Cdti abs fault interrupting engine?

biffa75 · 14th December 2021, 17:15

Hi all,

We have a 2004 pre facelift 75 tourer cdti. Since we bought the car in October we have had an intermittent issue.

Issue:
Abs fault flashes up on the ipk screen along with the abs fault warning symbol. This lasts mere seconds but when it does flash up, at the same time the engine begins to lose power (as if the throttle has been disconnected). The Speedo can be seen losing speed.
As said, this lasts mere seconds and goes back to normal with no warning lights and abs works fine.
This can occur at complete random it would appear. It can happen at different speeds. Doesn't appear to be affected by bumps in the road or anything like that either, so may rule out a broken wire?

Because the Speedo was being affected, I figured the first thing to try was the driver's side abs sensor and bearing. Also changed the driver's side rear abs sensor and bearing.

This did not cure the fault unfortunately.

I have also recently been using the on board diagnostics and have been monitoring the voltage.

Normal resting voltage with the fuel pump etc priming is around 11.7v

When driving the voltage shown is between 14.2v to 14.5v

When the abs fault has flashed up, it doesn't appear to affect the voltage displayed (tried this to see if there was a sudden drop in voltage and was causing the abs to throw a wobbler but again, this appears not to be the case).

Has anyone come across this issue before?

I don't believe it is related to an abs sensor or wheel bearing as the abs works fine even after it has flashed up and no lights or issues are displayed afterwards..

I also fail to see how an abs fault can interfere either with the throttle or engine (unsure which) but as said above, when the fault flashes up for example at 50mph you feel the sudden loss of power as if you have taken your foot off the throttle and the Speedo begins to go down before springing back into life and the throttle comes back and all is normal like nothing happened.

On ignition the abs system does its self test and the abs light goes out, the abs works, Speedo works fine and the car brakes in a straight line etc.

Thanks
Rob

14th December 2021, 17:15	#1
biffa75 Trader Mk1 2004 tourer cdti + MK1 2003 Saloon CDT Join Date: Nov 2015 Location: west yorkshire Posts: 502 Thanks: 106 Thanked 91 Times in 57 Posts	Cdti abs fault interrupting engine? Hi all, We have a 2004 pre facelift 75 tourer cdti. Since we bought the car in October we have had an intermittent issue. Issue: Abs fault flashes up on the ipk screen along with the abs fault warning symbol. This lasts mere seconds but when it does flash up, at the same time the engine begins to lose power (as if the throttle has been disconnected). The Speedo can be seen losing speed. As said, this lasts mere seconds and goes back to normal with no warning lights and abs works fine. This can occur at complete random it would appear. It can happen at different speeds. Doesn't appear to be affected by bumps in the road or anything like that either, so may rule out a broken wire? Because the Speedo was being affected, I figured the first thing to try was the driver's side abs sensor and bearing. Also changed the driver's side rear abs sensor and bearing. This did not cure the fault unfortunately. I have also recently been using the on board diagnostics and have been monitoring the voltage. Normal resting voltage with the fuel pump etc priming is around 11.7v When driving the voltage shown is between 14.2v to 14.5v When the abs fault has flashed up, it doesn't appear to affect the voltage displayed (tried this to see if there was a sudden drop in voltage and was causing the abs to throw a wobbler but again, this appears not to be the case). Has anyone come across this issue before? I don't believe it is related to an abs sensor or wheel bearing as the abs works fine even after it has flashed up and no lights or issues are displayed afterwards.. I also fail to see how an abs fault can interfere either with the throttle or engine (unsure which) but as said above, when the fault flashes up for example at 50mph you feel the sudden loss of power as if you have taken your foot off the throttle and the Speedo begins to go down before springing back into life and the throttle comes back and all is normal like nothing happened. On ignition the abs system does its self test and the abs light goes out, the abs works, Speedo works fine and the car brakes in a straight line etc. Thanks Rob