P1218: CID Stuck High - Fuel Injector Circuit Malfunction
The P1218 code indicates that the Cylinder Identification (CID) sensor or circuit is stuck in a high voltage state. This sensor is used by the engine control module (ECM) to determine the firing order and synchronize fuel injection. A stuck high signal typically points to a short to voltage, a faulty sensor, or a wiring issue. This can cause misfires, poor fuel economy, and potential engine damage if not addressed.
1. Symptoms You Will Notice
- Check Engine Light on
- Engine misfire or rough idle
- Poor fuel economy
- Hard starting or stalling
2. Most Common Causes
- Faulty CID sensor
- Short to voltage in CID circuit
- Damaged wiring or connector
- ECM failure (rare)
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect CID sensor and wiring for damage or corrosion.
Step 3: Test CID sensor signal with a multimeter; should pulse low/high. If stuck high, check for short to voltage.
Step 4: Check continuity and resistance in CID circuit; repair or replace as needed.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with a stuck high CID signal can cause misfires and potential engine damage. Have it diagnosed promptly.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on whether the sensor, wiring, or ECM needs replacement.
5. Commonly Affected Makes
This is a manufacturer-specific code. The exact manufacturer is not confirmed in our current database.