What it means
The cylinder 3 fuel heater control circuit is reporting a low 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 fuel heater control circuit assigned to cylinder 3. This code sets when the circuit reads lower than expected, often because the control line is shorted to ground or its wiring is damaged.
Common causes
Most likely first.
- Control line shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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 check live data for the cylinder 3 heater command and circuit status to see when the low reading occurred.
- Inspect the cylinder 3 heater harness for chafing, crushed insulation, or contact with engine ground.
- Check the cylinder 3 heater connector for corrosion, loose terminals, or pins pushed back into the connector body.
- With the manufacturer's wiring diagram, test the control line for an unintended short to ground and check continuity through the circuit.
- If the harness and connector pass, test the heater and control module using the manufacturer's procedure to identify an internal cause.
Common fixes
- Repair chafed cylinder 3 heater wiring and secure it away from ground points.
- Clean and reseat the cylinder 3 heater connector or repair its damaged terminals.
- Repair a shorted section of the cylinder 3 heater control wire.
- Replace the heater or control module only if testing confirms it is faulty.
Can I keep driving?
If the engine runs normally, short trips may be possible, but cold starting and performance can worsen when the heater is needed. Avoid depending on the vehicle for cold-weather starts until the fault is resolved.
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.