As per topic title,  when heading up main road (70mph +), if I hit a change in tarmac or a small bump in the road, the ABS metallic growl sound and I get the traction control light on dashboard.  Only does it at motorway speeds, anything less that 70mph and it doesn't appear.  No difference if conditions are Wet / Dry.  In fact, just came down A9 this morning in torrential rain and nothing has appeared on dash.

Fault also clears with a KOKO cycle of the ignition.

Instrument Cluster isn't playing up, even if I deliver a thud with my hand on dashboard, so I assume there's no Dry Joints present.

 

 

Forscan reporting:

 

===PCM DTC ===
Successful DTC reading, no error codes found

Module: Powertrain Control Module
===END PCM===

===OBDII DTC ===
Successful DTC reading, no error codes found

Module: On Board Diagnostic II
===END OBDII===

===ABS DTC U2023-E0===
Code: U2023 - Vehicle Communication Network Fault

Status:
 - DTC Present at Time of Request
 - Malfunction Indicator Lamp is On for this DTC

Module: Antilock braking system

Diagnostic Trouble Code details

Vehicle Communication Network Fault

CAN communication failure between the PCM and the ESP module.

 

 

Forscan also reports that with "U" faults, do not replace ABS module.

Any ideas where to start?

Suspect a wheel sensor or wheel bearing going down if it's caused by sudden shock.

If it was cluster you'd have loads of lights not just ABS

3 hours ago, DaveT70 said:

f it was cluster you'd have loads of lights not just ABS

Not true. When mine played up all I got was the chime and "Engine malfunction" message. Everything else was normal. It all depends on which joints are cracked. The "U" fault is strongly suggestive of cracked joints.

Resoldered mine myself with leaded solder and no further problems for the last 2 years.

I somehow managed to get a front wheel speed sensor connector damaged even though it’s fairly hidden behind the front strut/hub.

 

Worth checking though I’m fairly certain you should see a DTC logged too?

OK guys, thanks for the replies.

@DaveT70, both front wheel bearings were done with genuine Ford Wheel Bearings at 120,000.

Just been out and Forscan is reporting all 4 wheels at 30mph.  I assume the wheel speed sensors also do ABS?

@troy45 should I whip the wheels off and check wiring to each sensor?  If wiring to sensors OK then reflow Instrument Cluster?

@mjt is cluster removed easily?

appreciated, Bar

Are the rear tyres better quality than the fronts?  Could try swapping front & rear wheels to see if it's a tyre issue.

@TomsFocus, funny enough, fronts are on the limit, rears about 5mm as I always rotate when I change the tyres.  Would that make a difference Tom?

34 minutes ago, Bar72 said:

fronts are on the limit, rears about 5mm

That would do it. 🙁

4 hours ago, Bar72 said:

OK guys, thanks for the replies.

@DaveT70, both front wheel bearings were done with genuine Ford Wheel Bearings at 120,000.

Just been out and Forscan is reporting all 4 wheels at 30mph.  I assume the wheel speed sensors also do ABS?

@troy45 should I whip the wheels off and check wiring to each sensor?  If wiring to sensors OK then reflow Instrument Cluster?

@mjt is cluster removed easily?

appreciated, Bar

I’d get some more feedback ref what DTC you’d be expecting if it was a sensor issue - can’t remember with mine if I’d had a clue from a DTC or was lucky with finding issue on first wheel I removed. The wheel speed sensors are part of the ABS system yes. 
 

In the event of something cluster related it is really straight forward to remove - pull off the trim on top of steering column and you see the 2 Tx25 (I think) screws at bottom of the cluster. Remove these, drop steering column down as far as possible then pull cluster out from the bottom possibly using trim tool to lift top part of the dash at same time. Top of cluster hooks into underside of the dash. Then lift locking bar on electrical connector which will also disengage it from cluster and pull clear. 
 

Easily done and probably a few YouTube videos to help guide you 👍

16 hours ago, mjt said:

Not true. When mine played up all I got was the chime and "Engine malfunction" message. Everything else was normal. It all depends on which joints are cracked. The "U" fault is strongly suggestive of cracked joints.

Resoldered mine myself with leaded solder and no further problems for the last 2 years.

Yes, but you'd get more than just ABS fault codes

12 hours ago, Bar72 said:

@TomsFocus, funny enough, fronts are on the limit, rears about 5mm as I always rotate when I change the tyres.  Would that make a difference Tom?

Yes.  The TC being triggered by a change in surface at speed is usually caused by worn tyres allowing a bit of slip in that situation.

Doesn't explain why the light stays on afterwards, or why there's a CAN fault logged, but that is likely to be the cause of the TC triggering in the first place.

3 hours ago, DaveT70 said:

Yes, but you'd get more than just ABS fault codes

But not necessarily "loads of lights" 😊

Thanks again all for replies.  I've had 4 wheels off and don't see anything obvious.  I'm due to fit front tyres next month so I'll keep an eye on the situation.  I'll update post if anything changes between now and then.