P040E
EGR Temperature Sensor A Circuit Intermittent/Erratic
EGR (emissions)
Generic OBD-II
Medium
What it means
P040E means the "A" EGR (exhaust gas recirculation) temperature sensor is sending an intermittent or erratic signal. This sensor monitors the temperature of recirculated exhaust for emissions control, so the fault mainly sets the light and can cause an emissions-test failure — usually from a loose connector or intermittent wiring rather than the engine itself.
Medium
Can I keep driving? Drivable — this is an emissions sensor, so the engine runs, but you may fail an emissions test and see occasional pinging under load.
Common symptoms
What you'll notice
- Check-engine light on
- Often no obvious drivability change
- May fail an emissions/readiness test
- Occasional pinging under load if EGR operation is affected
Common causes
Most likely first
- Corroded or loose connector at the EGR temperature sensor A (intermittent contact)Likely
- Chafed or intermittently shorting wiring in the sensor circuitCommon
- Faulty EGR temperature sensor ACommon
- Poor sensor groundLess often
- ECM fault (rare)Less often
How to diagnose & fix
Work through it in order
- Wiggle-test the EGR temp sensor connector and harness while watching the reading for dropouts.
- Inspect the wiring for chafing, corrosion, or a loose pin.
- Compare the sensor's resistance/reading to spec at known temperatures.
- Replace the EGR temperature sensor if it reads erratically, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P040E?+
Yes — it's an emissions monitoring sensor. The main downside is a possible emissions-test failure, so repair it before testing.
Can I just clear P040E?+
An intermittent fault will return once the loose connection or wiring acts up again. Fix the circuit first.
Related codes
Often seen with P040E
Read & clear P040E yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX