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. P017D means the signal voltage is too high – the sensor or wire is open or shorted to voltage, and the control module would read an implausibly cold head. Ford's published summaries flag this under its own code P1289 above 4.96 V for 5 s, but a 2019 bulletin for the F-150 and Mustang 5.0 litre names P1289 and/or P017D and replaces the sensor – so at least that calibration also sets the generic code. GM lists P017D only as an exclusion condition in its diesel software. The engine uses substitute values; the radiator fan typically runs constantly.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Symptoms
- Check engine light on
- Temperature gauge cold or missing
- Radiator fan runs constantly
- Cold-start or idle problems possible
Most likely causes
- Sensor faulty (series fault on Ford 5.0 litre 2019)
- Connector unplugged or corroded, wire open
- Signal wire shorted to voltage
- Engine control module
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
- It affects emissions.
What each character of P017D means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 1: Air and fuel
- 7D: Specific fault in that system
Frequently asked questions
Can I keep driving with code P017D?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P017D?
The most common causes are: sensor faulty (series fault on Ford 5.0 litre 2019); connector unplugged or corroded, wire open; signal wire shorted to voltage.
Related codes
- P017ACylinder Head Temperature Sensor A Circuit
- P017BCylinder Head Temperature Sensor A Range/Performance
- P017CCylinder Head Temperature Sensor A Circuit Low
- P017ECylinder Head Temperature Sensor A Circuit Intermittent/Erratic
- P0118Engine Coolant Temperature Sensor 1 Circuit High
Sources
- law.cornell.edu: 13 CCR 1968.2
- static.nhtsa.gov: MC 10159452 0001
- fordservicecontent.com: OBD Operations Summary Gasoline 2020 2023
- gsi.ext.gm.com: 16OBDG04 Engine Diagnostics
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.