P2466: Exhaust Gas Temperature Sensor Circuit — Bank 2 Sensor 3
What to do
One thermometer down rarely changes how the car drives, but the stage it brackets is now supervised half-blind — regenerations and dosing run conservative until it is fixed. Heat-damaged wiring along the exhaust leads the suspects, as across this whole chain.
What this code means
The third exhaust temperature sensor on bank 2 has failed its circuit checks — and the number is the news: an exhaust with five numbered thermometers per bank is a map of everything hanging off a modern diesel.
The aftertreatment is a train — oxidation catalyst, then particulate filter, then the reduction catalyst with its dosing — and every stage's chemistry has a working window: the oxidation catalyst must be hot enough to light regeneration fuel, the filter hot enough to burn but not melt, the reduction stage warm enough to convert without crystallising its urea. So sensors bracket each stage, numbered in flow order down the pipe: 1 and 2 are the turbo-and-filter-era pair the corpus met at P0544 and P2080; 3, 4 and 5 arrived with the longer train, typically around the filter's outlet and the reduction stage. Which stage each number brackets varies by layout — the flow-order rule is the constant.
Everything the earlier families established travels: circuit codes are electrical, the heat-baked harness leads the suspects, and the whole chain shares one free plausibility check — stone cold, every sensor should read ambient, so the odd one out convicts itself before a single connector is opened.
Likely causes
Start here
- Exhaust heat damage to sensor harness · moderate
- Open circuit in sensor wiring · moderate
Less common
- Faulty exhaust gas temperature sensor · moderate
Symptoms
Components involved
Information, not instruction
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Community experience
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