01 Ford’s Iconic Blue Oval Logo Gets a Refresh • 02 Turbochargers and Superchargers: Boosting Performance with … • 03 Exploring the Toyota 1NZ Engine: Features and Performance A… • 04 Why are not all tires on a car the same width? • 05 Troubleshooting No Spark Issues in Modern Cars: A Comprehen… • 06 The Mechanism of Timing Chains: Understanding their Functio… • 07 The Best Oil for Older Diesel Engines: Buyer's Guide • 08 5 Reasons Why Your Car Wont Start When The Engine is Hot & … • 09 This Is How A Wing Actually Generates Lift And Why It’s Not… • 10 C0035 - Left Front Wheel Speed Circuit Malfunction •

DTC codes / U06xx · Network communication / U068D

U068DLost Communication With EGR Temperature Sensor A

U068D is a network communication fault 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 A. The computer did not detect an implausible temperature reading; instead, it noted that the periodic digital messages from that sensor's smart module stopped arriving within the expected time window.

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

Symptoms you may notice

  • Illumination of the malfunction indicator lamp (check engine light), often with no other noticeable symptoms.
  • Intermittent or permanent loss of communication with the EGR temperature sensor, which may cause the powertrain control module to disable EGR monitoring and set related emissions codes.
  • Rough idle or slight hesitation during light acceleration if the EGR system is commanded off as a default strategy.
  • A stored pending or history code for the same sensor that reappears after clearing, especially in damp or hot conditions.
  • No drivability change at all in many cases, because the fault is purely a data-bus communication loss rather than a sensor signal failure.

Common causes, most likely first

  1. Corroded, loose, or water-intruded electrical connector at the EGR temperature sensor A or at the module that hosts it.
  2. Damaged or chafed wiring in the CAN bus segment between the sensor module and the network gateway or powertrain control module.
  3. Failed EGR temperature sensor A module, where the internal communication driver stops responding even though the sensing element may still work.
  4. Low or unstable battery voltage, or a weak ground connection shared by the sensor module, causing it to drop off the bus intermittently.
  5. A faulty network gateway or a separate module on the same CAN segment that is shorting the bus and disrupting all messages, including those from the EGR temperature sensor.
  6. Software or calibration issue in the powertrain control module that incorrectly times out the sensor's messages under certain operating conditions.

How to diagnose and fix it

  1. Verify battery state of charge and perform a voltage drop test on the sensor module's power and ground circuits before condemning any part.
  2. Inspect the EGR temperature sensor A connector and the harness for corrosion, pushed pins, or water intrusion, then clean and reseat the connector.
  3. Use a scan tool to read live CAN bus data and confirm whether other modules on the same segment are also missing, which points to a shared bus fault rather than the sensor alone.
  4. Perform a resistance and continuity check on the CAN high and CAN low wires from the sensor module to the gateway, looking for opens, shorts to ground, or shorts to voltage.
  5. Substitute a known-good EGR temperature sensor A module only after wiring and power checks pass, then clear codes and verify communication returns.
  6. Check for technical service bulletins or calibration updates for the powertrain control module that address communication timeouts with emissions sensors.
  7. After repair, drive the vehicle through a complete EGR monitor cycle and confirm the code does not return as pending or stored.

Why this code is often a wiring fault

  • U068D is frequently set by a poor ground at the sensor module rather than a failed sensor, because a marginal ground causes the module's CAN transceiver to drop offline intermittently.
  • A single shorted module elsewhere on the same CAN segment can prevent the EGR temperature sensor's messages from getting through, so technicians who replace the sensor first often see the code return.
  • The code can be stored as history after a one-time low-voltage event such as a jump start, and it may never return once the battery is healthy and the code is cleared.
  • Some vehicles use the EGR temperature sensor A as part of a smart sensor cluster, meaning the communication loss may actually originate at a shared connector that also feeds other emissions sensors.
  • Clearing U068D without repairing the underlying bus fault can cause the powertrain control module to run a default EGR strategy that increases NOx emissions and may trigger additional codes later.

Can I keep driving with U068D?

The vehicle is generally safe to drive because the fault affects emissions monitoring rather than engine control, but avoid long trips or heavy load until the communication loss is repaired. If the check engine light flashes or the engine runs rough, stop driving and have the bus fault diagnosed promptly.

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.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage