2014 Citroen dispatch ABS Fault C0040

[Monger]

Hello, new to working on newer French cars.
Trying to fix my mums 2014 Dispatch.

So I picked up a scanner that works with the van.

I'm getting a C0040 Code "brake pedal switch fault coherence with the pressure sensor coherence"

Light doesn't come on till I release the handbrake and press the brake pedal, brake lights still work.

When I press the pedal I get "ESP ASR system faulty" "ABS System faulty" "STOP"

I would like to try and fix this myself, but I'm used to working on pre OBD and classic BMWs.

Thanks alot.

Vin is VF7**************[VIN obfuscated, can be read by forum staff]

What would be causing this?

[Monger]

After going through the raw data it seems I have a brake pressure reading that looks correct, wheel speed all looks correct, accel pedal looks correct but the clutch pedal position is reading 0% when I press it down.

Should I replace the brake switch or is it the clutch position?

[RichardW]

Either the brake light switch is faulty or there's a fault in the ABS module. Check on live data for the brake pressure and the status of the brake light switch to see what's happening.

[Monger]

I get a good reading from the brake light switch and brake pressure. Should I replace the abs module?

[GiveMeABreak]

Not without further checks - they are expensive and will require configuring / coding.

C0040: Brake pedal switch fault: Coherence with the pressure sensor.

If you are getting ABS warning lights and the above fault, it's very likely to be the brake switch - this fault is also recorded in several bulletins for other models.

I'd suggest getting it replaced as it's certainly the cheapest option and also because it may be intermittently causing the issues.

[Monger]

Fixed

[Paul-R]

What was the fix?

[Monger]

Brake pedal switch.

[GiveMeABreak]

Thanks for taking the time to update the thread - it will help others.