U068C: Lost Communication With Turbocharger/Supercharger Inlet Pressure Sensor B

What it means

The vehicle bus reports loss of communication with smart turbocharger inlet pressure sensor B (compressor inlet). Pressure-ratio computation switches to a substitute value.

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

Turbocharger/supercharger inlet pressure sensor B measures pressure at the compressor inlet and reports it over the vehicle bus. This code sets when messages from sensor B are lost, forcing the pressure-ratio calculation 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. Save freeze-frame data and scan all modules for communication codes to see when inlet pressure sensor B dropped out and whether other bus devices were affected.
2. Inspect sensor B's compressor-inlet connector and harness for loose pins, corrosion, moisture, heat damage, or chafing.
3. Check the sensor module's power and ground according to the manufacturer's procedure to rule out a lost supply or ground.
4. Inspect sensor B's communication wiring and splices for opens or shorts, then test the bus circuit using the manufacturer's procedure.
5. If power, ground, and bus wiring are sound, use a capable scan tool to check whether sensor B responds before replacing its module.

Common fixes

• Reconnect or repair a loose, corroded, or damaged compressor-inlet sensor B connector.
• Repair an open, short, or damaged splice in the sensor B communication wiring.
• Restore the sensor module's power or ground connection.
• Replace turbocharger/supercharger inlet pressure sensor B if it remains offline after circuit checks pass.

Can I keep driving?

Keep driving only gently if the engine behaves normally; avoid towing, hard acceleration, and sustained boost while the pressure-ratio calculation lacks sensor B data. Stop if power drops sharply or a boost warning appears, since operation may become limited or unpredictable.