What it means
A general circuit fault is detected on the EGT sensor at bank 1 sensor 4 (typically just downstream of the turbo or before the catalyst). The ECU loses thermal protection feedback for the catalyst and DPF.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bank 1 sensor 4 is an exhaust gas temperature sensor that reports temperature at its location in the exhaust system. P246E sets when the module detects an open or other circuit fault in that sensor's circuit and loses reliable temperature feedback for emissions-system control.
Common causes
Most likely first.
- Open or damaged wiring to the sensor
- Loose or corroded connector
- Faulty exhaust gas temperature sensor
- Blown fuse or power/ground circuit fault
Symptoms
- Check engine light on
- DPF or emissions warning light may come on
- Reduced power or limited regeneration may occur
- Increased fuel consumption
How to diagnose it
- Read freeze-frame data and related EGT or DPF codes to identify when the bank 1 sensor 4 circuit fault occurred.
- Locate bank 1 sensor 4 using the vehicle's service information and inspect its connector and nearby wiring for looseness, corrosion, melting, or breaks.
- Check the sensor harness routing and look for damage where it passes near hot exhaust components.
- Test the bank 1 sensor 4 circuit for an open, poor connection, or power and ground fault using the manufacturer's wiring diagram and procedure.
- Test the sensor itself against the manufacturer's specification before replacing it.
- After repairs, clear the code and confirm the bank 1 sensor 4 reading responds plausibly on a scan tool.
Common fixes
- Reconnect or clean a loose or corroded bank 1 sensor 4 connector.
- Repair an open or heat-damaged section of the sensor wiring.
- Repair a confirmed fuse, power, or ground fault in the sensor circuit.
- Replace bank 1 sensor 4 if circuit testing confirms the sensor has failed.
Can I keep driving?
If the engine runs normally, a short, gentle trip to arrange diagnosis may be possible, but avoid heavy loads and prolonged high-speed driving. Missing bank 1 sensor 4 temperature feedback can limit regeneration or emissions protection and may lead to reduced power.
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.