Yaris Mk2 ABS annoyance

[Jim_Bergerac]

Hi all.  I recently bought a 2007 Yaris D-4D 

It's absolutely perfect in every way... apart from the ABS light staying on 

It was scanned at a Toyota dealer and showed the following codes-

C1251 - pump motor locked/ open

C0215 - rear left wheel sensor.

The dealership quoted more than the car is worth to replace everything so I've had no choice but to wade in myself.

After checking all fuses and wiring/ earth points, I fitted a new, non-genuine sensor on the NSR corner.  I reset the codes and went for a ride.  Light was initially behaving as it should but soon came on again.  As before, I got both same codes again. 

 After reading about the ATE ABS pump with its integral ECU being a bit 'flakey', I then replaced the whole unit with a very low mileage unit.  After reconnecting the Battery and starting up, the light went out on its own, as it should and everything seemed fine... but then came on again while road testing.  This time, the C1251 code wasn't present, only C0215 (wheel sensor).

I'm pretty sure I've sorted the pump problem now and everything seems fine but the NS/R sensor code persists.  The ABS light is still on all the time.

Anyone have any advice as to where I should go now?  I'm thinking another replacement of the lefthand rear sensor will have to be done, but I'm not sure why.  Any 'gothchas' with this kind of fault?

Many thanks :)

[Devon Aygo]

There is a technical service bulletin ( CP-0039T-0908-EN ) that includes C0215 as a possible issue, the fault was water ingress into the rear sensor harnesses, the fault was fixed in production by March 2008 so your 2007 could be affected the fix was new sensors and rear harnesses.

As you have replaced the sensor already then you may just need the harnesses:

RH harness - 89516-0D070

LH harness - 89516-0D080

[Jim_Bergerac]

Thankyou for replying; I had heard of a water ingress problem (mainly from US owners) but discounted it because there was no corrosion visible in either the sensor plug or the wire pins.  In fact, everything was/ is dry and shiny as you'd expect.  The plug pins on the wire are absolutely tiny though, so I can't see a lot.

I think it's worth a shot though, I'm running out of ideas!  Thanks for the part nos- very useful 

[Donsky]

A friend of mine had the same problem, after 5 visits to the dealer it turned out to be a short in the wiring.

[Jim_Bergerac]

That doesn't sound good Donsky!  I have thought it may be a wiring fault but really don't want to rip the interior out of the car..

I think I will try the sensor wire (that, I think disappears under the rear seat?) like Devon says, and go from there.

 

I wonder if it's worth swapping over both rear hubs with each other, resetting the codes and seeing if the same side flags up the fault again?

Only flaw in that plan is having to disturb the RH side...  the LH was all rusted together and a pig to remove from the brake backplate!!  

[Jim_Bergerac]

Just to add a little closure to this (and for the sake of any poor soul suffering similar ABS problems....) there were two faults on this car-

The ABS pump/ECU which was giving spurious fault codes and was replaced.  It's a common failure and luckily if you match the unit numbers up, you can fit a 2nd hand ECU/ pump assembly with no problems at all- it is not coded to the car.  Not ideal, but a new part was costing more than the car is worth.  The unit is a ATE one and there are companies now that will repair the fault on your ECU with a modification to stop it failing again.  I believe the mechanical side of the ABS unit is relatively reliable.

The other fault was with a rear sensor.  I thought I had this licked but the (non-genuine) replacement part was faulty.  This led me down the path of investigating wiring etc.  All this was ok, it was simply a case of the replacement part not being made correctly/ faulty from day one.  Very frustrating but it's sorted now and so nice to drive the car without the ABS light being on all the time!

[stantheman1]

Thanks for the update. :)

[dogdays]

The fault usually lies in the rear brake sensor. On the later models (Yaris 2) the sensor is incorporated within the wheel stub axle bearing / flange assembly and is impossible to change. I think on the earlier Yaris cars that the sensor can be changed though the plug is slightly different. Toyota want wellover £ 200 for the axle bearing sensor/unit, though you can get an aftermarket one for £37 on eBay.

Securely jack up the car and also support the vehicle on blocks. Take off the rear brake drum. Access is given to the four threaded bolts that hold the stub axle onto the cars radius arm  via holes in the wheel mounting flange. Undo the 6mm nut that holds the ABS cable onto the radius arm so as to give some slack. Undo the four  bolts( using 14mm thin socket)  and pull the stub axle forward clear of the radius arm whilst supporting it, so as not to damage the ABS cable. This will allow you to easily remove the ABS cable outer plastic cover, which hinges off. You will then be able, with a small screwdriver  to release the clip under the ABS sensors plug and remove the plug. Clean the plug with switch cleaner and then reassemble the sensor plug and external clip onto the new stub axle. Smear the plug with silicone grease to keep out water. Reverse the removal procedure smearing the location of the stub axle with ordinary grease where it plugs into the radius arm. When you have done this once, the entire job takes about  one hour