P2477Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic (Bank 2 Sensor 4)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2477 targets a signal from bank 2 probe 4 that jumps around, while each individual sample may still be in range. Real exhaust temperature changes only gradually because the probe and pipe have thermal mass, so sudden steps between consecutive readings betray a wiring or contact issue. GM documents the method for the bank 1 sibling P2472: its 2017 diesel table counts samples with a resistance step above 10 ohms and fails at 15 of 30, as a Type B fault with the MIL on the second trip. P2477 itself appears in no public maker document. Faults tend to come and go with vibration or heat, so wiggling the harness while watching live data is the usual way to find them.
- What you may notice
- MIL on after the second faulty trip
- Value of bank 2 probe 4 jumps in live data
- Fault code returns after being cleared
- Likely causes
- LikelyLoose or corroded pins in the probe connector
- PossibleWire strands breaking near the hot pipe
- RareCracked probe element with unstable contact
- 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: €0 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.