Relay or fuse problem??

[darreningram]

Car is W124 E280 5 speed auto- when driving the ABS light comes on and seconds later the car automatically changes into 3rd gear and the cruise control stops working? This lasts maybe 20 seconds then the car changes back into appropriate gear and the light goes off- the cruise control still doesn't work though?! This has happened twice. After I stop and restart the car the cruise works again. Car has had wiring loom changed. I am wondering if relay Is playing up or a fuse needs cleaning. Any ideas appreciated?

 

[DieselPete]

If the cruise control stops working then i would think its logged a fault, this is pure guess work but if the abs light comes on it sounds like the car is loosing its speed signal or the signal is being corrupted and thats whats telling the transmission to change down. I would get it plugged in and codes read. If this dont shed much light then a drive with live data being recorded may also help to find the cause. I very much doubt that a relay or fuse will cause this problem imo but i could be wrong. More likely abs sensor/ wiring to the sensor or even a reluctor ring on hub/drive shaft pls let me know how you get on, good luck

 

[dinoy]

cruise in w124 is set up, if u press brake paddle it switches off. u need to get to write speed again and press cruise paddle.

w124 codes not very easy as it was first of the ecu but not as complicated as later models

abs light dieselpete said could be sensor, but abs unit does go wrong and can be replaced but before going to big expense.

cruise is just that should only change speed if going up or down hill. not sure u need to drive in level road and see if it occurs check sensors.

if neither could be cruise controller or abs then if u know somebody who has one swap them to identify problem.

hope not main ecu and wiring loom problem

 

[darreningram]

I may have confused matters- it doesn't happen when the Cruise is on- it was an incidental finding that it wasn't working after- the first thing is the ABS light goes on and the car changes down 2 cars- then after 5-10 secs goes back to normal

 

[dinoy]

if that is the case then means abs is applying, check brakes n sensors could ABS ecu or ABS control unit. again if u can access code might shed light.

but not easy best find reputable INDY he might have code reader n things to swap and test

where r u based so members can recommend somebody local

 

[darreningram]

Thanks for the help- based in Northern Ireland which is part of the problem- not many choices! Has anyone tried the new specialist in Banbridge- German Motor Works??

 

[dinoy]

if u know anywhere u can access abs ecu (frpm another car owner), if that is ok then u r into the ABS unit to take out fit a replacement might expensive unless u can steal from from scrappy or ebay.