interrupted PATS-PCM communication
- Unprogrammed key or faulty key transponder
- Blown fuse in the starter relay power supply circuit
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for related codes.
Step 2: Inspect the wiring and connectors for the CID circuit for damage or corrosion.
Step 3: Test the crankshaft and camshaft position sensors with a multimeter or oscilloscope.
Step 4: If sensors and wiring are okay, test the PCM for proper signal output.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can cause engine misfires and potential damage to the catalytic converter.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for sensor replacement, but can be higher if the PCM needs replacement.
5. Commonly Affected Makes
This is a manufacturer-specific code. The exact manufacturer is not confirmed in our current database.