P2479 indicates the exhaust gas temperature (EGT) sensor for Bank 1 Sensor 2 is reporting a value outside the expected operating range, or its circuit is sending an implausible signal to the engine control module. Note: SAE definitions commonly assign P2479 to Bank 2 Sensor 1; the diagnostic logic is the same regardless of which specific EGT sensor position is flagged. The code usually points to the sensor, its wiring, or abnormal exhaust temperatures rather than the engine computer.
The EGT sensor element or internal circuitry can drift, short, or open with age and heat cycling, producing an out-of-range signal. This is the single most common cause.
High exhaust heat can damage the sensor harness, causing opens, shorts to ground/power, or high resistance in the signal or reference circuits.
A leak upstream of the sensor can draw in ambient air and lower readings, while a downstream restriction can raise them, pushing the reported temperature out of range.
A clogged diesel particulate filter, faulty regeneration strategy, or turbocharger issue can create genuinely abnormal exhaust temperatures that the sensor correctly reports as out of range.
PCM/ECM internal failure causing a misread EGT circuit is uncommon. It should be considered only after the sensor, wiring, and exhaust system have been verified.
Short trips are usually possible, but prolonged driving is not recommended. The vehicle may enter limp mode, and incorrect temperature feedback can damage the turbocharger or aftertreatment system.
Usually no. The failed component is most often the EGT sensor or its wiring. PCM replacement for this code is rare and should only follow verified sensor, harness, and exhaust testing.
No. An EGT sensor measures exhaust gas temperature, while an oxygen sensor measures oxygen content. They perform different jobs and are not interchangeable.
Clearing the code may turn off the light temporarily, but the underlying sensor, wiring, or exhaust fault will typically bring the code back once the monitor runs again.