ABS Problem

[DavidCr]

I have a 2011 Forester, 2.4 Auto. The ABS and traction control lights came on, scan showed right rear sensor was the problem. Replaced the sensor, it was clear where the cable was damaged, lights went off, problem solved. A week later sales lights came back on, this time rear left sensor was shown as the problem by the scan. Replaced the sensor, very clear where the cable had been damaged (in two places), but this time dashboard lights stayed on. Tested resistance on old sensor, about 815 ohms. Removed new sensor and tested resistance, resistance 835 ohms. Given the damage to the wheel speed sensor cable, I am surprised that the fault wasn't resolved. I have checked the abs fuse, no problem. Can someone tell me where to from here?

 

Thank you

[Mr B]

What brand replacement sensor ?
what scan tools, scope tools you got to help diagnose ?
you could temporarily repair cable on old sensor and refit to see if code clears which would indicate new sensor faulty/giving out of spec bias voltage .

Not uncommon have fault lights remain on with lot of the more low quality brand sensor parts, If we not fussy on brands we use we would have over 50% that still flag fault code or create operation faults due to out of spec signal data .
Never overlook new part issues especially on electrical sensors as most brands these days are garbage .

[DavidCr]

I bought a Blue Print part. The agents don't have any in stock and dont expect any until after Christmas. At over £200 for one sensor I thought I would look aftermarket. What brand do you recommend?

I have a Icarsoft pro scanner, which seems to do most things. My next step is to check the feed wire where the wheel speed sensor connects and see if there is voltage there. If there is, I will try a new sensor, different brand if I can get one.

Thanks for the reply

[Mr B]

blueprint use to be quite good but it now under the febi bilstein group and lot of parts tend be same EU sourced parts (garbage) as these brands rather than better Japan oem manufacturers it was before .
I would try likes of ICP and amayama for oem part . other brands for abs sensor would be Bosch or ABS .
Checking voltage to sensor would be good, your easiest test methods are either using old sensor with repaired harness or with some cable and t-pins make some extensions to connect left sensor to right and right to left and see if code swaps to right, if it does then it certainly sensor assembly related .
Without decent speed live data scanner and a basic scope diagnosis can be a more limited process .
You can get a pretty good scope platform for under £50 these days (HScope is amazing low entry tool for automotive diag work),

[DavidCr]

Thanks Mr. B. Will test the voltage to sensor connector first, if that's ok then I know the issue is downstream. If it's downstream I will 'swop' right and left using cables and see if the fault switches sides. I did try repairing the cables on the old sensor but the break was really close to the plug so quite difficult. The resistance in the new and repaired old parts was almost the same and plugging in the old part didn't clear the code, although I am not certain how good the connection was.

Will have a go tomorrow and let you know how I get on

Thanks

[Mr B]

If the code doesn't clear and come right back without vehicle moving it indeed likely wiring or new sensor creating a bias voltage that out of spec to the code criteria limits , but do realise it could still be issue with the signal return line at any point or even computer itself (uncommon but possible) . This where reading live data via scan tool or visual representation on the sensor output wiring with a scope becomes advantageous .
Not uncommon have issues with aftermarket sensors and as the Blueprint ones are close to 10th the price of oem you know they ain't high quality, Blueprint japan sourced likely been 60 to 100 but they would work well .
Biggest issue we have in trade these days is sourcing quality parts and getting customers understand we not fleecing them by using oem or higher priced specific brand aftermarket .
Lot of what was reputable aftermarket brands have turned to lower quality sourcing and lot of motor factors only stock garbage brands these days, ECP being one of the worst lol .
Fact customers can find parts (garbage with a fancy sticker or in a fancy box) on eBay or Amazon for price of a takeaway makes it even harder at times lol .