Disco 1 D1 ABS

[basquen]

Hi,
Does anyone have a wiring diagram for the ABS on a 1997 Discovery 300tdi EDC ?
The blink test is giving a 3-1 error "Hydraulic modulator solenoid valve, RH front outlet - ECU connection/wiring"
I need to start with a continuity test on the loom between the ECU and the pump.
Is there a means to cycle this valve by itself ?

 

[sierrafery]

Hi, you can download for free the whole electrical trubleshooting manual from the web just search "Discovery 1 ETM pdf" or see THIS , just read the introducting user guide to know how to corroborate the wire colours and connector views cos it's not very human friendly

 

[basquen]

Thanks ! As you say, not human friendly but I can at least decipher the connector pins and the wire colours.

 

[basquen]

Thanks ! As you say, not human friendly but I can at least decipher the connector pins and the wire colours.

Ok so I've check the continuity of the ECU/ABS loom and all is ok.
So now I need to find a way to test the RH front solenoid valve.

 

[sierrafery]

So now I need to find a way to test the RH front solenoid valve

Find the wire which ges to it from the modulator's connector and splice into it with +12V cos afaik the earth is common for all and if it clicks it should be OK, or find the wire for other solenoid, measure resistance and compare if you see what i mean

 

[basquen]

So just to double check if I'm reading the ETM correctly I need to splice in 12v to the SR grey-red wire that goes between pin 1 on the modulator and pin 6 on the ECU ? (red on screen capture attached)

 

[sierrafery]

Yes, then if no click double check by splicing into the next solenoid's wire to make sure the click is audible(i tried on D2 and i heard it) so if the RHF doesnt click and the other does you know but if no sound on any solenoids compare resistances between ground and those wires and if everything checks out the ECU becomes suspect

 

[basquen]

Thanks for the quick reply!
Just checked all 4 solenoids: unplugged the plug to the ABS ECU and sent direct 12v to the pins #6, #23 #5 #22. All 4 solenoids click correctly in the modulator.
So this confirms that the solenoids operate and the continuity in the ABS ECU <>modulator loom is OK.
I actually have a spare ABS ECU so I've just redone the blink test with both ECU's and I'm still getting the 3-1 error.
Same error with 2 different ECUs so logically not an ECu problem.
Just a thought - to erase the errors I just unplug the jump wire in the OBD socket during the blink process - guess this is correct?
I've read elsewhere that the ABS relay doesn't have to be removed. Being a pain to get hold of I've left it in. Perhaps this prevents erasing the fault ?

 

[sierrafery]

Same error with 2 different ECUs so logically not an ECu problem.

yes seems so, quite strange... then measure resistances and compare cos even if the solenoid works it might have a resistance out of the diagnostic protocol's range, the whole diagnostic guide is attached