A fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.
What you can do yourself
- The control unit uses the catalyst temperature to decide when to inject AdBlue: the catalyst only cleans the exhaust when it is hot.
- First, on your own: inspect the sensor connector and wire near the exhaust pipe — melted insulation, corrosion, water.
- FMI 2, 3, 4, 10 — the sensor, its connector or wiring.
- FMI 15, 16 — the gases at the SCR inlet are too hot: look at the other engine and exhaust codes.
- While the sensor is faulty, AdBlue may not be injected — exhaust cleaning faults (SPN 4364) will follow.
Stop and don’t drive on if:
- The Check Engine light is flashing
- The temperature gauge is in the red or the overheating light is on
- The red oil pressure light is on
- Smoke from under the bonnet, a burning or petrol smell
- Strong jerking, knocking from the engine, or the car barely moves
Add the FMI — the second number of the code. It shows what exactly is wrong with the parameter.
Source: Detroit DDC-SVC-MAN-0084: SPN 4360 (static.nhtsa.gov, MC-10129726)
The explanation comes from the error code reference in the AvtoElektrik PRO app.