Cylinder 12 Injector Circuit Low
The P0294 code indicates that the powertrain control module (PCM) has detected a low voltage or resistance condition in the electrical circuit for the fuel injector on cylinder 12. This typically means the injector's electrical circuit is shorted to ground, has an open circuit, or the injector itself is faulty. The PCM monitors the injector driver circuit and sets this code when the current flow is lower than expected, often due to wiring issues, a failed injector, or a problem with the PCM driver.
1. Most Common Causes
- Faulty fuel injector on cylinder 12 or altered internal resistance
- Short to ground in the injector circuit wiring
- Loose connection or corrosion at the injector connector
- Excessive resistance in the wiring harness due to damage or wear
- Failed injector driver inside the ECM/PCM
- Defective injector power fuse or relay (if applicable to vehicle design)
2. Symptoms You Will Notice
- Engine misfire on cylinder 12
- Rough idle or hesitation
- Check Engine Light illuminated
- Reduced fuel economy and performance
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to verify the code and check for additional codes.
Step 2: Inspect the wiring and connector at cylinder 12 injector for damage, corrosion, or loose connections.
Step 3: Measure resistance of the injector; compare to specifications (typically 12-16 ohms).
Step 4: Check for voltage at the injector connector with key on; should be battery voltage on one pin.
Step 5: Perform a injector balance test or use a noid light to confirm injector operation.
Step 6: If wiring and injector are good, test the PCM injector driver circuit.
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 misfire, reduced performance, and potential damage to the catalytic converter. Have it diagnosed and repaired promptly.
How much does it cost to fix?▼
The cost to fix P0294 typically ranges from $150 to $400, depending on whether the injector needs replacement or if it's a wiring repair. Injector replacement parts cost $50-$150, plus labor.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.