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DTC codes / U06xx · Network communication / U068E

U068ELost Communication With EGR Temperature Sensor B

U068E is a network communication code indicating that a control module on the vehicle's Controller Area Network (CAN) bus has lost contact with the Exhaust Gas Recirculation (EGR) Temperature Sensor B. The module that monitors this sensor, often the Engine Control Module (ECM) or a dedicated EGR controller, has stopped receiving valid temperature data over the communication bus, which can affect EGR system operation and emissions control.

SystemNetwork
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaNetwork communication

Symptoms you may notice

  • Illumination of the Check Engine Light or Service Engine Soon light, often with no other noticeable symptoms.
  • Rough or unstable engine idle, particularly when the engine is cold or during EGR activation.
  • Reduced fuel economy as the ECM may default to a less efficient fueling strategy.
  • Failed emissions test due to an incomplete or failed EGR monitor.
  • Intermittent engine hesitation or stumble during light acceleration.
  • Other communication-related warning lights if the fault is part of a broader bus issue.

Common causes, most likely first

  1. Damaged, corroded, or disconnected wiring or connector at the EGR temperature sensor B or its harness.
  2. Failed EGR temperature sensor B itself, causing the module to stop transmitting data.
  3. Faulty CAN bus wiring (open, short, or high resistance) between the sensor module and the ECM.
  4. Poor ground connection for the EGR sensor circuit or the module that reports the sensor data.
  5. Failed control module (ECM or EGR controller) that cannot communicate on the bus.
  6. Software or calibration issue in the ECM causing intermittent loss of communication.
  7. Aftermarket accessories or improper electrical repairs introducing bus interference.

How to diagnose and fix it

  1. Perform a visual inspection of the EGR temperature sensor B connector and harness for corrosion, damage, or loose pins.
  2. Use an OBD-II scan tool to check for communication with the module that reports EGR temperature sensor B and verify live data availability.
  3. Measure resistance and voltage on the sensor signal circuit and compare to manufacturer specifications.
  4. Check CAN bus continuity and resistance (typically 60 ohms across the bus) to rule out wiring faults.
  5. Inspect and clean ground connections for the EGR sensor and the control module.
  6. If wiring and sensor test good, substitute a known-good sensor or module to isolate the faulty component.
  7. Repair or replace the faulty wiring, sensor, or module as needed, then clear codes and verify communication is restored.

When U068E is not the sensor's fault

  • A loose or corroded ground at the EGR sensor or module can mimic a failed sensor and set U068E without any sensor defect.
  • The code often appears after battery replacement or jump-starting if the module loses its communication configuration temporarily.
  • CAN bus faults from unrelated modules or aftermarket electronics can disrupt EGR temperature sensor B communication, so always check for other U-codes.
  • Some vehicles use a dedicated EGR controller that reports sensor B data; a failure in that controller can set U068E even when the sensor itself is fine.
  • Intermittent U068E codes are frequently caused by chafed wiring near hot exhaust components, which only lose contact when the engine bay reaches operating temperature.

Can I keep driving with U068E?

The vehicle is generally safe to drive with U068E because it is a communication code and does not cause immediate safety hazards, but prolonged driving may increase emissions and reduce fuel economy. Avoid heavy loads or long trips until the fault is diagnosed, and address the code promptly to prevent secondary EGR system damage.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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