P017ACylinder Head Temperature Sensor A Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- The cylinder head temperature sensor A is an NTC thermistor that measures the temperature of the cylinder head metal or of the coolant in the head. Some Ford engines use it instead of a coolant temperature sensor and calculate a coolant value from it; VW group V8 petrol engines use it as sender G407. CARB requires such sensors to be monitored like the coolant sensor. P017A is the general circuit fault without telling low from high. No manufacturer document using exactly this code was found: VW uses P017B/P017C/P017E for its sensor, and Ford's summaries list its own codes. Ford's published summaries still use its own codes P1289/P1290 for this sensor (fault below 0.244 V or above 4.96 V for 5 s). The description rests on CARB and component information. On a sensor fault the control module typically uses a modelled temperature and runs the radiator fan.
- What you may notice
- Check engine light on
- Coolant temperature warning or wrong gauge reading
- Radiator fan runs loud or constantly
- Cold-start problems possible
- Likely causes
- LikelyWiring or connector open or corroded
- PossibleSensor faulty (moisture in the housing)
- RareEngine control module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €50 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.