Hi folks,

Recently got myself a copy of FORScan to aid diagnosing an intermittent ABS issue I have.

When driving I randomly and intermittently getting kickback in the brake pedal when braking, this occurs at all speeds. The wheel sensors appear to all be reading fine, I've also resistance tested them. Attached is the output of my latest test.

-ABS
-ABSTCCVS
-LF_RR_TC_ISO2
-LF_RR_TC_SUP2
-RF_LR_TC_ISO2
-RF_LR_TC_SUP2
-PMP_MTR

The ABS PID is sometimes activating when I am not braking, but more often than not it is activating alongside the hydraulic pump - this is when I get the feedback through the pedal. You can also see the hydraulic pump PID activating at times when the ABS PID has not - again I get feedback during the brake pedal at this time.

Is it normal for the ABSTCCVS (ABS Traction Control Valves - Valve Supply ) to be activating so often? What does this PID tell us?

The ABS dash light never comes during these symptoms and no fault codes have occurred or been stored.

Looking for some guidance on how to troubleshoot this issue further.

Thanks,
G

 

This will be a difficult one to fault find. My guess is that you have a corroded connector somewhere on the system giving intermittent high resistance which is triggering a response from the ABS.

You are going to need a wiring schematic of the full ABS and related parts and then start doing resistance checks. Don't be fooled by doing voltage checks off load, or you might find that it tests good but when underload the voltage collaspses.

 

3 hours ago, unofix said:

This will be a difficult one to fault find. My guess is that you have a corroded connector somewhere on the system giving intermittent high resistance which is triggering a response from the ABS.

You are going to need a wiring schematic of the full ABS and related parts and then start doing resistance checks. Don't be fooled by doing voltage checks off load, or you might find that it tests good but when underload the voltage collaspses.

 

Thanks for the feedback and suggestion!  I had wondered if this could be a poor grounding issue etc earlier in my fault finding but put it to the back of my head.  I'll have a hunt for a wiring diagram and starting checking what I can access easily/visually.

The wiring in the front wheel arches is normally a good place to look.

Hi, Did you find the fault? I’m having the same issue