What it means
The heater control circuit for the NOx sensor on bank 1 sensor 3 is open. Without the heater the sensor cannot reach operating temperature; readings stay invalid.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The heater control circuit warms the Bank 1 Sensor 3 NOx sensor so it can reach its operating temperature and provide usable readings. This code sets when the heater control path is open, so the module cannot drive or verify the heater as expected and the NOx readings may remain invalid.
Common causes
Most likely first.
- Open in heater control wiring
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
Symptoms
- Check engine light
- Possible NOx or aftertreatment warning
- Increased NOx emissions or failed emissions test
How to diagnose it
- Use a scan tool to review freeze-frame data, heater status, and any related NOx sensor codes to see when the open-circuit fault is detected.
- Inspect the Bank 1 Sensor 3 heater connector for a pushed-back pin, loose fit, corrosion, or heat damage.
- Trace the heater control wiring for breaks, pulled wires, or damage near the exhaust and sensor.
- Following the wiring diagram, check heater circuit continuity and the relevant power and control paths according to the manufacturer's procedure.
- If wiring and connector continuity are intact, test the sensor heater and control module for an internal open.
Common fixes
- Reconnect or repair a pushed-back or loose heater connector pin.
- Repair an open or broken heater control wire.
- Replace a damaged connector or terminal causing the open circuit.
- Replace the Bank 1 Sensor 3 NOx sensor or heater control module if testing confirms an internal open.
Can I keep driving?
If the vehicle runs normally, limit driving and have the heater fault checked soon. The sensor may not provide valid readings until warm, which can impair aftertreatment monitoring and increase NOx emissions.
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.