P2479: Exhaust Gas Temperature Out of Range Bank 1 Sensor 2

What it means

The EGT sensor at bank 1 sensor 2 reports a value outside its plausible operating range over time - typically a degraded element giving an offset that the substitute logic flags as implausible.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

Bank 1 sensor 2 measures exhaust gas temperature farther along the exhaust system than bank 1 sensor 1, and the control module checks whether its reading is plausible. P2479 sets when bank 1 sensor 2 remains outside its expected range, which may result from a biased sensor, a circuit fault, contamination, or an exhaust leak near this sensor's position.

Common causes

Most likely first.

1. Aged or biased exhaust-temperature sensor
2. Damaged wiring or poor connector contact
3. Sensor contaminated or damaged
4. Exhaust leak near the sensor

Symptoms

• Check-engine light on
• Possible reduced engine power
• Possible increased fuel consumption

How to diagnose it

1. Save freeze-frame data and compare bank 1 sensor 2's reading with bank 1 sensor 1 and other available exhaust temperature readings under similar conditions.
2. With the exhaust cool, inspect the bank 1 sensor 2 connector and harness for damage, corrosion, loose contact, or contamination at the sensor.
3. Check for an exhaust leak around the bank 1 sensor 2 mounting point that could affect the local reading.
4. Watch live data during warm-up and changing engine load to see whether bank 1 sensor 2 responds plausibly relative to the other sensors.
5. Test the sensor and its circuit to the manufacturer's specification, replacing the sensor only if wiring and connections are sound.

Common fixes

• Repair a poor connection or damaged bank 1 sensor 2 wiring.
• Repair an exhaust leak near bank 1 sensor 2.
• Replace a contaminated or physically damaged bank 1 sensor 2.
• Replace bank 1 sensor 2 if its output remains out of specification after circuit checks.

Can I keep driving?

If the vehicle behaves normally, limit driving to necessary trips while arranging diagnosis. Avoid heavy loads if power drops, because the implausible bank 1 sensor 2 reading may affect emissions management and fuel consumption.