What it means
The module detects a low signal from the bank 1 sensor 4 exhaust gas temperature sensor circuit. The code identifies a circuit signal fault, not a confirmed low exhaust temperature.
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 measures exhaust gas temperature, but P2470 concerns the electrical signal from that sensor. The module sees the signal as low; this points to a circuit condition such as a short to ground or sensor fault, not necessarily genuinely low exhaust temperature.
Common causes
Most likely first.
- Signal shorted to ground
- Faulty sensor
- Damaged wiring or connector
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 codes to see when the bank 1 sensor 4 signal went low.
- Check the scan-tool reading for bank 1 sensor 4 and compare it with other EGT readings under similar conditions.
- Inspect the sensor connector and wiring for chafing, melted insulation, corrosion, or a wire contacting ground.
- Test the bank 1 sensor 4 signal circuit for a short to ground and check the connector terminals using the manufacturer's wiring diagram.
- Test the sensor against the manufacturer's procedure to distinguish a failed sensor from a harness fault.
- After repair, confirm the signal changes plausibly as the exhaust warms.
Common fixes
- Repair a signal wire that is shorted to ground or rubbed through.
- Clean or repair corroded or damaged connector terminals at bank 1 sensor 4.
- Replace the sensor if its signal remains low during the specified circuit test.
- Repair any related wiring or connector fault found during circuit testing.
Can I keep driving?
If the vehicle runs normally, drive gently and have the fault checked soon; avoid heavy loads if a DPF warning or reduced power appears. The low signal can disrupt regeneration control and emissions protection even when exhaust temperature is normal.
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.