VOLVO
ECM-1817 - Engine cooling fan (FC) relay, 1/2 speed. Signal too low
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsS40 (1996–2004), V40 (1996–2004)
Show models by year and engine (2)
What does this fault code mean?
The cooling fan has half and full speed, and half speed is switched by its own relay, which the engine control module (ECM) monitors. If the control signal to that relay is too low, fault code ECM-1817 is set. Cars without A/C only have half speed.
Possible causes
- Control signal wire shorted to ground
- Open circuit in the control signal wire
What you can do
- 1Switch off the ignition and check the connector to the half-speed cooling fan relay in the engine bay relay box for play and oxidation
- 2With a multimeter, check that the control signal wire to the relay is not broken and not shorted to ground
- 3If you have a diagnostic tool: activate the cooling fan at half speed and check that it starts
- 4If the fault remains, have a workshop replace the half-speed cooling fan relay
Symptoms you may notice1
- No noticeable symptoms for the driver
What the fault can affect1
- The cooling fan runs at full speed instead of half speed
General guidance for car owners. Diagnosis on the car can point to a different cause.