CEL / ABS / Brake pad warning light

[monty77uk]

Hi all,

Just bought my 2nd Boxster .. budget limited due to house renovations so I picked up a late 2003 986 3.2S with just shy of 140k miles on the clock.

History was plentiful and expensive and it is in generally very good condition so I took a punt.

I have the following issues:

ABS/Brake pad wear lights permanently lit
- Pads are fine, replaced all 4 sensors, still lit
- Durametric wont connect to ABS module

CEL .. this is new, only came on last night.

Found the following codes with Durametric:

Motronic 7.8
Current Fault Codes

--------------------------------------------------------------------------------

P0501
Factory Fault Code 120 - Vehicle speed
Open circuit

--------------------------------------------------------------------------------

P2096
Signal delay time for oxygen sensor ageing
Above limit

..the first one, could that be related to the ABS?

2nd one - knackered post-cat o2?

Thanks!
Adam

[JFP in PA]

Originally Posted by monty77uk

Hi all,

Just bought my 2nd Boxster .. budget limited due to house renovations so I picked up a late 2003 986 3.2S with just shy of 140k miles on the clock.

History was plentiful and expensive and it is in generally very good condition so I took a punt.

I have the following issues:

ABS/Brake pad wear lights permanently lit
- Pads are fine, replaced all 4 sensors, still lit
- Durametric wont connect to ABS module

CEL .. this is new, only came on last night.

Found the following codes with Durametric:

Motronic 7.8
Current Fault Codes

--------------------------------------------------------------------------------

P0501
Factory Fault Code 120 - Vehicle speed
Open circuit

--------------------------------------------------------------------------------

P2096
Signal delay time for oxygen sensor ageing
Above limit

..the first one, could that be related to the ABS?

2nd one - knackered post-cat o2?

Thanks!
Adam

Most of this can be related to the P0501 code; that indicates the car has no wheel speed signal, which it gets from the left rear wheel speed sensor. Could be the sensor, the sensor could be jammed up with brake dust (common) a break in the wiring harness, or the AMS module. It concerns me that the Durametric cannot see the ABS module.

The left rear wheel speed sensor can be tested with a multimeter, look for 1.6 to 1.8K ohms across pins 1 & 2 at the sensor. If the Durametric could see the ABS module, you could read the sensor values using it, but that is obviously not possible.

You can also look for a shop with a Baum iScan tool which often can read the ABS system when a Durametric cannot.

[monty77uk]

Originally Posted by JFP in PA

Most of this can be related to the P0501 code; that indicates the car has no wheel speed signal, which it gets from the left rear wheel speed sensor. Could be the sensor, the sensor could be jammed up with brake dust (common) a break in the wiring harness, or the AMS module. It concerns me that the Durametric cannot see the ABS module.

The left rear wheel speed sensor can be tested with a multimeter, look for 1.6 to 1.8K ohms across pins 1 & 2 at the sensor. If the Durametric could see the ABS module, you could read the sensor values using it, but that is obviously not possible.

You can also look for a shop with a Baum iScan tool which often can read the ABS system when a Durametric cannot.

Awesome, thank you, will get the multimeter out tomorrow and report back!

[monty77uk]

Originally Posted by monty77uk

Awesome, thank you, will get the multimeter out tomorrow and report back!

Untitled | Flickr - Photo Sharing!

..take it this means the sensor is shafted?

[JFP in PA]

Originally Posted by monty77uk

Untitled | Flickr - Photo Sharing!

..take it this means the sensor is shafted?

Image is not clear enough to see the range, but if that is above 1.8K ohms, the sensor is out of range.

[monty77uk]

Originally Posted by JFP in PA

Image is not clear enough to see the range, but if that is above 1.8K ohms, the sensor is out of range.

It's mega ohms so miles out.

Does each wheel have a sensor?
Thanks!

[JFP in PA]

Originally Posted by monty77uk

It's mega ohms so miles out.

Does each wheel have a sensor?
Thanks!

Yes, they form the backbone of how both the ABS and PSM/PASM systems determine wheel speed differences.

[monty77uk]

Originally Posted by JFP in PA

Yes, they form the backbone of how both the ABS and PSM/PASM systems determine wheel speed differences.

OK, I'll test them all and report back.

..still odd it wont talk to the ABS system at all though.

Thanks!

[GemballaPhil]

You can always do what I did. Remove the bulb from the dash, I've melted 2 sets of brake pad wear sensors on trips to nurburgring. So I've just taken them off now and took the bulb out.