U010B: Lost Communication With Exhaust Gas Recirculation Control Module B

What it means

A control module has lost communication with exhaust gas recirculation control module B. EGR operation may be affected on vehicles that use this module.

At a glance

• Affects emissions; the car can fail an emissions test

How it works

Exhaust gas recirculation control module B manages or reports a second EGR control unit on vehicles equipped with one. The EGR system recirculates some exhaust gas to help control combustion emissions, and module B shares status over the vehicle network. U010B sets when a reporting module stops receiving expected messages from EGR control module B.

Common causes

Most likely first.

1. Loss of module power or ground
2. Open, shorted, or damaged communication wiring or connector
3. Module or gateway fault

Symptoms

• Warning lights or messages
• Communication faults in other modules
• Engine performance or emissions symptoms may occur

How to diagnose it

1. Scan all modules for U010B and related EGR or network codes, and save freeze-frame details to identify when module B communication was lost.
2. Check for EGR warnings or engine and emissions symptoms, and confirm whether scan-tool data from module B is missing.
3. Locate module B using vehicle service information, then inspect its connector and harness for corrosion, heat damage, loose pins, or chafing.
4. Check module B's power and ground circuits against the manufacturer's specification.
5. Test module B's communication wiring for opens, shorts, or poor connections using the vehicle wiring diagram.
6. If its supplies and network path are sound, use vehicle-specific diagnostics to assess module B and the EGR system before replacing components.

Common fixes

• Secure or clean a loose or corroded EGR control module B connector.
• Repair damaged wiring or a poor ground at module B.
• Restore module B's power supply and correct the cause of a failed fuse.
• Repair a gateway or network fault if testing identifies it.
• Replace or program EGR control module B only after its circuits and related EGR components have been checked.

Can I keep driving?

If the engine runs normally, cautious short-distance driving is generally possible, but emissions performance may be affected. Stop if the engine runs very poorly or loses power, and avoid driving in a way that worsens those symptoms.