U0620

Code

Generic U — Network/User

Lost Communication With Exhaust Gas Temperature Sensor Bank 1 Sensor 2

Brand: Generic

Type: U — Network/User

Views: UK: 39 EN: 51 RU: 40

AI status

Completed

ready

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Page language: EN

Causes

Open or shorted EGT sensor wiring or damaged connector
Corroded or loose connector pins at sensor or PCM
Failed EGT sensor (thermocouple or RTD)
Poor or missing power, ground, or reference circuit for the sensor or associated harness
Faulty PCM or other module that receives/relays the sensor data
Intermittent CAN/LIN bus or module communication fault (if sensor data is sent digitally)

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
No or implausible EGT data for Bank 1 Sensor 2 in scan tool/live data
Reduced engine performance or entry into limp mode if PCM lacks EGT inputs
Elevated emissions or failed emissions readiness
Possible diagnostic trouble codes for related systems or communications

What to check

Read freeze frame and full DTC list with a scan tool; note related communication codes
Verify presence/absence of EGT Bank 1 Sensor 2 data on live-data stream
Compare readings from other EGT sensors (Bank 1 Sensor 1 or Bank 2 sensors) for plausibility
Inspect sensor connector and wiring for damage, corrosion, heat damage, rodent chew
Perform wiggle test on harness and connector while monitoring live data for intermittent changes
Check fuses, relays, and power/ground circuits for the PCM and sensor systems

Signal parameters

EGT sensors are commonly thermocouples (millivolt-level output) or resistive temperature devices (ohms) — output increases with temperature
Typical thermocouple output: very low mV at ambient, increasing into tens of mV at high exhaust temps (exact values vehicle-specific)
Typical resistive/voltage-type sensors: may produce a 0–5 V signal or change resistance with temperature (vehicle-specific)
A true open circuit will show no signal or a floating/invalid value; a short to ground or battery will show a fixed low/high reading
Communication-bus failures will show missing or stale packets on CAN/LIN diagnostics rather than an analog invalid voltage

Diagnostic algorithm

Connect a professional scan tool. Record U0620, freeze frame, and any other active or pending codes. Check live EGT Bank 1 Sensor 2 data for presence/staleness.
Inspect sensor and harness visually for heat damage, breaks, pin corrosion, or connector issues. Repair any obvious damage.
If available, compare the suspect sensor data to other EGT sensors. If all data from that sensor is absent/stale, proceed to wiring checks.
With ignition on (engine off) backprobe the sensor connector and measure reference voltage/ground continuity and signal circuit. Refer to vehicle wiring diagram for expected values. Look for open, short-to-ground, or short-to-voltage.
Perform a continuity check between the sensor connector and PCM connector for signal, power, and ground circuits. Repair any wiring faults found.
If the sensor is a thermocouple, check connector bias circuits per manufacturer procedure; if resistive/voltage type, measure sensor resistance or output while heating the sensor (hot air gun or controlled heat source) to confirm response.
If the harness and signals are good but no valid data is present, verify CAN/LIN bus health (bus voltages, message presence) and check for other module comm faults that may affect the EGT data.
If testing indicates the sensor is defective, replace the EGT Bank 1 Sensor 2 and clear codes. Retest for code return and correct data behavior.
If replacing sensor does not fix the code and wiring/bus checks are good, consider module reprogramming or replacement only after confirming module failure with manufacturer diagnostics.

Likely causes

Wiring/connector fault between EGT Bank 1 Sensor 2 and the PCM (most common)
Sensor element failed from heat damage or contamination
Connector corrosion or water intrusion causing intermittent/no signal
Module communication bus error or module internal fault (less common)

Fault status

⚠️ Status

Lost Communication With Exhaust Gas Temperature Sensor Bank 1 Sensor 2 — PCM has not received valid EGT input from Bank 1 Sensor 2. Diagnostic routines flagged missing or invalid data and set DTC U0620. Further inspection of sensor, wiring, connectors, and communication bus is required.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-3 hours