U0620Lost Communication With Exhaust Gas Temperature Sensor Bank 1 Sensor 2
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- Sensor 2 on bank 1 is the next exhaust temperature measuring point downstream of sensor 1; on diesels it usually sits ahead of the particulate filter or the SCR catalyst, depending on how the maker numbers its sensors. U0620 is the lost-communication code for this point when it is a digital sensor: its frames have stopped, are too old, or its own diagnosis has switched the SENT output off. GM uses it in the same 2025 diesel tables as U061F with an identical rule (19 bad out of 25 samples at 100 ms, Type A), and again a second code identifies the controller input the sensor is connected to. Monitors and regeneration decisions that need this temperature cannot use it while the link is down. An analog sensor at the same position reports circuit faults as P2031 to P2033.
- What you may notice
- Malfunction indicator lamp in the first trip on GM diesels
- Diesel particulate filter or SCR warnings may follow
- Likely causes
- LikelySignal, supply or ground wire of the sensor damaged near the exhaust
- PossibleMoisture or corrosion in the underbody connector
- PossibleSensor electronics module failed
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.