ABS Light Question

[Kafka]

I've searched the forum but was unable to find the answer to this, apologies if I'm covering old ground.

My AT200 Celica 1.8 ST (1997) has the ABS light on. Using the diagnostic jumper from E1 to TC in the diagnostic port, I was originally given codes 11, 31 and 32. I reasoned that if the relay was iffy then the 'downstream' codes of 31 and 32 which relate to the wheel sensors may be false positives so bought a replacement relay and swapped the old one out for the new one.

This worked surprisingly well, as codes 11 and 31 went away, indicating that there was a problem with the relay and that the right-hand wheel sensor was OK (code 31 went away). However, this does leave code 32 present, indicating a "Problem in left front wheel speed sensor circuit" based on this thread

My first question is are we talking about the 'Left' as you look at the car from in front of the bonnet, or from the drivers seat? So do we mean (UK) drivers side wheel, or passenger side wheel? I think it means passenger side, as it is the left hand wheel when sat in the drivers seat looking out the windscreen.

The second question is can anyone provide the Toyota part number for the ABS sensor in that wheel? As I understand it there is a sensor, and an ABS ring in the hub, am I likely to need to replace just one or both parts? Is anyone able to provide the part number(s) for them so I can purchase replacement(s) and hopefully clear the issue and get the light to go out! i have read the second section relating to the 'Special WSS Test Mode' but I'm having difficulty getting my head around it.

I plan to remove and clean up the sensor with contact cleaner and a toothbrush, and clean the ABS ring with a wire brush to begin with, but am banking on needing to replace one or both parts.

Thanks in advance

 

[Konrad C]

I can't give you the answers you are after but look at the following and use it for your info - http://www.japan-parts.eu/toyota/eu/1997/celica/at200l-blmska/4_252470_003_/electrical/8414_abs-vsc

Also go to toyodiy.com and sign up to get the diagrams as well as part numbers.

42450-20051

[Kafka]

Thanks you (again) Konrad! Part number has been found and now trying to track down a reasonably priced replacement sensor.

[Simon_P]

Hi My Friend 🙂

8 hours ago, Kafka said:

My first question is are we talking about the 'Left' as you look at the car from in front of the bonnet, or from the drivers seat? So do we mean (UK) drivers side wheel, or passenger side wheel? I think it means passenger side, as it is the left hand wheel when sat in the drivers seat looking out the windscreen.

Left is from the drivers seat so if is a standard RHD car then it is the passenger side.

8 hours ago, Kafka said:

The second question is can anyone provide the Toyota part number for the ABS sensor in that wheel? As I understand it there is a sensor, and an ABS ring in the hub, am I likely to need to replace just one or both parts? Is anyone able to provide the part number(s) for them so I can purchase replacement(s) and hopefully clear the issue and get the light to go out! i have read the second section relating to the 'Special WSS Test Mode' but I'm having difficulty getting my head around it.

Great site for toyota part numbers. Put in your vin and it gives you a comprehensive parts list.
http://www.toyodiy.com/parts/

Edited June 30, 2018 by Simon_P
hyperlink

[Konrad C]

10 hours ago, Simon_P said:

Hi My Friend 🙂

Left is from the drivers seat so if is a standard RHD car then it is the passenger side.

Great site for toyota part numbers. Put in your vin and it gives you a comprehensive parts list.
http://www.toyodiy.com/parts/

You need to make an account to see the images as well as part numbers. I use this sight along with http://www.japan-parts.eu/toyota 

Toyota are very consistent with each generation of cars, so fixes for the Celica, are the same for Avensis using the same engine. Also the OBD jumper wire/paper clip tricks are the same across most the cars for ABS, SRS and EML until OBD2 standard and VSC systems came along. Then you need a diagnostic scanner that supports these later functions.

[Kafka]

I dismantled the ABS sensor in the hub earlier, the magnetic end was gummed up with flakes of what I think is rust. I cleaned up the sensor end, and sanded down the rust flakes from the hole that the sensor mounts to.

The ABS ring looked to be in good condition when I looked through the hole in the hub and rotated the brake disc, clean metal with no visible cracks.

However on reassembly the ABS light remains on, and with the diagnostic paperclip suggests there is still an issue with the front left sensor (code 3-2).

Is there anything else I can do to try and fix this one, or is the most likely cause that the sensor is broken and I need a new one? There was no visible damage to the wiring for the sensor as it went up the front strut and into the loom in the inner wing.

 

[Kafka]

minor addition:

I've been out again to check the wiring at the top of the ABS sensor loom where it connects to the 'main' section of the loom that goes to the ABS ECU. I unplugged it, sprayed with contact cleaner and reconnected but to no avail.

There is a LHS sensor on eBay currently that I'm tempted by, however (now I've reassembled it all) an idea occurred to me. Where the sensor wiring connects to the main ABS loom there are 2 wires. Would it be massively naive to test for continuity here? I'm trying to work out if the issue is in the wire from hub to main loom (the ABS sensor bit) which is relatively easy to replace, at a cost; or is the issue upstream of this - i.e. in the main loom that goes from wheel sensor to ABS ECU which will be a total pain to fix.

So if I put a multimeter into continuity mode and connect it to the two wires on the sensor wiring side and it shows continuity then the sensor is OK. If its not showing continuity then the problem is in the sensor wiring despite no breaks being visible? likewise on the loom to the ECU, I need to test for continuity to see if the wiring from sensor connection to ECU is intact?

[Kafka]

For anyone faced with a similar issue, I thought I'd write up how I fixed this. New front ABS sensors are available from Toyota but are still quite pricey - £200 or so in the UK. Secondhand parts are one option, but parts for the AT200 are quite rare it seems, and you play the longevity game with any secondhand part thats now knocking on 20 years old.

The option I went for was to source a brand new Intercambio Cambiare VE701925 aftermarket ABS sensor for a 1994 - 1998 Toyota Camry. This cost me £30 including postage.

I jacked the Celica up, removed the front wheel, put and axle stand in and wedged the removed wheel under the sill in case the worst happened. Then turned the steering wheel to full right lock, making getting at the ABS sensor, which lives on the rear of the hub easier. The sensor is held into the hole in the hub with a single 10mm bolt.

You can see the sensor unbolted and moved aside here. Next up was to compare the old and new sensor ends side bty side. You can see that the new sensor is identical, but for the fact that the wires exit the sensor pointing 'down' not 'up'. This isn't an issue as we'll see later.

 

Next, we need to compare the othe end of the wiring - the bit that connects at the top of the wheelarch under the wheelarch liner to the loom that runs to the ABS ECU. Removing the wheelarch liner is fiddly, you need to undo multiple 10mm bolts and at least three philips head screws to bend it away enough to get access to the sensor wiring at the top. I chose to just bend the liner out of the way, but to do it properly undo all the bolts and screws and completely remove the liner. You don't have to though.

The original sensor wiring goes across the outside of the hub, where the damper connects, then goes into a metal bracket/guide thats held to the inner wing with 2 more 10mm bolts. Undo them, and the guide comes away. The connector at the top is a push-in affair with 2 spade connectors

 

The Camry connector is different - instead of a female connection with male spade connectors, its the inverse - a male connector with female spade terminals

This won't connect to the ECU loom at the top of the wheelarch, so here is where it gets interesting. I decided I had nothing to lose, and as both sensors had 2 wires - one white and one black - I would see if I could cut and solder the old sensor connector to the new sensor wiring. Here is what the top of the old sensor wiring looks like, you can also see the metal guide it sits in

I went to the shed, and carefully cut the wiring so i had about 2" of wire to play with after the connector

I then carefully cut away the black rubber coating that wraps the white and black wiring and holds it in place, and use some wire strippers to expose the bare copper ends of wire so I had something to solder. I then did the same with the new sensor, cutting the incorrect connector off the end, stripping the ends of the white and black wires and then slid a 2" section of heat shrink onto the wires out of the way. Then carefully soldered the white to the white wire. I'm not awfully good at soldering so its not especially neat, but was definitely joined

Next, I soldered the black wire, then carefully slid the heat shrink over the exposed soldered joint, and used a butane lighter to warm up the heat shrink so it it, ummm, shrunk.

Its not especially neat, but had sealed the solder and metal ends so they'd not get damaged or short when splashed with water on a wet day out in the car (I hoped).

The next thing to do was to carefully cut the old cable ties that held the rest of the old sensor into the metal bracket/guide, pull the old wiring out and then use new cable ties to route the new sensor wiring in. The guide is important as it stops the wiring from tangling in moving parts and from chafing. With this done, I trial fitted the bracket into the inner wing and had a look at the cable to make sure it had enough slack to allow it to move with the steering

There is enough slack to allow movement, but the routing isn't ideal. I needed to make sure that the wiring at the sensor end wasn't going to snag in the CV boot/gaiter really on full left lock. Before I did this though, I needed to test to see if the ABS light had gone out. I connected up the connector at the top of the inner arch after giving it come contact cleaner for good measure, put the car into diagnostic mode by pulling the jumper pin from the diagnostic socket, bridging E1 and TC with a paperclip and turning on the ignition. After tapping the brake pedal rapidly for 3 seconds, the ABS light settled into a on-off-on-off flash which indicated it was working correctly on all 4 sensors. What a relief!

I then went back and did up all the bolts holding the bracket.guide into place, refitted the wheelarch liner, and tightened up the bolt that holds the sensor into the hub after cleaning the hole it fit in up with a rough file. Next up was working out how to keep the end of the sensor wiring out of the CV boot gaiter. I reused the c-shaped plastic clip that routes the cable around the bottom of the damper, over the top of the hub, then using three cable ties around the track rod end I was able to make a loop that was loose enough to allow the cable to move with the steering (this is very important) but held tight enough to the TRE to keep it from snagging in any moving parts. I had to trim a 2" section of outer sheathing from the cable where it went through the plastic clip, the cable has a triple layer of rubberised sheath on it, and was slightly too fat to allow the clip to snap closed around it. With the outermost layer removed it fitted fine though.

 

With this done, I refitted the wheel, took the car back down off the jack and axle stand and took it for a run. The ABS light now comes on with the ignition, stays on for ~2 seconds then goes out - as it should. The light remains off the whole time after this. I took the car up to 70mph today and it is fine, it brakes fine with no ABS cutting in too early. I've not tried provoking it by slamming the brakes on to try and lock the wheels up yet, but will do when i can find a gravelly carpark as this is the easiest and safest way to test the ABS I've found.

 

Hopefully this may be useful to someone else. Mods, if this should be moved to the 'How To' section please do so, and apologies if its posted incorrectly.

 

[FROSTYBALLS]

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