Brake and traction control light remaining on

2223 Views 10 Replies 8 Participants Last post by Richard_G, Oct 15, 2018

Alan Lindsay

Discussion Starter · Oct 12, 2018

Hi all,
ive been silent on the forum for ages primarily because the 97 4.6 HSE has been performing faultlessly
I had a major foot surgery three months ago and wearing a 'moon boot' the Rangey has become my primary transport rather than for occasional use and boat towing only as it is spacious in the footwell.
Since I've had her the brake warning light and traction control warning light have remained illuminated on the dash for 30 seconds after start up. In all other ways the brakes have been perfect.
Recently the time to extinguish has increased greatly up to some minutes. For the majority of the time there is no brake boost available. After a period of time the boost is restored and some time later the brake light is extinguished followed by the TC light a second later.
i note that rapid pumping of the brakes will result in the warning lights coming back on.
The vehicle does not use brake fluid, the level in the reservoir remaining constant.

It seems to me that there is some kind of a pressure leak in the system.
can anyone advise of possible causes or a path to identify the problem. I am not familiar with this system
Many thanks
Alan:roll:

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1 - 11 of 11 Posts

xrav22

· #2 · Oct 12, 2018

I am not an expert in the abs systems but I noticed my pedal was harder to stop the car in the morning
and I was advised by a friend to change the brake accumulator. It is the round thing filled with nitrogen that helps the abs. He said hea had the lights and they went away after he changed it. I did it and it solved my
minor problem too. They don't laast forever so if yours is like 20 yrs old I am sure it has lost charge.
Good Luck

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stevesal

· #3 · Oct 12, 2018

Definitely looks like your ABS accumulator is on the way out, the increase in time to pump up is the clue.

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DaGlitch

· #4 · Oct 12, 2018

I 2nd your problem being the accumulator. More specifically, the round tank that screws on to it. If I were you, I would replace it as soon as you can (with a brand NEW one STC2784). Otherwise, you'll have even more expensive issues when the pump goes out from too much stress and constant pumping.

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Richard_G

· #5 · Oct 12, 2018

I'd disagree I'm afraid. The accumulator stores fluid under pressure against a diaphragm with high pressure Nitrogen behind it. They fail when the Nitrogen leaks out so the fluid can't be stored which causes the pump to only run for a few seconds. It also causes the pump to start up again as soon as you touch the brake pedal and the lights come on then as the pressure drops too low. The pump running for much longer suggests a weak pump so it is taking far longer than it should to build up pressure.

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TheoR

· #6 · Oct 12, 2018

I agree that it's most likely not the accumulator that is the culprit.

Most likely, your ABS pump is dying. It's the actual motor that powers the ABS. I've had mine die on me, and pretty much had the same result you had, which is to say that you have absolutely no brake assist and lights stay on.

Chances are, your pump is working intermittently, giving you occasional pressure.

It would be costly to replace the entire ABS pump unit, but it is possible to have the ABS pump motor rebuilt. That's precisely how I resolved my issue. Fortunately, I was able to have the pump rebuilt for something like $75-100, if I remember correctly.

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Richard_G

· #7 · Oct 12, 2018

If it's intermittently working, check the ABS pump relay (RL17). It's a high current dual pole one but has only 4 pins so could have been swapped for one of the lower power yellow ones.

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mad as

· #8 · Oct 13, 2018

ok Alan things to do , go out and turn the key to on not start , time how long it takes for the abs pump to stop (35 to 45 seconds )is normal , then push on brake peddle and count how many time it takes for the pump to start again 3 or 4 pumps is good . if its once or twice its the accumulator possibly . if the pump runs for longer it possibly the pump.

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jamdot

· #9 · Oct 13, 2018

Hello. I am a new P38 owner and received my truck with a bad damper. I went with the terrafirma and it’s good for me. I mention the above because I have nothing to compare it to other than a huge improvement. I am happy with my decision. Never know what the future holds for her...

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Alan Lindsay

Discussion Starter · #10 · Oct 15, 2018

Hi all,
Thanks for all the excellent replies
i believe I have identified the problem and I think it is good news!
it appears the problem lies not with the ABS relay but with the fuse box.
when I wriggle no. 17 ABS relay the pump will activate. When it activates it builds pressure in 20 seconds or so and then gives 3 brake activations before the warning lights reappear.
It is definitely the fuse box not the relay as I substituted a similar relay with no improvement.
i did all the usual thing like cleaning contacts and applying electrical spray but it is still intermittent.
i will remove the fuse box and investigate.
The fuse box has been problematic. For those interested I did an unusual repair to the fuse box blower relay two years ago that I recorded on this forum
regards
Al

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Richard_G

· #11 · Oct 15, 2018

Contact cleaner won't work as it isn't the contact between the box and relay but the internal connection between the contact and fusebox PCB. With heat the solder will crack so there is an intermittent connection, see https://www.rangerovers.net/repairdetails/electrical/fusebox.html. You can try another repair but in all honesty, your only real fix is a new fusebox. Make sure you use the correct dual pole relay to handle the current too.

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