The P2689 code indicates that the engine control module has detected a voltage level in the fuel supply heater circuit that is higher than the expected operating range. This typically signifies an open circuit, meaning electricity cannot flow through the heater element.
The internal heating element has burnt out or developed an open circuit, preventing current flow.
Frayed, broken, or severed wires between the control module and the heater assembly.
Moisture or road salt has caused corrosion at the heater plug, creating high resistance or a total break in the circuit.
A blown fuse in the fuel heater circuit prevents the system from receiving necessary power.
An internal failure in the engine control module's driver circuit for the fuel heater.
No, this code generally does not cause a vehicle to stall, although it may lead to fuel gelling and hard starts in freezing temperatures.
No; it is very rare for the PCM to be the cause. The fault is almost always found in the heater element, the wiring, or a blown fuse.
This code is far more common on diesel engines, as they utilize fuel heaters to prevent paraffin wax from crystallizing in cold weather.