P017B code meaning
Cylinder Head Temperature Sensor A Range/Performance
Powertrain system Generic code P01xx codes Check engine light
What P017B means
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 gasoline engines use it as sender G407. CARB requires such sensors to be monitored like the coolant sensor. P017B means the signal is electrically valid but implausible – for example it does not fit other temperature sensors after a long standstill or does not rise as expected. Audi documents it on 2019–2021 V8 TFSI models and Bentley on V8 models from 2018 onwards, together with a cooling system fault code and a red coolant warning: a damaged O-ring at the sensor tip lets water into the housing and damages the sensing element, often intermittently; the fix is a new sender. GM lists P017B only as an exclusion condition in its diesel software. Thresholds are not public.
P017B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P017B
- Check engine light on
- Red coolant warning or overheating warning
- Radiator fan runs loud or constantly
- Possibly reduced power
Common causes of P017B
- Most likelySensor damaged by moisture (O-ring)
- PossibleGenuine temperature problem (air in cooling system, thermostat)
- PossibleContact resistance at the connector
- Less likelySoftware or calibration
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cylinder head temperature sensorSensor wiringCooling system
What each part of P017B means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1 | Area: fuel and air metering. |
| 7B | The exact fault in that area. |
What to do next
- Note P017B and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P017B
What does P017B mean?
P017B means "Cylinder Head Temperature Sensor A Range/Performance". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P017B?
Drive gently and only to a workshop. With P017B the car can go into limp mode (reduced power) to protect itself.
Will P017B fail an emissions test?
Yes, it can. P017B is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P017B to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P017B clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.