U010B

Universal

Lost Communication With Exhaust Gas Recirculation Control Module B

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
Medium Severity

The vehicle’s network is not receiving expected messages from Exhaust Gas Recirculation (EGR) Control Module B. EGR systems recirculate some exhaust gas to help control emissions, but this communication code does not prove that the EGR module or a particular EGR part has failed. Depending on the vehicle and whether EGR operation is affected, there may be no noticeable change, an emissions warning, or altered engine performance.

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⚠️ Before You Begin (Safety First)

This code alone does not usually indicate an immediate driving hazard. If the engine stalls, runs very poorly, or the vehicle cannot be controlled or driven safely, stop in a safe place and arrange assistance. Avoid disturbing wiring near hot or moving engine parts.

Common Symptoms

  • The check-engine or another warning light may appear because the vehicle has detected a communication fault.
  • There may be no noticeable symptoms if the fault is intermittent or the vehicle continues operating normally.
  • If EGR control is affected, engine performance or emissions may change; the exact effect depends on the vehicle’s system.
  • Other communication-related warning lights or codes may occur if the network fault affects additional modules.

Common Causes

  • A loose, damaged, corroded, or contaminated connector at the EGR control module or along its wiring.
  • A wiring fault that interrupts communication between the EGR control module and the rest of the vehicle network.
  • A power or ground supply problem that prevents the module from operating or communicating.
  • A broader vehicle network fault or a problem affecting another connected module.
  • An internal EGR control module fault, considered after its power, ground, connections, and network wiring are checked.

Diagnostic Steps

  1. Note when the warning appeared and whether there are changes in engine operation; this can help identify an intermittent or performance-related concern.
  2. Check the vehicle battery and charging system for obvious signs of a weak or disconnected supply, since voltage problems can affect module communication.
  3. With the vehicle safely parked and the engine off, visually inspect accessible EGR-module connectors and wiring for looseness, visible damage, corrosion, or contact with hot or moving parts. Do not pull on wires or disconnect components unless the vehicle-specific procedure permits it.
  4. Use a compatible scan tool, if available, to record codes from all modules before clearing anything. Related codes can help distinguish a local EGR-module connection problem from a wider network issue.
  5. If the code returns, or the module cannot be reached by the scan tool, arrange diagnosis using service information for the exact model, year, and engine.

When to Call a Professional

Scan all vehicle modules and compare communication-related codes before replacing parts. A technician can use vehicle-specific service information to check the EGR module’s power and ground, inspect its connectors and network wiring, and test network communication. A module fault should be considered only after its circuits and connections have been assessed.

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Commonly Asked Questions

Does U010B prove that the EGR control module needs replacement?

No. It indicates lost communication with EGR Control Module B, not a confirmed module failure. Wiring, connectors, power, ground, or a wider network issue can produce the same communication condition.

Does this code mean the EGR valve is mechanically stuck?

Not by itself. The code describes communication with the EGR control module; it does not identify a stuck valve or another specific mechanical fault.

Can I drive with U010B?

If the vehicle runs and drives normally, the code alone does not necessarily require stopping immediately. Do not continue driving if it stalls, runs very poorly, or becomes unsafe to control.

Why should other modules be scanned too?

Other communication codes may show whether the issue is limited to the EGR module or involves shared network wiring, power, or another module.

Browse Available Code Guides

Previous and next available guides in database record order, across makes. Adjacent entries may share a code number and do not necessarily describe related faults.