Brake Fault - Help

bearhouse · 13th May 2024, 16:53

Hi All,

My 2.5V6 now has a permanent brake fault. That is brake fault warning comes up in the message centre on ignition and the red / brake / handbrake light remains on. What might cause this?

I’m told it might be the hand brake switch but I’m assuming I wouldn’t get the brake fault warning if it was the switch?

The second suggestion is it might be brake fluid level. But that’s at maximum and the garage said I would get brake fluid low if it was the level switch.

Any suggestions as to anything else I can check?

Regards,

Terry

xsport · 13th May 2024, 18:01

Have you checked you have got both stop lights working at the rear . Does the handbrake light warning light go off when the handbrake is released. Could be a double fault at the same time ..together .. check these out first...

SD1too · 13th May 2024, 18:57

Quote:

Originally Posted by bearhouse

... brake fault warning comes up in the message centre ... and the red / brake / handbrake light remains on. What might cause this?

If that's the only warning in the message centre Terry, RAVE says it's either that the handbrake is on or the brake fluid level is low.

Quote:

Originally Posted by bearhouse

I’m told it might be the hand brake switch but I’m assuming I wouldn’t get the brake fault warning if it was the switch?

You would get the brake fault warning Terry, yes. Why have you assumed that you wouldn't?

Quote:

Originally Posted by bearhouse

The second suggestion is it might be brake fluid level. But that’s at maximum and the garage said I would get brake fluid low if it was the level switch.

According to RAVE low fluid level would illuminate the "brake fault" warning lamp. There isn't a separate "brake fluid low" warning.

I hope that this is of some assistance.

Simon

bearhouse · 14th May 2024, 11:24

Yes, all brake lights working. No, the brake warning light is on all the time, even with the handbrake released.

When I start the ignition, I get an ABS fault waring, traction control off warning and Brake Fault Warning with the brake light staying on.

I've managed to test the handbrake switch which is ok.

I can't see how to get to the brake reservoir switch, any suggestions as to how to test? Can it be tested on TOAF?

I had the ABS pump replaced yesterday to hopefully cure something but no change. We now think the ABS connector is so corroded that it's causing a problem and not connecting all pins to the pump. I'm trying to find a replacement connector that I can splice in but my car is a 2.5 V6 with traction so I need from that model. Does anyone have one available for sale?

xsport · 14th May 2024, 16:10

If the connections/pins are not connecting properly .. then why is the abs light going out ? Why does this not stay on ? . also ,just wondering .. is the traction plug under the throttle body connected ok ? What does T4 say ...

bearhouse · 20th May 2024, 06:13

The ABS light is not going out. Yes, the plug on to the traction control unit is in place. I still think it's the connections to the ABS pump. TOAF says there's a relay fault on the pump.

Arctic · 20th May 2024, 09:39

Quote:

Originally Posted by bearhouse

Yes, all brake lights working. No, the brake warning light is on all the time, even with the handbrake released.

When I start the ignition, I get an ABS fault waring, traction control off warning and Brake Fault Warning with the brake light staying on.

Quote:

I've managed to test the handbrake switch which is ok.

I can't see how to get to the brake reservoir switch, any suggestions as to how to test? Can it be tested on TOAF?

I had the ABS pump replaced yesterday to hopefully cure something but no change. We now think the ABS connector is so corroded that it's causing a problem and not connecting all pins to the pump. I'm trying to find a replacement connector that I can splice in but my car is a 2.5 V6 with traction so I need from that model. Does anyone have one available for sale?

How did you test the handbrake switch?

xsport · 20th May 2024, 19:51

Good point arctic. Its a hall switch is it not ... on the brake cylinder ... how to check .. ? I suppose for continuity on the handbrake switch .

Arctic · 20th May 2024, 23:08

Quote:

Originally Posted by xsport

Good point arctic. Its a hall switch is it not ... on the brake cylinder ... how to check .. ? I suppose for continuity on the handbrake switch .

Hi Stefan.
It's just a normal on off switch hopefully the photo below shows the switch attached to the handbrake lever mechanism.

1

2

One wire going to the switch.

bearhouse · 21st May 2024, 05:09

Hi Stefan & Arctic,

The brake fluid switch is a hall effect / reed switch. This means it works by a magnet. I removed the switch from the car. Put a multimeter on continuity across both contacts. Normally, the switch is open until you bring a magnet near the switch. The outputs then short. As it was such a pain to remove the switch, before I put it back, I put a shorting link into the connector plug to see if the fault clears which it didn't so I'm reasonably sure my switch is ok.

With regards to the handbrake switch. I'm confused as to how this can cause a 'Brake Fault' to come up in the message display. I appreciate a faulty switch can cause the handbrake / brake warning light to stay on if the switch stays shorted, even with the handbrake off. If I'm wrong, please explain.

Looking at the handbrake switch without removing it, it looks like it only has one connection to it. I assumed the other side is taken down to -ve or the chassis. So, unplugging the connector, with a meter on continuity. One end on the switch contact and the other end on the metal of the handbrake and with the handbrake up you get a short and with it released it's open.

If I've got either test wrong, please advise.

Otherwise, brake signals go to the ABS pump. As my ABS pump connector plug is corroded, I'm assuming my fault lies there?

13th May 2024, 16:53	#1
bearhouse Avid contributor Rover 75 Join Date: Aug 2009 Location: Herts Posts: 114 Thanks: 0 Thanked 0 Times in 0 Posts	Brake Fault - Help Hi All, My 2.5V6 now has a permanent brake fault. That is brake fault warning comes up in the message centre on ignition and the red / brake / handbrake light remains on. What might cause this? I’m told it might be the hand brake switch but I’m assuming I wouldn’t get the brake fault warning if it was the switch? The second suggestion is it might be brake fluid level. But that’s at maximum and the garage said I would get brake fluid low if it was the level switch. Any suggestions as to anything else I can check? Regards, Terry

14th May 2024, 11:24	#4
bearhouse Avid contributor Rover 75 Join Date: Aug 2009 Location: Herts Posts: 114 Thanks: 0 Thanked 0 Times in 0 Posts	Yes, all brake lights working. No, the brake warning light is on all the time, even with the handbrake released. When I start the ignition, I get an ABS fault waring, traction control off warning and Brake Fault Warning with the brake light staying on. I've managed to test the handbrake switch which is ok. I can't see how to get to the brake reservoir switch, any suggestions as to how to test? Can it be tested on TOAF? I had the ABS pump replaced yesterday to hopefully cure something but no change. We now think the ABS connector is so corroded that it's causing a problem and not connecting all pins to the pump. I'm trying to find a replacement connector that I can splice in but my car is a 2.5 V6 with traction so I need from that model. Does anyone have one available for sale? Last edited by bearhouse; 14th May 2024 at 12:15..

20th May 2024, 19:51	#8
xsport Posted a thing or two rover 75 club se Join Date: Apr 2011 Location: Leicester Posts: 1,741 Thanks: 358 Thanked 419 Times in 310 Posts	Good point arctic. Its a hall switch is it not ... on the brake cylinder ... how to check .. ? I suppose for continuity on the handbrake switch . Last edited by xsport; 20th May 2024 at 19:54..

13th May 2024, 18:01	#2
xsport Posted a thing or two rover 75 club se Join Date: Apr 2011 Location: Leicester Posts: 1,741 Thanks: 358 Thanked 419 Times in 310 Posts	Have you checked you have got both stop lights working at the rear . Does the handbrake light warning light go off when the handbrake is released. Could be a double fault at the same time ..together .. check these out first...

14th May 2024, 16:10	#5
xsport Posted a thing or two rover 75 club se Join Date: Apr 2011 Location: Leicester Posts: 1,741 Thanks: 358 Thanked 419 Times in 310 Posts	If the connections/pins are not connecting properly .. then why is the abs light going out ? Why does this not stay on ? . also ,just wondering .. is the traction plug under the throttle body connected ok ? What does T4 say ...

20th May 2024, 06:13	#6
bearhouse Avid contributor Rover 75 Join Date: Aug 2009 Location: Herts Posts: 114 Thanks: 0 Thanked 0 Times in 0 Posts	The ABS light is not going out. Yes, the plug on to the traction control unit is in place. I still think it's the connections to the ABS pump. TOAF says there's a relay fault on the pump.

21st May 2024, 05:09	#10
bearhouse Avid contributor Rover 75 Join Date: Aug 2009 Location: Herts Posts: 114 Thanks: 0 Thanked 0 Times in 0 Posts	Hi Stefan & Arctic, The brake fluid switch is a hall effect / reed switch. This means it works by a magnet. I removed the switch from the car. Put a multimeter on continuity across both contacts. Normally, the switch is open until you bring a magnet near the switch. The outputs then short. As it was such a pain to remove the switch, before I put it back, I put a shorting link into the connector plug to see if the fault clears which it didn't so I'm reasonably sure my switch is ok. With regards to the handbrake switch. I'm confused as to how this can cause a 'Brake Fault' to come up in the message display. I appreciate a faulty switch can cause the handbrake / brake warning light to stay on if the switch stays shorted, even with the handbrake off. If I'm wrong, please explain. Looking at the handbrake switch without removing it, it looks like it only has one connection to it. I assumed the other side is taken down to -ve or the chassis. So, unplugging the connector, with a meter on continuity. One end on the switch contact and the other end on the metal of the handbrake and with the handbrake up you get a short and with it released it's open. If I've got either test wrong, please advise. Otherwise, brake signals go to the ABS pump. As my ABS pump connector plug is corroded, I'm assuming my fault lies there?