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Discussion Starter #1
Hello. DSE, 2000, LHD. I have some problems with ABS, TC lights on. Stop Lights are not working. Diagnostocs show "Brake Switch Fault". I started digging.
Brake Switch is ok, checked it with a multimeter. I started checking the wiring and got stuck. Brake Switch connector has only two wires; RAVE says, it has to have three. My colours are black-red and white-red; RAVE for any model year is sure they have to be white and green-purple. I rewired wires to C1276 connector on the BCEM and stop light started working, but ABS and TC lights are still on and I can't go on checking the wiring because all wiring diagrams are obviously wrong for me.
Is there any other RAVE versions apart from those here? Google Drive - Virus scan warning
 

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Are you sure you've got the correct brake light switch? The switch needs to have two contacts, hence the 3 wires, but if yours just has 2 wires it sounds like it's from an earlier car. Not sure why that would bring the ABS and TC lights on though as if their is no ground signal from the brake light switch, then the ABS and TC won't know there is a problem.
 

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Discussion Starter #3
Are you sure you've got the correct brake light switch? The switch needs to have two contacts, hence the 3 wires, but if yours just has 2 wires it sounds like it's from an earlier car. Not sure why that would bring the ABS and TC lights on though as if their is no ground signal from the brake light switch, then the ABS and TC won't know there is a problem.
It's XKB100170 LAND ROVER switch, I'm pretty sure it's stock. It also has 3 contacts, the connector has three contacts, but only the first and the third wire. I ordered a new switch, it's the best I can do for now.
 

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It's the correct switch but the wiring should have all 3 wires used, even on the diesel version which is often different.
 

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Discussion Starter #5
Well, there is no indication, that the middle contact on my old switch was ever used, there is no marks on it in comparison to the first and third contacts. Anyway, while I wait for a new switch, I started to ring the wires. Below is the scheme. Green means ok, red means a cut wire.
Wires from pedal switch to BCEM c1276 connector were somehow cut, I temporarily rewired them and stop lights started working, but lights on the dash and ABS Fault didn't go away. Everything else I had time to check was ok, apart from a yellow-black wire from ABS ECU to Fuse Box. I rewired it too and ABS Pump started to pump without stopping once on, so I guess there has to be a mistake in the scheme too. Or I just don't know how a relay works)
All that is left is to wait for a new switch, I guess. Though I'm pretty sure that the old one is working too.
 

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On the middle diagram where you are showing red between the relay and the ABS ECU, a ground from the ECU causes the relay to pull in and power the ABS pump. You say it causes it to run without stopping, how long did you leave it for? With a decent accumulator and a system with no pressure in it, then it will run for up to around 40 seconds to build up pressure. Once it has built up pressure the TC light will go out but the ABS light will stay on until you reach 5mph (8kph).
 

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Discussion Starter #7
You say it causes it to run without stopping, how long did you leave it for?
My accumulator is almost new. Pump didn't run after engine start as the sistem was under pressure already, it ran after I pumped brake padal several times and then didn't stop for a minute maybe. It was giving odd noises, so I didn't wait any longer. And lights on dash didn't go away too.
So you are saying that this yellow-black wire should be connected in any case?
 

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Yes, it needs to be connected or the ECU will never operate the relay to cause the pump to run. Odd noises and running for longer than it should is usually a sign that the brake system needs to be bled as it is compressing air bubbles in the fluid as well as the Nitrogen in the accumulator. You must bleed it as per RAVE to get all of the air out.
 

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Discussion Starter #9
Yes, it needs to be connected or the ECU will never operate the relay to cause the pump to run. Odd noises and running for longer than it should is usually a sign that the brake system needs to be bled as it is compressing air bubbles in the fluid as well as the Nitrogen in the accumulator. You must bleed it as per RAVE to get all of the air out.
The interesting thing is the pump runs and braking is almost ok, but without black-yellow wire pump runs every pedal operation. Ok, thanks, I will rewire it and bleed the system. We'll see what happens.
 

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Discussion Starter #10
Could you please explain, why this wire is grounded? It's the second pin of Brake pedal position sensor connector and the other end of it goes to ABS ECU. And why there is a resistor there?
289660
 

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No idea, ask Wabco why make the ABS system. It does say not installed on all vehicles so maybe yours is one that didn't have it?
 

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No idea, ask Wabco why make the ABS system. It does say not installed on all vehicles so maybe yours is one that didn't have it?
Well, I'm sure my car doesn't have it. More than that, my car doesn't have a second pin in Brake Switch connector, I'm pretty sure of it. But I have run out of any ideas: all the wiring somehow associated with ABS is ok (I checked multiple times), ECU gets it's power, ABS pressure sensor is ok, Brake Switch is ok and new and so on. Being desperate, I even added a second pin myself, but it didn't help. As the last reserve, I plan to buy a new ECU tomorrow and see what would happen. After that I guess the last culprit would be a BECM.
 

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Discussion Starter #13
Well, my motto now is to persevere and go on. Changing the ECU didn't help, but I also bought an ABS modulator with that and spent 4 hours yesterday replacing it and bleeding the brakes. And guess what happened! Park light is still on, ABS light goes away after reaching 7 kmph, and TC light is on and blinking as if giving me a message. At least it's a progress, though RAVE has no info TC should blink ever. My idea is to bleed the brakes again some other day. Any thoughts?
 
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