DAF XF 105 rear axle modulator internal error

[matt96]

Hi there, I have a DAF XF and recently had two errors appear on the dash…

Red, EBS - Brake system truck warning
Yellow, Transmission warning
Red, STOP warning
And a constant buzzing alarm

The truck with trailer drove fine after the errors appeared to get back home, the only noticeable difference is without the trailer the brakes don’t feel as good, you’re having to push the pedal a lot harder to slow down, no change to the transmission.

Been diagnosed by DAF and have been told that their computer says, rear axle modulator internal error… they suggested that the modulator needs replacing and should be plug and play, we’ve fitted a new modulator ourselves this afternoon and still have the errors, disconnected the battery and have been to the independent garage we usually use and they’ve cleared all the errors but they come straight back on when the ignition is switched on, they also tested all fuses and relays and tried new relays. Have also noticed tonight that the reverse lights don’t work, might be separate problem?

It’s been suggested that the modulator may need programming in or they could be a broken wire somewhere, although the a DAF fitter said it should be a plug and play… if anyone has had a similar problem or came across any broken wires linking to the modulator any advice would be greatly appreciated before we start striping all the wiring off the chassis.

Many thanks

2009
DAF XF 105
Tractor unit
6x2 midlift

[punchy_dan]

It may be that you need to save the code to file off the old unit and put it on the new unit ,that’s what I did on a euro 6 air dryer .

[matt96]

Punchy Dan:
It may be that you need to save the code to file off the old unit and put it on the new unit ,that’s what I did on a euro 6 air dryer .

Was that something you had to get done at a main dealer or could an independent garage do that? They’ve got software that covers all makes of lorries so isn’t as in depth as daf’s

[punchy_dan]

You just need someone with an up to date lap top ,older ones can’t swap codes over .

[matt96]

Good news! The problem has been found! After a few more phone calls and a trip to a garage with ex DAF mechanics in they found out that the original modulator had no faults with it and there was a broken wire in the passager side wheel arch where the cables run about the wheel under the cab, the wires had been rubbing on a bracket and wore through.