U0901Invalid Data from Ion Sense Module
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- An ion sense module evaluates the tiny current that the burning mixture conducts between the plug electrodes after ignition for the engine controller, which uses it to spot misfire, knock and poor combustion; Ford's patent US20170030322A1 places such a module in the ignition system. U0901 means the module's messages still arrive but their content is rejected – a value out of range, an implausible signal or a wrong checksum or counter. No manufacturer documents U0901 publicly. Stellantis' 3.0 L Hurricane six runs a networked ion sense system: its bulletins name U0673 (module silent) and P2F64 (ion sense feedback circuit A), both cured by PCM software. Saab's Trionic T8 module still fed knock and combustion pulses to the controller over separate wires. With bad ion data, misfire and knock detection lose their basis.
- What you may notice
- Check engine light
- Possibly reduced power from knock protection
- Misfire or ion sense codes stored alongside
- Likely causes
- LikelySoftware of the engine controller or ion sense module (update available)
- PossibleDisturbed data line, for example from ignition interference or a poor ground
- RareIon sense module internally faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.