P1218 - CID (Cylinder Identification) Signal Stuck High
The P1218 code indicates that the Engine Control Module (ECM) has detected the Cylinder Identification (CID) signal from the camshaft position sensor is stuck in a high voltage state. This signal is used to synchronize fuel injection and ignition timing. A stuck high condition typically points to a short to voltage in the sensor circuit, a faulty sensor, or an ECM issue. This can cause misfires, rough running, and potential engine damage if not addressed.
01. Most Common Causes
- Camshaft position sensor shorted to battery voltage
- Wiring harness damage causing short to power
- Faulty ECM (rare)
02. Symptoms You Will Notice
- Check Engine Light on
- Engine misfire or rough idle
- Hard starting or no start
- Reduced engine performance
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and record freeze frame data.
Step 2: Visually inspect the camshaft position sensor wiring for damage or shorts.
Step 3: Test the sensor signal voltage with a multimeter; should pulse between 0-5V, not stuck high.
Step 4: Check for shorts to battery voltage in the sensor circuit.
Step 5: Replace the camshaft position sensor if circuit tests pass but signal is stuck high.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, driving with P1218 can cause engine misfires, stalling, and potential catalytic converter damage. It is best to have it diagnosed and repaired promptly.
How much does it cost to fix?▼
Typically $50-$150 for a camshaft position sensor replacement, including parts and labor. Wiring repairs may cost more if extensive damage is found.