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DTC codes / U06xx · Network communication / U068F

U068FLost Communication With EGR Temperature Sensor C

U068F is a network communication code indicating that one or more control modules on the vehicle's Controller Area Network (CAN) bus have stopped receiving valid messages from the Exhaust Gas Recirculation (EGR) Temperature Sensor C. The computer did not detect an electrical fault inside the sensor itself; it detected the absence of expected data from that sensor's reporting module over the communication network.

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.
  • A stored U068F code accompanied by other communication or sensor codes in multiple modules.
  • Intermittent or complete loss of EGR monitoring, which may prevent the vehicle from completing an emissions readiness monitor.
  • Rough running or reduced fuel economy if the EGR system is disabled as a result of the missing temperature data.
  • Possible limp-home mode or reduced power if the affected module is critical to engine management.
  • No drivability complaints at all in many cases, especially when the fault is a brief network glitch.

Common causes, most likely first

  1. A faulty EGR temperature sensor C that has internally failed and stopped transmitting data on the network.
  2. Damaged, corroded, or loose wiring and connectors between the EGR temperature sensor C and its control module.
  3. A failed or intermittently failing control module that is responsible for reporting the EGR temperature sensor C data.
  4. CAN bus communication faults such as a shorted or open data line, often caused by chafed harnesses or water intrusion.
  5. Low battery voltage or a weak charging system that causes modules to drop offline intermittently.
  6. Aftermarket accessories or poor previous repairs that introduce electrical noise or incorrect resistance on the CAN bus.
  7. Software or calibration issues in a module that prevent it from broadcasting the EGR temperature sensor C signal.

How to diagnose and fix it

  1. Perform a full scan of all modules to record every stored and pending code, then clear codes and test-drive to see if U068F returns alone or with companion codes.
  2. Inspect the EGR temperature sensor C connector and harness for corrosion, loose pins, chafing, or water intrusion, and repair as needed.
  3. Measure battery voltage and charging system output to rule out low-voltage communication dropouts before condemning any module.
  4. Check the CAN bus resistance and voltage levels at the diagnostic connector to confirm the network is healthy and identify any shorted or open segments.
  5. If the sensor is accessible, test its resistance or signal output against the manufacturer's specification and replace it only if it fails the test.
  6. Verify that the module responsible for reporting EGR temperature sensor C is powered, grounded, and communicating, and reflash or replace it only after all wiring and power checks pass.
  7. After repairs, clear codes, complete a drive cycle, and confirm that the EGR monitor runs and that U068F does not reset.

Network Codes Are Rarely Just the Sensor

  • U068F is a communication code, not a direct sensor performance code, so replacing the EGR temperature sensor C without checking the network often fails to fix the problem.
  • A single failed module or a chafed CAN wire can set U068F alongside many unrelated communication codes, so the pattern of codes matters more than the code itself.
  • Low battery voltage from a weak battery or a failing alternator is a common hidden cause of intermittent U-codes that disappear after a good charge.
  • Aftermarket alarms, remote starters, or poorly installed accessories tapped into the CAN bus frequently introduce the electrical noise that triggers this code.
  • The EGR temperature sensor C may be part of a combined sensor assembly, so a failed sensor can also set codes for other EGR parameters that share the same housing.

Can I keep driving with U068F?

The vehicle is generally safe to drive short distances because U068F usually affects emissions monitoring rather than immediate engine operation, but avoid long trips or heavy load until the fault is diagnosed. If the engine runs rough, enters limp mode, or multiple warning lights appear, stop driving and have the network and sensor circuit inspected promptly.

Tools that help

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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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