U069F: Lost Communication With Exhaust Pressure Sensor C

What it means

Communication with exhaust pressure sensor C 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 Pressure Sensor C measures exhaust pressure for systems that use multiple pressure sensors. U069F sets when the receiving module stops getting messages from Sensor C, so exhaust or emissions functions that rely on that sensor may use fallback data or be limited.

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 and review freeze-frame data to determine when Exhaust Pressure Sensor C stopped communicating and whether related exhaust-system codes are present.
2. Check scan-tool data to confirm whether Sensor C is online and whether its pressure reading is available.
3. Inspect Sensor C's connector and harness for loose terminals, corrosion, chafing, or heat damage near the exhaust.
4. Check the sensor module's power and ground circuits against the manufacturer's specification.
5. Test the communication bus for opens or shorts using the manufacturer's procedure, then consider Sensor C itself if the network and supplies pass.

Common fixes

• Reconnect the Sensor C connector or repair damaged harness wiring.
• Repair an open or short in the communication bus serving Exhaust Pressure Sensor C.
• Restore the sensor module's power or ground, including replacing a failed fuse after checking the circuit.
• Replace Exhaust Pressure Sensor C if the bus, power, and ground are sound but it still does not communicate.

Can I keep driving?

If the vehicle drives normally, a short trip for diagnosis may be possible, but avoid heavy towing or hard acceleration because exhaust pressure and emissions control may be affected. Stop if power drops, the vehicle enters limp mode, or an exhaust-system warning appears.