S40: phase one abs probs

[pandollar]

have volvo s40 phase one,the abs light stays on.no codes in the ecu so assume light circuit is earthing out somewhere.found a wiring diagram which implied terminal 13 of the ecu was light circuit,cut this wire under air box[before wires under rad]and light stayed on ,so not that wire.wiring on ecu multiplug implies that terminal 21[brown and black] is the wire as this makes a contact in the multiplug when unplugged[abs failsafe] this wire however does not appear under loom going to bulkhead under the airbox,is there a multiplug i cant see somewhere where the wire changes colour? hope someone can help

[pandollar]

Anyone!

[pandollar]

Does on one have any ideas on this, my MOT is due next month and really need to get it fixed.

[KBB]

If the are no codes then I would be looking at checking all powers and grounds to the ABS ECU. If the ECU has not powered up it cannot give a fault code nor can it send back a self check completed signal to put the dash light out.

[pandollar]

all powers and earths are present as far as my wiring diag shows,which leads me to think a problem with light circuit not ecu

[Clan]

Originally Posted by pandollar

all powers and earths are present as far as my wiring diag shows,which leads me to think a problem with light circuit not ecu

are you aware that there are 2 live feeds and earths at the ecu plug? check both .. The most likely cause for this is a corroded feed wire to the ecu in the loom under the radiator . Volvo did a repair kit which meant running new wires from the ABS fuse in the fusebox across the front and joining them at the ecu plug ...