U069C: Lost Communication With Exhaust Gas Temperature Sensor Bank 2 Sensor 3

What it means

Communication with exhaust gas temperature sensor bank 2 sensor 3 has been lost. The resulting effects depend on how the vehicle uses that sensor’s data.

At a glance

• Usually lights the warning light of the system that lost communication
• Affects emissions; the car can fail an emissions test

How it works

Exhaust gas temperature sensor bank 2 sensor 3 measures exhaust temperature at its installed point on the bank 2 exhaust system and communicates the reading over the vehicle bus. This code sets when communication with that particular sensor is lost, potentially leaving temperature-dependent engine or emissions strategies to use a substitute value.

Common causes

Most likely first.

1. Bus wiring open or shorted
2. Module without power or ground
3. Module failed

Symptoms

• Multiple warning lights may illuminate
• Affected modules may go into limp mode or shut down
• Specific functions inoperative depending on module
• Diagnostic tools may show communication faults

How to diagnose it

1. Record freeze-frame data and scan engine and emissions modules for other exhaust-temperature, aftertreatment, and communication codes.
2. Check live data for bank 2 sensor 3’s communication status and temperature reading, comparing it with other exhaust-temperature sensors where available.
3. Locate bank 2 sensor 3 using vehicle service information and inspect its connector and wiring for heat damage, chafing, or corrosion.
4. Check the sensor’s specified power and ground, since loss of supply can stop its network messages.
5. Test the bus wiring for an open or short using the wiring diagram and manufacturer procedures.
6. If wiring and supply are correct, determine whether bank 2 sensor 3’s module has failed.

Common fixes

• Reconnect or clean the bank 2 sensor 3 connector.
• Repair heat-damaged or chafed bus wiring to bank 2 sensor 3.
• Restore the sensor’s power or ground.
• Replace exhaust gas temperature sensor bank 2 sensor 3 if the circuit and supply are sound and the sensor module has failed.

Can I keep driving?

If the vehicle runs normally and has no exhaust-temperature or emissions warning, a short trip may be possible, but arrange diagnosis soon. Avoid heavy loads if warnings or reduced power occur, since missing bank 2 sensor 3 data can affect exhaust-temperature protection or emissions control.