P38A ABS / TC lights, 'sticky' ?

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TallPaulB

Active Member
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146
Location
Manchester, UK
As subject, I had a fault in my ABS (the accumulator had gone). I've fixed the fault, and the brakes work fine now, but the lights are still on (all 3 on the dash, the ABS, exclamation and the TC light). Is this one of those faults I need to plug in a faultmate / nanocom in to read and clear, or do I still have a fault? It's a 2001 Model if that makes a difference.

I recently changed the shocks, and removed the front wheels to get at them properly so it's possible I've dinged one of the ABS sensors while doing that, but knowing whether there is still a fault before I start messing about with it would be handy.

And yes, I know I need to get a nanocom or a faultmate at some point, but £400 is a bit steep this side of christmas, so if I don't need to buy one right now, I'd rather wait.
 
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Year does make a difference as it means you have 4 wheel traction control and a Wabco D ecu, check the wheel sensors are push in properly, but you may need it plugged in to clear fault code.
 
The 3 amigos should light up on startup. After the ABS pump has done it stuff one of them should go off. Another should go off with the handbrake and then the final one will go out once you hit about 5 mph.

If the pump one isn't going out and you've changed the accumulator then bleed the system as per RAVE making sure the reservoir is regularly topped up. If air has got into it then it can be a sod getting it all out. If that stiull doesn't do it then there's the pump and pressure switch but neither is cheap.

ABS. The 4W TC seems to be more troublesome than the 2W TC or 0W TC ones. Check the ABS sensors are pushed all the way in and the wires are good. If it is the ABS ECU then @martyuk has managed to repair a few. The 4W TC ones cost a bl**dy fortune, of course.
 
All 3 are remaining lit for at least an hour (that's the furthest I've driven recently) at a variety of speeds. Could a dodgy sensor result in all 3 remaining lit or would it just be the ABS light?

For context, everything was working fine, then I changed the shocks. Everything remained fine for a couple of days after that, then the Accumulator went (tested by pumping the brakes 30 times and then switching the car on...pump ran for about 5 seconds) which resulted in all the lights staying on, and the brakes being 'interesting'. After replacing the accumulator the brakes now work fine, but the lights aren't going out.

I suspect I've just clobbered one of the sensors when I did the shocks but if that wouldn't cause all 3 lights to stay on....then something else is clearly at fault!

Edit: more context, I'm currently running without an EAS ECU with the EAS in 'manual' mode. Does the TC or ABS computer talk to / rely on the EAS ECU at all?
 
No, there is no relation between the EAS ECU and the ABS ECU - other than the fact the EAS ECU gets a road speed signal (though this is sent from the BECM anyway, after it receives the road speed from ABS ECU).

If you are getting the lights on all the time, and it's only started happening since changing the front shocks - then I'd say that it's a fair bet that one of those sensors has failed. Diagnostics is the easiest way to tell where the issue lies/what the system thinks is wrong.

The later 'D' Series ECU's do fail - but generally the stored fault code is "LH Rear Sensor Short To Another Sensor" and it is a component failure in the ECU itself. I'm still betting on it being a front sensor firstly. The later D series ECUs also self-check once powered up and if the fault is gone, then they will respond normally. Sometimes the first drive when the fault is rectified you will get a TRACTION FAILURE on the dash at startup - though all the lights will go out, and then a repeat of TRACTION FAILURE once switching off. However the second time you start it up and drive, you should get no faults on the dash or warning lights. That's my observation from the ECU's I've repaired anyway.
 
Brilliant, thanks Marty, exactly the information I was after. I'll have a look at the sensors this weekend and see if anything is obviously wrong / reseat them. MOT is due mid January (first one since owning the car) so if there's not an obviously broken sensor down there I might have to bite the bullet and shell out for a diagnostics unit.

Is the nanocom the recommended unit, the faultmate a (slightly) cheaper alternative and the Hawkeye not recommended at all unless you have more than one car / model to work on generally speaking?
 
TallPaulB said:
Brilliant, thanks Marty, exactly the information I was after. I'll have a look at the sensors this weekend and see if anything is obviously wrong / reseat them. MOT is due mid January (first one since owning the car) so if there's not an obviously broken sensor down there I might have to bite the bullet and shell out for a diagnostics unit.

Is the nanocom the recommended unit, the faultmate a (slightly) cheaper alternative and the Hawkeye not recommended at all unless you have more than one car / model to work on generally speaking?
Click to expand...

Nanocom is best for the cash. Faultmate is VIN locked unless serious money crosses Colin's palm. Hawkeye is OK but not as handy or capable as the Nanocom.

LZIR map may show someone near you who can help for a few beers. I don't know where in Manchester you are but there's a Nanocom unit or two in Cheshire. @Wazzajnr spings to mind. @tarphenry might have one up near Bury as well.
 
Nanocom, far best value for money. Faultmate, as mentioned are VIN locked - but you also need to hook it up to a PC with software to communicate to the vehicle. Nanocom it's all in one, and fits in the glove box/ cubby box so you have it with you all the time.
 
I've got nanocom for thor engined p38 and happy to put it on for you if you can get to Standish sometime.
If yours is gems, it should still read everything apart from engine.
Pack of choccy hobnobs is my charge for plugging it in and clearing any codes and you get a cuppa tea thrown in.
Pm me if you wanna bob down.
 
Three lamps, Hand brake/level lamp (Red). TC lamp. ABS lamp. Hand brake on = red lamp. Hand brake off, lamp should go out. If it stays on fluid level is low. TC lamp should come on with ignition and go out when minimum working pressure is reached. ABS lamp should flash on with ignition, then off, then come on and go out only when 5 mph is exceeded. If he has been playing pumping brake he may have switched TC off. That will cause lamp to come on and give a bleeping sound. It should go out and return to TC on at 5 mph. BUT if he has switched off TC and ABS is not receiving a speed signal. TC and ABS lamps will not go out. Speed signal to ABS ECU comes from O/S front sensor. As far as i can see.
 
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wammers said:
There is not much point in people asking for help, then when they get an answer they don't like insist they know more than you do. If you are an expert why ask in the first place.
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Seems to be a common problem. I often wonder what happened to the guy who was designing a new HEVAC for the P38, another simple job NOT.
 
Datatek said:
Seems to be a common problem. I often wonder what happened to the guy who was designing a new HEVAC for the P38, another simple job NOT.
Click to expand...

Yep, I have done this and that and now my car won't work. Put it back to standard then we'll talk, does not seem to be an acceptable opening statement. Cause they are experts and cannot have done anything wrong. Bloody ridiculous.
 
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