P011B
Engine Coolant Temperature/Intake Air Temperature Correlation
Fuel & air metering
Generic OBD-II
Low
What it means
P011B means the engine coolant temperature and intake air temperature sensors disagree by more than expected — after the car has sat cold, both should read close to ambient. It usually points to one sensor drifting out of range, which can throw off cold-start fueling but rarely leaves the car undriveable.
Low
Can I keep driving? Yes — it's usually one temperature sensor drifting; the car runs, though cold starts and warm-up may be slightly rough until it's fixed.
Common symptoms
What you'll notice
- Check-engine light on
- Rough or hard starting when cold, from a wrong temperature reading
- Slightly reduced fuel economy
Common causes
Most likely first
- Faulty or drifting intake air temperature (IAT) sensorLikely
- Faulty or drifting engine coolant temperature (ECT) sensorCommon
- Poor connection or damaged wiring at either sensorCommon
- A genuine cooling fault (e.g. stuck thermostat) skewing one reading before a cold startLess often
How to diagnose & fix
Work through it in order
- After the engine has sat overnight, compare IAT and ECT readings on a scan tool — cold, they should be close.
- The sensor whose reading is furthest from ambient is usually the faulty one.
- Inspect that sensor's wiring and connector, then replace the drifting sensor.
- Confirm the engine actually reaches normal operating temperature (thermostat OK).
- Clear and retest.
FAQ
Quick answers
Is it safe to drive with P011B?+
Yes. This code just means two temperature sensors disagree; the engine runs, though a wrong cold reading can make cold starts and warm-up slightly rough.
Can I just clear P011B?+
It comes back once the ECM compares the two sensors again. The drifting sensor has to be identified and replaced.
Related codes
Often seen with P011B
Read & clear P011B 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