U0652: Lost Communication With EGR Sensor B

What it means

A control module has stopped receiving expected network messages from EGR sensor B. The sensor's function and the effect on EGR operation depend on the vehicle's system design.

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

EGR sensor B supplies a measurement used by the exhaust-gas recirculation system, with its precise function depending on vehicle design. This code sets when a module stops receiving expected messages from sensor B, leaving that sensor's EGR feedback unavailable.

Common causes

Most likely first.

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

Symptoms

• Warning light or message related to the affected system
• EGR operation may be affected

How to diagnose it

1. Record freeze-frame data and scan all modules for EGR and communication codes to identify when sensor B messages disappeared.
2. Check live data specifically for the sensor B reading and whether it updates when EGR operation is commanded.
3. Inspect EGR sensor B's connector and network wiring for loose pins, corrosion, heat damage, or chafing.
4. Check power and ground at sensor B or its associated module using the manufacturer's wiring information.
5. Test the network circuit serving sensor B for opens or shorts, then assess sensor B or its module if the circuit and feeds pass.

Common fixes

• Reconnect or clean the EGR sensor B connector.
• Repair damaged network wiring or connector terminals serving sensor B.
• Restore the sensor module's power or ground.
• Replace EGR sensor B or its module if wiring and electrical feeds pass but messages do not return.

Can I keep driving?

If the engine runs normally, a short trip may be possible, but avoid heavy loads if power or smoothness worsens. Loss of EGR feedback can increase emissions and affect engine performance.