Yes - ANOTHER ABS light question

[Bushwack]

Last week after the car sitting for about three weeks, I cranked it up and the ABS light stayed on. I let the car warm up to temperature, turned off the car, restarted and the light stayed on (only the ABS light). As I am not mechanically inclined, I bought an accumulator from Amazon (the car had the original installed), had it installed and the light still stays on. My mechanic then checked the main relay and the light still stays on. What's next?

If it helps, I did notice that in the past, the ABS light would stay on for 2-3 seconds after the red brake light would go off. A behavior that was odd compared to my previous Reatta when both lights would turn off simultaneously 5-7 seconds after start-up.

[padgett]

Do you get the "thump" ?

[Bushwack]

Not sure what you mean by 'thump'. When driving the car, brake pedal pressure feels the same.

[padgett]

Please take the brake test. (need to scroll down a bit)

[Bushwack]

I was reading 'thump' as pump and not as..thump. I took the test before changing the accumulator. I'll do it again and post my findings tomorrow/next day.

[padgett]

Only test 7 is relevant to the yellow light.

[Bushwack]

I went ahead and performed Test 7 (three times with the same results). Each time I get the thump within one second of turning the key to the run position. The intensity of the thump/feedback changed depending on how much pressure I first started applying to the brake pedal.

I'm not sure what the next step is. Mechanic ruled out the pump, doesn't think it's a relay (or he said the accumulator wouldn't work) and thinks it may be a bad wheel sensor.

Is there something else to consider?? Thanks.

[Ronnie]

"or he said the accumulator wouldn't work) and thinks it may be a bad wheel sensor." I think he is on the right track.

[padgett]

Thump means the EBCM is going through POST so is not the relay. BTW there are two - one for the pump and a second for the EBCM.

Have lost track of all the ABS threads but posted in one this morning the connector a circuit diagram for the EBCM (in trunk) connector. That shows how to measure the sensors with a DVM.

See my last post here.

Are you getting a 33 code ? I recall that being a right front and not a rear (prolly somewhere in the archives).

Good news is that it is on all of the time so problem is always there - is much easier to troubleshoot than an internittant.

Edited June 30, 2010 by padgett (see edit history)

[Bushwack]

An update... After changing the accumulator, the ABS light no longer stays on upon start-up. But, after testing various scenarios, the ABS light only comes on once I put the car in drive and move a few feet. Am I correct in assuming it's a wheel sensor and if so, are they available for purchase?

[padgett]

Probably, what code is setting ? Would use the same process as posted earlier to measure the resistances at the EBCM connector.

[Bushwack]

I'm not that mechanically inclined (re: measuring resistance). I'll let the mechanic do that. Are wheel sensors available from a retailer?

[Ronnie]

I believe these numbers are for the rear sensors:

NAPA: Part number: UP 530079. Price: $ 97.49 as of 5/28/08.

PartsAmerical.com: Part number: ABS530079. Price: $ 59.99 as of 5/28/08.

[padgett]

Have gone up a bit and not sure are available. Napa (look like Raybestos numbers):

Front: 530067 $139.69

Rear: 530079 $98.69

Were some BWD ABS600s (front) around but I think the supply ran out.

[Bushwack]

Thanks Ronnie and Padgett. From a labor perspective, how long should it take to replace a pair (front or rear) sensors?

[padgett]

For me, about 10 minutes longer than it takes to change the tires. Have heard of some being hard to remove but has not been my experience.