P38A Nanocom vs Wabco C - 97 GEMS

There's been posts around this before, but can't find an answer.

I've got an intermittent ABS light.
I've hooked up Nanocom to start diag, got comms with the WABCO C (no error message), but it reads nothing back - no codes, no wheel speeds no serials - nada.

No problems talking to BCM or EMS, just WABCO.....

Any ideas? - really don't want to start swapping bits when i've theoretically got the kit to diagnose!

Thanks in advance,

Greg

Greg Sharman said:

There's been posts around this before, but can't find an answer.

I've got an intermittent ABS light.
I've hooked up Nanocom to start diag, got comms with the WABCO C (no error message), but it reads nothing back - no codes, no wheel speeds no serials - nada.

No problems talking to BCM or EMS, just WABCO.....

Any ideas? - really don't want to start swapping bits when i've theoretically got the kit to diagnose!

Thanks in advance,

Greg

Click to expand...

Corroded OBD connector is one possibility.

If you have an intermittent fault check the brake peddle switch is set correctly as per RAVE often it is the cause .

Greg Sharman said:

There's been posts around this before, but can't find an answer.

I've got an intermittent ABS light.
I've hooked up Nanocom to start diag, got comms with the WABCO C (no error message), but it reads nothing back - no codes, no wheel speeds no serials - nada.

No problems talking to BCM or EMS, just WABCO.....

Any ideas? - really don't want to start swapping bits when i've theoretically got the kit to diagnose!

Thanks in advance,

Greg

Click to expand...

What age is the vehicle? WABCO C is up till '99 when the 4W TC came in.

Also, thinking about it, some modules work ignition off, some position 2 and some with engine running. Cannot remember which the WABCO one one but cannot see it working off.

Grrrrrr said:

Also, thinking about it, some modules work ignition off, some position 2 and some with engine running. Cannot remember which the WABCO one one but cannot see it working off.

Click to expand...

Good point.

Datatek said:

Good point.

Click to expand...

Ok - now understand it a bit more, if not progressing particularly...

I was trying to read the fault codes when the light had illuminated - unfortunately this is happens above the 2kmph diagnotic threshold, and it doesn't seem to drop back into diagnostics when the speed comes down, so not able to read...and hence couldn't get any info out of the module.

Reading fault codes from a fresh ign cycle gives a 'all four wheels rotation normal' message - I am guessing that if i'd had a wheel speed sensor out i'd see the issue there?.

So - can't read the fault code, but am going to work on the assumption it's dynamic (happens when driving) and that it ain't the wheel speed sensors - so have ordered a switch...

Any thoughts?

Greg

I've not tried this but you MIGHT be able to get a live trace with the Nanocom as you drive along. If you can, that might show something. Guess if it drops out above 5kph then you could try going around a supermarket car-park in low range.

Change the pedal switch or at least reset it. Nanocom will read pedal switch make and break info. There are two elements to the switch one is made as the other one breaks. If they are not making and breaking as they should you will get an ABS fault. Nanocom cannot read functions above 2Km per hour as the diagnostics are turned off until the ignition has been switched off and on. Check stationary with ignition switched on, engine can be running but car cannot be moving.

On Nanocom go to WABCO C > INPUTS > page three, you will see brake switch 1 and 2. One will be closed one will be open. As you press brake they should swap senses they should never be the same sense at the same time.

If it's the switch, the fault doesn't show in the Waco section.

Now you're going to ask where it does. I cant remember but will have a look when I can.

Here we go

NANOCOM - EDC.APP - EDC faults file

BRAKE PEDAL SWITCHES INCORRECT OPERATION
Type: INVALID FAULT,MAJOR FAULT,LOGGED,INTERMITTENT
RPM = 33
WATER TEMP = 74
OCCURRANCE = 7
---

Although that might not help you as mine is a diesel.

gencybay said:

Here we go

NANOCOM - EDC.APP - EDC faults file

BRAKE PEDAL SWITCHES INCORRECT OPERATION
Type: INVALID FAULT,MAJOR FAULT,LOGGED,INTERMITTENT
RPM = 33
WATER TEMP = 74
OCCURRANCE = 7
---

Although that might not help you as mine is a diesel.

Click to expand...

Thanks - unfortunately couldn't get into that menu to get a fault code(function locked?!) BUT based on prior comment, with engine off and live view of the inputs to Wabco, I played with the brake pedal - riding pedal just above top of travel I could repeatably get OPEN/OPEN on the state - so looks like ..... we have a winner!

So new switch in the post, will look up the RAVE procedure and hopefully get it fixed.

Thanks all
Greg

Greg Sharman said:

Thanks - unfortunately couldn't get into that menu to get a fault code(function locked?!) BUT based on prior comment, with engine off and live view of the inputs to Wabco, I played with the brake pedal - riding pedal just above top of travel I could repeatably get OPEN/OPEN on the state - so looks like ..... we have a winner!

So new switch in the post, will look up the RAVE procedure and hopefully get it fixed.

Thanks all
Greg

Click to expand...

Please acknowledge @brianp38dse . He was the one who bailed me out on this one

Please update if the new switch resolves the problem.

gencybay said:

Please acknowledge @brianp38dse . He was the one who bailed me out on this one

Please update if the new switch resolves the problem.

Click to expand...

Will do

Greg