U068E

Code

Generic U — Network/User

Lost Communication With EGR Temperature Sensor B

Brand: Generic

Type: U — Network/User

Views: UK: 20 EN: 43 RU: 25

AI status

Completed

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Page language: EN

Causes

Open or shorted sensor wiring or connectors (EGR Temp Sensor B circuit)
Failed EGR temperature sensor (B)
Poor sensor power or ground connection
Intermittent connector contact from heat or vibration near the EGR system
Faulty or misconfigured ECU/module (communication interface)
CAN/LIN bus fault or excessive network errors preventing delivery of sensor data

Symptoms

Malfunction Indicator Lamp (MIL) or warning lamp illuminated
Stored U068E fault and possibly related communication codes
EGR system faults, reduced or disabled EGR operation
Poor idle, reduced performance, or drivability complaints if EGR is disabled
Failed emissions test or increased exhaust temperatures if EGR inactive

What to check

Read and record all stored codes and freeze frame data with a scan tool
Check for other U-codes or module communication faults on the network
Visually inspect sensor, connector and wiring for heat damage, corrosion, or chafing
Verify sensor connector is fully seated and pins are not bent or pushed out
Check for proper sensor power and ground at the connector (reference voltage and ground continuity)
Monitor live EGR temperature B data (and EGR A if present) while key ON/running

Signal parameters

Sensor signal typically within 0–5 V range to the ECU (varies by manufacturer)
EGR temperature sensor is often an NTC thermistor: resistance decreases as temperature rises (typical resistance range spans ~1 kΩ to 100 kΩ depending on design)
Expect EGR temperature change on live data when applying heat/cold to sensor (slow response relative to intake air sensors)
CAN bus nominal voltages: single-wire CAN_H/CAN_L idle voltages near mid-rail; watch for CAN errors or loss of message IDs if communication-related
No valid temperature value, a fixed out-of-range value, or erratic/fluctuating readings indicate fault

Diagnostic algorithm

Connect a scan tool, confirm U068E and record freeze frame and related codes.
Verify whether EGR temperature B data appears on the network. Note if value is constant, stuck, out of range, or missing.
Inspect connector and wiring from the sensor to the ECU for heat damage, corrosion, pin push-out or shorts; repair or replace as needed.
With ignition OFF, measure resistance of the EGR temp sensor B at the connector (or remove sensor). Compare to expected thermistor behavior: resistance should change when warmed/cooled.
With ignition ON, verify reference voltage/pull-up and ground presence at the sensor connector. Check for short to battery or ground.
Back-probe sensor signal while warming/cooling it (heat with heat gun carefully or cool with canned air) to confirm signal voltage/resistance changes and that the ECU sees the change on the scan tool.
Perform continuity checks between sensor connector and ECU pins to rule out open/short; repair harness if needed.
If wiring and sensor test good but communication still lost, check CAN/LIN bus integrity (termination resistors, other modules, bus voltage, error counters).
If all circuit and bus checks pass, consider replacing the EGR temp sensor B. If issue persists, investigate or replace the ECU/module or reprogram per manufacturer guidance.
After repairs, clear codes and perform a road/test cycle to confirm the code does not return.

Likely causes

Damaged/shorted wiring harness to EGR temp sensor B (heat/exhaust area)
Corroded/loose sensor connector or terminal
Failed EGR temperature sensor B (open or out-of-spec resistance)
Loss of sensor reference power or ground
Module communication fault or CAN bus termination problem

Fault status

⚠️ Status

The controller has detected a loss of communication or invalid signal from the EGR Temperature Sensor B circuit. The sensor data is missing, out of expected range, or the communication message is not being received reliably.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours