U061F: Lost Communication With Exhaust Gas Temperature Sensor Bank 1 Sensor 1

What it means

The vehicle bus reports loss of communication with smart exhaust gas temperature sensor bank 1 sensor 1 (typically pre-cat). Catalyst protection and DPF regeneration logic switch to model-based estimates.

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 1 sensor 1 measures exhaust heat at the first monitored position on engine bank 1, typically before the catalytic converter. U061F sets when its expected network messages stop arriving, so catalyst protection or DPF regeneration may have to use estimated temperature instead of this sensor's reading.

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. Scan all modules for communication codes and save freeze-frame data to see whether the fault occurred during regeneration, high exhaust temperature, or a wider network outage.
2. Check live data for bank 1 sensor 1 and compare its status with other exhaust temperature sensors when the engine is cold and warming up.
3. Inspect the sensor's connector and nearby hot-zone wiring for melted insulation, chafing, corrosion, or loose pins.
4. Verify the sensor module's power and ground using the manufacturer's wiring information.
5. Test the network circuit serving bank 1 sensor 1 for opens and shorts according to the manufacturer's procedure.
6. If power, ground, and wiring pass, confirm the sensor module has stopped transmitting before replacing it.

Common fixes

• Repair heat-damaged wiring or connector terminals for bank 1 sensor 1.
• Restore the sensor module's power or ground.
• Repair an open or short in the network wiring.
• Replace the bank 1 sensor 1 module if its supply and network circuit are sound but it does not communicate.

Can I keep driving?

Avoid heavy loads and prolonged high-speed driving until the fault is diagnosed, since the engine may lack reliable temperature feedback for catalyst protection or regeneration. Seek prompt service if an emissions warning, reduced power, or a DPF warning appears.