So after a couple of months using the p38 the fault is still occurring but only when I press the brake pedal and only when pressing the pedal when manoeuvring slowly. Last week I came to the conclusion the accumulator must be at fault and not holding pressure, I changed it yesterday went for a run pumped brake a lot when parking and no abs tc light. Started to drive out of garage today and it’s on again when touching brake pedal whilst manoeuvring, I was going to change abs ecu but didn’t because the problem only occurs when pressing brake pedal lightly. No faults showing on Nanocom, one thing I will say is when abs tc lights come on and traction failure comes up on dash when ign turned off both lights stay on on restart and go off together once speed up to about 5 mph but under normal working tc light goes out once system is up to pressure then abs light goes off at 5 mph like it should. Any more ideas?
Thanks Richard
Not sure I follow the fault. Until the system is up to pressure, you'll get all 3 lights on (ABS, Brake warning and TC), once up to pressure Brake warning and TC will go out (as long as you have the handbrake off otherwise the brake warning light will stay on until you release it), ABS will stay on until you hit 5mph forwards (it doesn't seem to go out in reverse, or mine doesn't anyway) then it will go out. Are you saying that you get the faults if you use the brakes while reversing but before it is up to pressure but when driving normally, you don't?
But if that is the case, you do still have a fault. I start mine, reverse off the driveway (so use the brakes then) and drive off down the road. If I don't leave it idling before I start moving, it comes up to pressure and the lights go out as I pass the bus shelter about 50m down the road. I do this every time I go anywhere and don't get any faults.
Thanks for reply, when I start up the vehicle I wait till tc light goes out before moving off and then abs goes off over5 mph. The abs tc lights do not come on under normal breaking only when light application of the brake pedal occurs. Once the abs tc lights come on and the ignition is turned off the traction failure notice comes on the dashboard. When I start the vehicle again the abs tc lights stay on and the tc light does not go out until the abs goes out at 5 mph and they both go out together.
So after more searching on the net, I came across an article on Landyzone about what to do if Nanocom kept showing no faults although a fault is still present, this consisted of scrolling left and right on screen and it revealed a fault. This showed front left sensor electrical failure intermittent 18 times. Then further on the article mentioned a fault with the brake light switch where with the Wabco D the Brake switches would either be both open or both closed when pressing the brake pedal. Well I tried pressing pedal whilst watching the screen and under light pedal pressure I was getting no 1 open and no 2 closed, with firm pressure on pedal the switch worked as it should. It is only under light pedal pressure I kept getting the abs fault, new switch ordered and I will address the electrical failure once I’ve hopefully sorted the first problem. Thanks Richard
So new brake light switch arrived and after fitting I checked on Nanocom as brake pedal was pressed and got the same indication of switches 1and 2 one open one closed, and the same situation when pressing brake pedal lightly abs and tc on again. I had taken the trim in footwell out to look at white connector for corrosion,as I put trim back in I caught brake pedal underneath with my arm which caused the plunger of the switch to push in, I had previously let brake pedal up slowly as per instructions. I checked movement of switch and it was still touching pedal so decided to do a road test, after initial traction failure warning whe ignition turned on and AB’s light clearing at 5 mph so far no abs tc warning when light pressure applied to brake pedal. Long may it last.
Good news!
I was hoping this thread might give me a clue to a problem that I was shown this evening by a guy at the other half's gym. She'd suggested he spoke to me so he did. This is on a 2001 Vogue and he has an ABS problem (Wabco D system) in as much as it always operates. Apparently it started after his mechanic had changed an ABS ring (no idea why it needed changing) and has done it ever since. His mechanic has changed sensors, bled the brakes multiple times and even changed the ECU. Whenever he applies the brakes you can hear the ABS operating and feel it though the brake pedal, unless he presses harder when it as if he goes through some sort of resistance and the brakes work normally, just slamming on far too hard (as you would expect when stomping on the pedal). I put the Nano on it and no faults shown, voltage from the sensors all the same and all showing 1.7kph when standing still but increasing at what appeared to be the same rate, none were staying low or lagging behind the others anyway. No ABS Failure warning on the dash or 3 amigos to suggest anything is wrong.
It's going back to the mechanic again next week but if he can't find the problem, and as he has failed so far I can't see this time being any different, it'll be coming to me. Just wondering if anyone has any clues.
I don't know if this is it, but my recent issue with ABS which was similar, except that it would only activate ABS when slowing down to turn a sharp right out of a car park. No errors flagged, and all ABS and TC lights on.
Turned out, I had a very bad wheel bearing, and the reluctor was kicking the sensor back every time I re seated it.
New hub, with, as you will recall, a hole which kept the sensor from seating fully...... Drilled hole out to allow sensor in the last 3mm, and problem solved.
Possibly, the new reluctor is slightly eccentric, causing the sensor to push back out as soon as you make 1 revolution of the wheel?? Is the sensor actually going through the hole in the hub dust shield?
Is the wheel bearing good? Mine was very bad, yet there was no real evidence of this via noise or handling other than
a slight wobbly feel, but just occasionally......
Can you get any travel on the sensor once it has been driven?
Nano showed 1.7kph at rest, and it looked like the speeds were all increasing as I accelerated, until it stopped sending data at about 5kph. Getting it to re connect at 30kph showed the sensor error on rt front.
The whole time this was going on, and the ABS and TC lights were on, there was never any faults shown on Nano.....
Good luck!
So now I've got the car here and it gets curiouser. Checked the brake light switches with the Nano and sw1 was operating before sw2 so I thought that was it. However, after pinching the brake light switch off the Ascot, fitting that and checking with the Nano and seeing both operating at the same time, a quick blast up the road revealed it was no different. At speeds up to about 25mph the brakes are fine, at anything over that, the ABS can be heard and felt through the brake pedal. ABS modulator looks to be new so bled that, but only that, and while a tiny bit of air came out, again no different. Tomorrow it's going to be a wheels off and check all the sensors and reluctor rings.
No matter how hard I tried I could not get the Nano to connect when moving so other than being able to see the individual wheel speeds at up to around 6kph, I wasn't able to check them at any higher speeds. One thing that I am confused about, not usually working on Wabco D systems, is the Inlet and Outlet valve voltages. All of them show 0.00V except at odd times one or two will jump to 0.06V. However, the Nano documentation says that this shows the voltages to the individual valves and I would have thought that with the brake pedal pressed a voltage would appear but it doesn't, they all stay at 0.00V (with the odd change to 0.06V).
A bit more information on this problem which has had me and a recently retired Land Rover mechanic scratching our heads. I'd only been given parts of the story but have now got a full sequence of events. The ABS light was staying on and he was getting ABS and Traction faults. That was down to the ABS ring on the LH rear which was changed and the problem has been there ever since. Although his mechanic had told him he had changed sensors, they hadn't been changed but it does have a brand new accumulator and brake modulator. The shield on both front hubs has been slotted so the hub can be taken out without removing the sensor which also means you can see the ring and the end of the sensor and check the air gap. We gave both front sensors a tap with the mallet to make sure they were fully home before turning out attention to the rear.
LH rear sensor came out without too much effort and looking down the hole the ring had a lot of oil on it. Now whether this was done by whoever change the ring or the axle oil seal is leaking, I don't know but we pulled the hub out slightly to allow it to drain and cleaned it up with a liberal spray of brake cleaner. Put that back together and tried it again. Up to 25mph the brakes are perfect but over that the ABS is kicking in. Theory was that while the speed readings were fine up to 5mph when the Nano disconnected, maybe once over 25mph one sensor was reporting an incorrect speed so the ABS was kicking in then. OK, so we've done 3 out of 4, lets attack the RH rear. On this, despite them normally putting up a monumental fight, I got hold of the sensor and just pulled it out. No pliers, no wiggling, it just pulled straight out. the ring looked pretty horrible and rusted so it was cleaned up with a combination of scraping the crap out from between the teeth with a screwdriver, blasting it with brake cleaner to degrease it and finishing off with an airline. Put the sensor back in but before putting the wheel back on, tried turning the hub while I had my finger on the sensor. For 2/3rds of a turn it could feel every tooth as it went past the sensor but for the other 1/3rd of a turn, I couldn't. So it looks like that one is a bit worn or is slightly off centre (or the wheel bearing is on its way out). Took it out to see if it was any different.
Up to 25mph the brakes are fine, at around 30mph the ABS is coming on but it still stops OK but it gets really scary at 50 mph. Hit the brake pedal, the ABS can be felt working but the brakes aren't! It is only when you really stamp on the pedal that they work, but then you are into scraping your passenger off the inside of the windscreen type braking. It is almost as if, rather than releasing one wheel that it thinks is turning slower than the others, it is releasing all of them and maybe only braking on one wheel. But if it was doing that, it would pull to one side so I think releasing, or not applying, all 4 is closer to what is happening. Maybe the lack of voltage being shown on the valves is correct, rather than the Nano just not showing them, and it is an electronic problem?
I'm going to see if I can get a halfshaft with a non corroded ring and try to swap the ABS ECU for a known good one because by now, with a combined 50+ years of working on Land Rovers, it's got both of us baffled. If only we could get the Nano to connect at above 30mph we'd at least know what wheel speeds are being reported.
dumb question , but have you lifted just one sensor and see if you get ABS fault on the dash , this disables abs and traction control so it should just have standard brakes . if you still have troubles lift them all and eliminate the sensors . so if it's something else you can look elsewhere.
I haven't but I did think after the owner had taken it away I could have pulled the ABS fuse so it doesn't do anything. At least he'll have brakes, just no ABS or TC (and a dash full of warning lights).
I'm still a little confused by some of the readings I get on the Nanocom though. Both my cars have the earlier Wabco C system and this is Wabco D. When looking at the two brake light switch status, on the C system one is open and one is closed and they swap over when the brake pedal is pressed. On the D system they both show the same status and change from open to closed (or the other way round) when the brake pedal is pressed. That would suggest that the switches are different but the parts list shows the original part number for a C system car supersedes to the same one as fitted to a D system car which makes me think they must be interchangeable? The inlet and outlet valve voltages not changing when the brake pedal is pressed doesn't seem right either but I need to find a D system equipped car with working brakes to stick the Nano on and see what that reads.
to pull the fuse takes the power out of the system , lifting the sensor only disables the system , everything still has power so if it's still a problem it should be easier to find as it's not supposed to work, maybe.
the alarm should read ABS Fault on the dash ,nothing else.
Hi Richard, middle of the next week I´ll have a friends Motronic P38 here and I can check with my Nano the readings (and can compare to my own Gems).
What exactly should I look for if that is any help for You?
The car is coming back to me on Monday so it might be too late. However, the readings I want to know is whether the two brake light switches should both be the same (both open and then both closed when the brake pedal is pressed) or if they should swap over so one open and one closed as on my GEMS. There are also screens showing Inlet and outlet valve voltages. These are all at 0.00V (with the occasional 0.06V showing intermittently) but do not change when the brake pedal is pressed. I would have expected them to but they don't.
It's a bit of a pain that the ECU disconnects diagnostics once over about 5mph, being able to see what it is doing at speed would be very useful.
Do you have something like a Hantek multi-channel USB scope available ? If so hook up the 4 sensors & see how the signals look at speed.
No afraid I don't, all I've got is a graphical multimeter which would be able to show one sensor but with a lot of messing around swapping from one to another. Not only that, if the sensors were reporting differing speeds, I would expect it to bring up an ABS fault on the dash and log a fault too.
A scope is one of those things that I wish I had once or twice a year but I was spoilt when working with having £40k+ worth of high quality test equipment as personal issue so the affordable stuff always seems inferior to what I got used to using.
Latest update is that I suggested to the owner that he pulled Fuse 38 and tried it. Despite having the ABS and TC lights on permanently, the brakes are working perfectly....
However, the readings I want to know is whether the two brake light switches should both be the same (both open and then both closed when the brake pedal is pressed) or if they should swap over so one open and one closed as on my GEMS.
Overcome with joy as I finally have a faultless ABS-TC system, I confirm that both switches change position at the same time on my '99, I have checked with the Nano a while earlier.
In my case only one was "switching" (number 2 with the CC vacuum pipe), the problem was a faulty connection in the damn C0229 by the RH footwell, pin 14 with a Green/Purple wire, that sends a signal to the ABS ECU when the pedal is depressed. Finally fixed!! Finally the thing is working and no bothering beep beeps.
I suggest to all to check that connection, and also pin 9 Yellow/Purple cable on the same connector, again from brake switch to ABS and ECM ECUs (probably this is the TC signal).