P2689Fuel Supply Heater Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2689 is logged when the fuel heater control line stays high even though the controller has commanded it on, so the relay coil is fed from battery positive and cannot be pulled in; the heater never works. GM's diesel ECM checks the low-side driver in its on state and treats 0.5 ohm or less to power as a short; the 2020 table uses 10 of 20 samples at 100 ms and Type C without lamp or message, while the 2014 table sets it as Type B. Ford's 2015 and 2016 diesel summaries give the code two jobs on the 3.2 L Transit: a vaporizer glow plug line held in the 10.9–12.32 V band for 5 s, and a relay status that contradicts the request for about 60 s, marked as provisional. In 2017 Ford split those into P269E and P26A0. Cold-weather starting is the main thing at risk.
- What you may notice
- No fuel heating, gelling risk below freezing
- Hard cold starts and rough idle until warm
- Warning lamp only on some model years
- Likely causes
- LikelyControl wire shorted to a battery-fed wire
- PossibleHeater relay sticking so feedback no longer matches the command
- RareLow-side driver in the engine controller defective
- 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: €30 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.