What it means
The module detects that the bank 1 sensor 4 exhaust gas temperature reading is outside its expected range or does not respond as expected. It sets the code when the reading fails the calibrated range or performance checks.
How it works
Bank 1 sensor 4 measures exhaust gas temperature, and the control module checks whether its reading is plausible for current operating conditions. P246F sets when that reading falls outside the expected range or does not respond as expected, without proving the sensor itself is faulty.
Common causes
Most likely first.
- Faulty exhaust temperature sensor
- Damaged wiring or connector
- Exhaust leak near sensor
- Sensor contaminated or incorrectly installed
- Control module fault
Symptoms
- Check engine light
- Reduced engine power
- DPF or emissions warning
- More frequent regeneration
How to diagnose it
- Read freeze-frame data and related EGT or DPF codes to see the conditions under which the bank 1 sensor 4 reading became implausible.
- Compare the live bank 1 sensor 4 reading with other EGT readings and operating conditions as described by the manufacturer's diagnostic procedure.
- Inspect the sensor tip, installation, connector, and nearby wiring for contamination, damage, poor contact, or heat exposure.
- Check for an exhaust leak near bank 1 sensor 4 that could make its reading differ from actual exhaust conditions.
- Test the sensor and its wiring for a plausible response using the manufacturer's procedure before replacing parts.
- If sensor and wiring checks pass, investigate abnormal exhaust temperatures and module-related faults indicated by other data.
Common fixes
- Repair a poor connector contact or damaged wiring to bank 1 sensor 4.
- Correct a nearby exhaust leak that is affecting the temperature reading.
- Clean or reinstall the sensor correctly if contamination or poor installation is confirmed and the manufacturer's procedure allows it.
- Replace bank 1 sensor 4 if testing shows it is out of range or unresponsive.
- Investigate a module fault only after the sensor, circuit, and exhaust have been checked.
Can I keep driving?
If the vehicle has normal power and no DPF warning, drive gently and arrange diagnosis soon. Avoid heavy loads if power is reduced or regeneration is occurring unusually often, since inaccurate temperature feedback can interfere with emissions control.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.