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DTC codes / U06xx · Network communication / U069D

U069DLost Communication With Exhaust Gas Temperature Sensor Bank 2 Sensor 4

U069D is a communication fault where the engine control module has lost the controller area network signal from the exhaust gas temperature sensor assigned to bank 2, sensor 4. The module detects that the sensor's periodic status message has stopped arriving within the expected time window, so it flags the sensor as offline rather than reporting an out-of-range temperature reading.

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

Symptoms you may notice

  • Illumination of the check engine light or service vehicle soon message with no other obvious change in vehicle behavior
  • Often no symptoms besides the warning light, because the fault is a lost data message rather than a failed sensor reading
  • Reduced engine power or limp-home mode on vehicles that use exhaust temperature data for diesel particulate filter regeneration
  • Inability to complete a forced diesel particulate filter regeneration or an emissions readiness monitor
  • Intermittent warning light that comes and goes with vibration, moisture, or temperature changes
  • A stored freeze-frame showing the fault set during a specific driving condition such as a cold start or a regeneration cycle

Common causes, most likely first

  1. Damaged, chafed, or corroded wiring in the sensor harness between the exhaust gas temperature sensor and its connector
  2. A failed exhaust gas temperature sensor that no longer transmits its controller area network message
  3. Loose or water-intruded connector pins at the sensor or at the harness junction
  4. A poor ground or power feed shared by the sensor circuit, causing the sensor to drop offline
  5. A faulty module or gateway that is not passing the sensor message onto the network
  6. Aftermarket exhaust work or a replacement sensor with an incompatible communication protocol
  7. A controller area network bus fault elsewhere on the same segment that disrupts the sensor's message

How to diagnose and fix it

  1. Scan all modules for communication codes and record freeze-frame data to confirm U069D is current rather than history
  2. Inspect the exhaust gas temperature sensor harness and connector at bank 2, sensor 4 for chafing, corrosion, and pushed pins
  3. Measure sensor supply voltage and ground at the connector with the key on, and check for a short or open on the communication line
  4. Perform a wiggle test on the harness while watching live sensor data or the communication status to expose an intermittent fault
  5. Substitute a known-good sensor of the same part type and clear the code to see whether communication returns
  6. Check for related communication codes on the same network segment that point to a shared bus or module fault
  7. After repair, clear codes and complete a drive cycle that includes the conditions needed to run the exhaust temperature monitor

Why a lost message is not a bad sensor

  • Technicians often replace the exhaust gas temperature sensor first, but a chafed harness near the exhaust or a corroded connector pin causes this code far more often than the sensor itself.
  • U069D reports a missing network message, so the sensor may still be physically intact and reading correctly while its data never reaches the engine control module.
  • A single failed sensor can set this code alongside other communication codes if the sensor shares a network segment with another module, so always scan every module before condemning parts.
  • Aftermarket exhaust components or a sensor with the wrong communication protocol can set this code even though the part fits and the engine runs normally.
  • The code can be stored as history after a low-voltage event or a battery replacement, so verify it is current before starting a diagnostic repair.

Can I keep driving with U069D?

The vehicle usually remains driveable because this is a communication fault rather than an immediate safety failure, but avoid long trips and heavy load until it is repaired. Do not ignore it on a diesel, because lost exhaust temperature data can prevent diesel particulate filter regeneration and lead to a clogged filter.

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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