P247A: Exhaust Gas Temperature Out of Range Bank 1 Sensor 3

What it means

The EGT sensor at bank 1 sensor 3 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 3 measures exhaust gas temperature at its own point in the exhaust, and the control module checks its reading for plausibility. P247A sets when bank 1 sensor 3 remains outside the expected range, which can indicate a biased or damaged sensor, an electrical connection problem, or a nearby exhaust leak.

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. Record freeze-frame data and compare bank 1 sensor 3 with the other exhaust temperature readings, taking engine load and warm-up into account.
2. With the exhaust cool, locate bank 1 sensor 3 and inspect its connector and harness for heat damage, corrosion, looseness, or contamination.
3. Inspect the exhaust around sensor 3's mounting point for signs of leakage.
4. Observe bank 1 sensor 3 live data through warm-up and changing load to check whether it tracks plausibly against other sensors.
5. Test the sensor and circuit against the manufacturer's specification before replacing the sensor.

Common fixes

• Repair damaged wiring or poor terminal contact at bank 1 sensor 3.
• Repair an exhaust leak near the bank 1 sensor 3 mounting point.
• Replace a contaminated or damaged bank 1 sensor 3.
• Replace bank 1 sensor 3 if it fails the specified plausibility or circuit test.

Can I keep driving?

If the vehicle runs normally, short necessary trips are generally reasonable while you arrange diagnosis. Avoid heavy loads if reduced power occurs, since emissions control and fuel economy may be affected.