U061F

Code

Generic U — Network/User

Lost Communication With Exhaust Gas Temperature Sensor Bank 1 Sensor 1

Brand: Generic

Type: U — Network/User

Views: UK: 20 EN: 35 RU: 29

AI status

Completed

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Page language: EN

Causes

Damaged or disconnected EGT sensor (Bank 1, Sensor 1)
Open, shorted, or corroded wiring or connector between the sensor and ECU
Poor ground or power supply to the sensor circuit
Faulty sensor module or harness connector (water intrusion, corrosion)
Intermittent or failed ECU/PCM or peripheral control module
Faults on vehicle data network (CAN/LIN) if the sensor is networked

Symptoms

Malfunction Indicator Lamp (MIL) or check engine light ON
No EGT data displayed on scan tool for Bank 1 Sensor 1
Reduced engine protection strategies or limp-home mode (on some vehicles)
Poor fuel/aftertreatment control, increased emissions, possible regeneration issues
Possible stored network communication faults or multiple U-codes

What to check

Read freeze frame, permanent and related codes with a diagnostic scanner; note intermittent flags
Visually inspect sensor, wiring, and connector for damage, corrosion, or heat damage
Confirm connector is fully seated and locking tabs intact
Check fuses and power/ground circuits related to sensor and ECU
Scan for live EGT data and other module communication status
Backprobe sensor connector to check for reference voltage, signal, and ground while engine cold and after warm-up

Signal parameters

Sensor type: typically thermocouple or thermistor output (analog voltage or mV proportional to temperature) or a networked smart sensor
Analog voltage range commonly seen: approx. 0.1–4.9 V (varies by design); thermocouples produce small mV-level signals
Networked sensors: CAN high/low idle ~2.5–3.5 V and ~1.5–2.5 V respectively (verify manufacturer spec)
Expected behavior: signal voltage/resistance should change smoothly with temperature when heated/cool
No data / out-of-range / static value indicates loss of communication or circuit fault

Diagnostic algorithm

Retrieve all related codes and freeze-frame data. Note whether the code is current, pending, or intermittent.
Perform a thorough visual inspection of Bank 1 Sensor 1, wiring harness, heat shields and connectors for chafing, corrosion, or disconnection.
With a scan tool connected, observe live EGT data (Bank 1 Sensor 1). If no data, attempt a wiggle test on the harness and connector to see if data appears or code sets.
Check supply and ground at the sensor connector: verify battery voltage (if applicable), reference voltage and good ground continuity back to chassis/ECU.
Measure sensor output directly (voltage, mV or resistance per sensor type) while the engine is cold and while warming the exhaust (use safe heat source) to confirm the sensor changes as temperature changes.
Check continuity between the sensor connector and ECU pins; test for shorts to battery voltage or ground. Repair any open/shorted wiring.
If the sensor is a networked device, check CAN/LIN bus integrity: measure CAN-H and CAN-L voltages, check termination resistances and look for other modules reporting communication faults.
If wiring, connector and bus checks are good but the fault remains, replace the EGT sensor and clear codes. Re-scan and perform a test drive to confirm the code does not return.
If code returns after sensor replacement, suspect harness damage in inaccessible area or ECU/module input failure; consider module bench tests or professional module repair/replacement.
After repair, verify proper operation of aftertreatment controls and that no related codes remain.

Likely causes

Broken/chafed wire in harness near exhaust or flex areas
Corroded connector pins at sensor or ECU causing lost continuity
Sensor element failed from heat or contamination
Failed ECU input circuit or internal connector pins
CAN or LIN bus wiring shorted/open or missing termination resistor
Recent repairs or heat shields disturbed the sensor or connector

Fault status

⚠️ Status

Lost communication with Exhaust Gas Temperature Sensor Bank 1 Sensor 1 — ECM not receiving expected signal/data from the upstream EGT sensor. Check sensor, wiring, connectors, and vehicle data network.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.5 hours