NOx Sensor Heater Control Circuit/Open Bank 2
The NOx sensor heater control circuit on Bank 2 has detected an open circuit condition, meaning the heater element cannot be properly energized. This prevents the NOx sensor from reaching optimal operating temperature, causing it to fail emissions monitoring and trigger the code.
What You Might Notice
- Check Engine Light (CEL) illuminated
- Failed emissions test
- Intermittent CEL flashing
- Reduced engine performance
- Increased emissions output
Most Common Causes
- 1
Open or broken heater wiring
The electrical circuit connecting the NOx sensor heater has a break, corrosion, or poor connection preventing current flow to the heating element.
- 2
Failed NOx sensor heater element
The internal heater resistor within the NOx sensor on Bank 2 has failed or burned out, breaking the circuit path.
- 3
Faulty NOx sensor connector
The connector pins are corroded, loose, or damaged, preventing proper electrical contact between the harness and sensor.
- 4
ECM relay or control module failure
The engine control module relay or internal circuit controlling the NOx heater is not supplying power to the sensor heater circuit.
How to Diagnose It
- 1
Check Open or broken heater wiring — The electrical circuit connecting the NOx sensor heater has a break, corrosion, or poor connection preventing current flow to the heating element.
- 2
Check Failed NOx sensor heater element — The internal heater resistor within the NOx sensor on Bank 2 has failed or burned out, breaking the circuit path.
- 3
Check Faulty NOx sensor connector — The connector pins are corroded, loose, or damaged, preventing proper electrical contact between the harness and sensor.
- 4
Check ECM relay or control module failure — The engine control module relay or internal circuit controlling the NOx heater is not supplying power to the sensor heater circuit.
How to Fix It
- 1
Inspect and repair heater wiring
Locate the NOx sensor heater circuit on Bank 2, check for broken, corroded, or disconnected wires. Repair or replace damaged sections and ensure all connections are secure.
- 2
Replace NOx sensor
Remove the faulty NOx sensor on Bank 2 and install a new OEM or quality replacement sensor with functioning heater element.
- 3
Clean or replace sensor connector
Disconnect the NOx sensor connector, clean corrosion from pins using contact cleaner, or replace the connector if pins are damaged beyond cleaning.
- 4
Test and replace ECM relay
Using a multimeter, test the NOx heater control relay for proper voltage and operation. Replace the relay if it fails to energize the heater circuit.
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