What it means
The control module detects a low condition in the cylinder 12 injector circuit. This indicates an electrical circuit fault and does not by itself establish an injector flow problem.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The injector circuit supplies the electrical command for cylinder 12's fuel injector. P0294 sets when the control module detects a circuit voltage that is too low; this indicates an electrical fault and does not by itself show that the injector is clogged.
Common causes
Most likely first.
- Wiring shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check-engine light
- Rough running or misfire
- Reduced engine power
- Hard starting
How to diagnose it
- Use a scan tool to review freeze-frame data and check for cylinder 12 misfire or injector-circuit codes recorded at the same time.
- Inspect the cylinder 12 injector connector and harness for chafing, corrosion, moisture, or terminals pushed back in the connector.
- With the circuit active, gently move the cylinder 12 harness while monitoring the circuit reading to check for an intermittent fault.
- Test the cylinder 12 injector control wire for a short to ground and check terminal contact using the manufacturer's procedure.
- If the harness checks out, test the injector and module driver circuit against the manufacturer's specification.
Common fixes
- Repair cylinder 12 injector wiring that is shorted to ground or chafed.
- Clean or replace corroded cylinder 12 connector terminals and damaged seals.
- Restore a pushed-back or loose connector terminal.
- Replace the cylinder 12 injector or repair the driver circuit only if testing identifies it as faulty.
Can I keep driving?
A cylinder 12 injector circuit fault can cause rough running, misfire, and reduced power. Avoid hard driving, and stop if the engine runs severely rough or the warning light flashes because continued misfiring can damage the catalyst.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.