Hi
Could use some help.
Issue solid ABS light no speedo.
Have my car at the mechanic.
Rear speed sensor issue.
Changed ABS module and both rear speed sensors changed.
Front sensors are fine and sending a proper signal. All cleaned.
Mechanic is telling me we are not getting a signal from both rear sensors.
Which was my original code.
I am getting 3.25 volts coming into all four sensors.

What could cause no signal from both rear speed sensors? With two different sets of sensors?
This is a different left and right same issue.
Obviously I do not have a working speedometer.

Any help would be greatly appreciated.

 

If you mean by "solid ABS light" that the light comes on with the ignition and doesn't go off then that suggests that the ABS module does not see the senors at all (i.e. open circuit).

If the senor is present and has continuity the ABS light will go off as a signal is not expected with the car stationary. An invalid signal would cause an ABS light very soon after you drive off when the module performs another check.

So I'd suggest checking continuity from the sensors to the module. Check first at the module connector for loose/dirty/corroded terminals.

 

Did you know if there is a on site diagram of ABS module harness connector?
That would help me check the continuity at the ABS module, specifically to locate rear speed sensor.

 

I believe the full electrical diagrams are available from the "How To" section. But I've pulled together a few bits of different documents in the attached that should be all you need.

 

Thanks for all your help.

 

Mechanic says he is dumfounded.
All wiring checks out. Sensors check out.

However the no rear sensor signal issue still exists via OBD II so I have no speedometer and immediate abs light. He also ran wires from the rear speed sensors to the ABS module no change.
Any help would be greatly appreciated.

 

Follow up post.
I have my car at the mechanic.

Initially I had a intermittent ABS light after I drove down
a dirt road that was bumpy I was able to clear it after
doing a hard reset and disconnecting and reconnecting the ABS
module harness.
The issue returned after a while. I cleaned all my ABS
sensors and attached and reattached my abs module harness.

The problem became worse now ABS light was on from start-up
and I have no speedometer.

I brought it to the mechanic had no signal from right and
left rear speed sensors and 1095 code from abs module.

ABS module and both rear sensors changed. I am still getting
no signal from the rear speed sensors and no speedometer.
Mechanic has checked sensors and wiring for
voltage/ohms/continuity all checks out. So with old rear
speed sensors and new still no rear speed sensor signal.

Any help would be greatly appreciated.

 

I am suspect of "voltage/ohms/continuity all checks out" BUT, if that is true, then your ABS module has probably failed. "all" is such a strong word...

 

Are you test driving the car or just working on it in the garage?

I noted from the manual that it states the ABS light will not reset after a fault until the car is driven over 12.5 mph.

If you have done that and the Rear Sensor codes persist, and assuming that your tests have eliminated any fault in the plug/pins on the module then it would point to an internal module problem.

If you still have your old module I'd try plugging that in again to see if you still get same codes now that you have replaced the sensors.

Nothing else springs to mind I'm afraid.

 

No codes from module it was replaced.
Frustrating!
No signal for rear sensors.

All the wiring checks performed by mechanic.
He claims there are no wiring related issues.
He also ran a direct wired connection from rear speed sensors to module no change.

 

Well, that would call to question the mechanical arrangement of the sensors to the pulse wheels. Did he "look" back from the module towards the sensors for resistance measurement? A scope on the sensors while turning the wheel is next.

 

Did you check that the reluctor rings are sitting tight and are clean. No crud between the teeth etc?

 

Hi Joedudejag,

I have merged your two threads so all posts related to the same issue are together and I have retitled the merged thread so the nature of the malfunction is stated more clearly. I removed Vanden Plas from the title since the trim level of the vehicle is irrelevant.

If you would prefer a different way of stating things I will be happy to assist.

Cheers,

Don

 

Hi Joedudejag,

Just a few random thoughts:

1. If I recall correctly, only the left rear speed sensor is referenced by the ABS module for the vehicle speed signal that it passes along to the instrument cluster. If you can get your speed sensor problem resolved your speedometer should come back.

2. All four speed sensors connect directly to the ABS module via two wires each, so if your mechanic bypassed the wiring harnesses for the rear sensors between the sensors and modules, it would seem he has ruled out a problem with the rear sensor wiring harnesses.

3. Is the DC resistance of all four rear sensors (old and new) similar?

4. The ABS module uses three grounds, two of which connect to the body at the Left Hand Bulkhead Ground Stud, and the third connects at the Left Forward Ground Stud on the left front inner wheel arch or fender/wing. It might be worth disassembling and thoroughly cleaning those grounds, in case corrosion or looseness is causing high resistance.

5. How exactly is your mechanic measuring the signal from the sensors? Is he using a scope that can read the pulses from the sensors?

Cheers,

Don

 

Thank you for all the help.
It was resolved by my mechanic.
It was the positioning of the rear sensors.
Once the sensors came back online he took care of a 1095 code from the module.

Thanks to all for the help.