P2687Fuel Supply Heater Control Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- Diesel engines warm the fuel at the filter so that wax crystals do not block it in frost. P2687 says the control line of that heater is open. In GM's diesel ECM tables the engine computer switches the heater relay with a low-side driver and judges the off-state voltage; more than 200 kOhm between pin and ground means open. The 2014 version (14OBDG04) needed 11 V for 3 s and 2 s of fault, Type B with MIL; the 2017 and 2020 versions use 10 bad readings out of 20 at 100 ms and rate it Type C without lamp. Ford used the same code differently: its 2015 and 2016 diesel summaries apply P2687 to the vaporizer glow plug of the 3.2 L Transit's downstream injection, open if the line sits at 2.9 to 3.2 V for 5 s; from 2017 that fault moved to P269B.
- What you may notice
- Hard starting or stalling in severe cold
- Power loss from a waxed fuel filter
- Often no warning lamp, depending on model year
- Likely causes
- LikelyHeater relay coil open or relay not seated
- PossibleBroken control wire or corroded terminal at the filter housing
- RareHeater element open where it is switched directly without a relay
- 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 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.