U067E: Lost Communication With Exhaust Pressure Control Valve B Sensor/Switch

What it means

The vehicle bus reports loss of communication with smart exhaust pressure control valve B position sensor/switch. Closed-loop control loses its feedback.

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

The position sensor or switch for exhaust pressure control valve B reports valve position over the vehicle network so the control system can compare commanded and actual position. U067E sets when the receiving module stops getting messages from that sensor, removing closed-loop feedback for valve B.

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 and exhaust-control codes, and save freeze-frame data before clearing them.
2. Check live data for exhaust pressure control valve B's commanded and reported position to confirm whether feedback is missing.
3. Inspect valve B's sensor connector and network wiring for soot or heat damage, corrosion, loose pins, or chafing near the exhaust.
4. Check the sensor or module's power and ground against the manufacturer's specification.
5. Test the network circuit serving valve B's position sensor or switch for opens or shorts using the manufacturer's procedure.
6. If wiring and supplies pass, follow the manufacturer's diagnostic steps to determine whether the sensor, valve assembly, or its communication module has failed.

Common fixes

• Reconnect the valve B sensor connector and repair heat-damaged or chafed wiring.
• Restore a faulty power or ground connection to the sensor or its module.
• Repair an open or short in the network wiring to valve B's sensor or switch.
• Replace the confirmed failed position sensor, valve assembly, or communication module.

Can I keep driving?

If the engine runs normally, short gentle trips may be possible, but avoid heavy loads if power or exhaust-control warnings appear; poor valve feedback can affect emissions control and engine operation. Stop if the vehicle loses power severely or the exhaust system overheats.