P24C2: Exhaust Gas Temperature Measurement System - Multiple Sensor Correlation Bank 1
What to do
Mention any exhaust work the car has had, however minor. This code says the temperature sensors along the exhaust disagree with each other, and a sensor refitted in a slightly different position after a repair is a common and entirely mechanical cause.
Expect diagnosis to take a little time. The code names the disagreement rather than which sensor is wrong, so the garage has to compare readings from all of them — usually starting from cold, which may mean leaving the car overnight.
The car will generally drive normally, though it may attempt particulate filter regenerations more often than it should, which shows up as worse fuel consumption.
What this code means
The exhaust gas temperature sensors on bank 1 disagree with one another by more than they should.
A correlation code names a relationship rather than a component, and that is what makes it distinctive. No single sensor is out of range. They are individually plausible and collectively impossible — and the module knows the exhaust well enough to say so.
The test is usually done when the exhaust should be uniform, typically after a long soak with the engine off. At that point every sensor in the pipe should read close to ambient and close to each other. One that reads twenty degrees warmer than its neighbours after standing overnight has drifted, and the module needs no running data to prove it.
The awkward part is that the code names the system, not the culprit. Identifying which sensor drifted needs live data from all of them, compared at a known condition.
Do not assume the sensor is faulty just because it is the odd one out. A sensor reading differently because it sits in a different place — moved during an exhaust repair, or in a pocket rather than the gas stream — is mechanically misplaced rather than electrically failed.
Wiring resistance produces the same picture. A corroded terminal on one sensor shifts its reading consistently, which looks exactly like drift until the connector is inspected.
Likely causes
Start here
- Sensor drifted out of calibration · moderate
- High resistance in sensor wiring · moderate
Less common
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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