What it means
The cylinder 3 fuel heater control circuit is reporting a high condition. The code does not establish that this is a sensor heater or affects lambda control.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The engine control module monitors the electrical state of the fuel heater control circuit assigned to cylinder 3. This code sets when that circuit reads higher than expected, which can happen if the control line is shorted to a supply or a connection disrupts the expected signal.
Common causes
Most likely first.
- Control line shorted to supply
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light
- Fuel or powertrain warning light, if equipped
- Hard starting or rough running in cold weather
- Reduced engine performance in cold conditions
How to diagnose it
- Save freeze-frame data and review live data for the cylinder 3 heater command and circuit status, especially if the fault appeared during a cold start.
- Inspect the cylinder 3 heater harness for pinched insulation or contact with a battery-positive or other supply wire.
- Check the cylinder 3 heater connector for corrosion, backed-out pins, or poor terminal contact that could raise resistance.
- Using the manufacturer's wiring diagram and test procedure, measure the control line against ground and supply to determine whether it is being pulled high.
- If the wiring and connector are sound, test the heater and control module as directed by the manufacturer to isolate an internal fault.
Common fixes
- Clean and secure corroded or loose cylinder 3 heater connector terminals.
- Repair insulation where the cylinder 3 control wire is contacting a supply wire.
- Repair or replace a damaged cylinder 3 heater harness section.
- Replace the faulty heater or control module if testing confirms an internal fault.
Can I keep driving?
The vehicle may remain driveable if it runs normally, but the cylinder 3 heater may not work properly, making cold starting or cold-weather performance worse. Avoid extended use in very cold conditions until the circuit is checked.
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.