What it means
Same as P04CF on EGR temperature sensor D. EGR mixes inert exhaust into intake to lower combustion peak temperature — too little raises NOx, too much causes misfires and rough running.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
EGR temperature sensor D reports the temperature of exhaust gas in its part of the EGR system. The control module checks whether the sensor reading changes plausibly as the engine and EGR flow change; it sets P04E6 when the reading is out of the expected range or responds too slowly, rather than simply being consistently low or high.
Common causes
Most likely first.
- EGR temperature sensor drifting or responding slowly
- Loose or corroded connector
- Damaged sensor wiring
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
How to diagnose it
- Use a scan tool to record freeze-frame data and compare sensor D's live temperature reading with other available EGR temperatures and engine temperature to spot an implausible or sluggish response.
- With the engine cool, inspect sensor D and its connector for looseness, corrosion, heat damage, or contamination that could slow or distort the signal.
- Trace sensor D's wiring for cuts, chafing, stretched sections, or heat damage, especially near the exhaust and moving parts.
- Watch the live reading while the engine warms and EGR operation changes, checking for a smooth response rather than a stuck or delayed value.
- Test sensor D and its circuit against the manufacturer's specification to distinguish a drifting sensor from a wiring or connection fault.
Common fixes
- Reconnect and secure sensor D's loose connector.
- Clean or repair corroded connector terminals as appropriate.
- Repair damaged wiring and protect it from exhaust heat or rubbing.
- Replace EGR temperature sensor D if its response fails the manufacturer's specification.
Can I keep driving?
If the engine runs normally and there is no severe knocking, a short, gentle drive to arrange diagnosis is generally reasonable. Avoid heavy load if pinging or power loss occurs, since poor EGR temperature feedback can contribute to high NOx emissions and rough running.
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.