Grand Picasso parking brake wiring fault.

[GiveMeABreak]

Or the wiring to it from either the ABS / ESP ECU

[Stuart W]

My most worrying issue isthat on the system list of diagnostics under the heading of BSI it is showing no connection to the diagnostic regardless of the brake issues.

[Doo]

That amount of errors suggests an earth either not connected or has a bad (corroded or loose) connection. I would go unde the bonnet first and check every connection. If the mechanic lowered the engine, I have experience of wiring harness getting stretched & fine wires snapping inside the plastic sheathing. Certain computers can find the break point in the loom to the millimetre, but as no doubt you are aware, check the easy stuff first. Battery terminals, earth points, and joins on the loom, the + on the BSM (where the feed goes from the battery to the BSM then onto the BSI in most cases). We had such an issue and it turned out to be grotty fuses inside the BSM.

[Stuart W]

Thanks Duo.I have tested the wiring endlessly and there appears to be no hint if corrosion anywhere. I havent yet tried removing the abs plug outer shell to check the other wires.Does anyone know how these come apart without breaking the plastic?The power feed to the bsi was good too.All fuses on the bsi were good and clean.I have removed the BSI again and sent it to Rollingmotion for assessment and reprogramming if necessary..I seems that the engine was only lowered slightly on the drivers side, just enough to access and remove the ABS block. At least I will be able to eliminate the BSI one way or another if it comes back working or no fault found.

[Doo]

Thanks Duo.I have tested the wiring endlessly and there appears to be no hint if corrosion anywhere. I havent yet tried removing the abs plug outer shell to check the other wires.Does anyone know how these come apart without breaking the plastic?The power feed to the bsi was good too.All fuses on the bsi were good and clean.I have removed the BSI again and sent it to Rollingmotion for assessment and reprogramming if necessary..I seems that the engine was only lowered slightly on the drivers side, just enough to access and remove the ABS block. At least I will be able to eliminate the BSI one way or another if it comes back working or no fault found.

If it doesn't look like it comes apart, then it probably doesn't! ABS sensors go into the hub (or close by) and the wire generally goes up behind the inner wheel arch plastic cover. The joint is usually away from anywhere the road grime can't get to it.

Another ABS issue can be the sensor pick up (reluctor) ring. I have seen these snap through build up of rust. May be worth checking, but before that, check the sensor hasn't been forced out of its orifice by a build up of rust. Another common issue with Peugeot (ergo Citroen) is the exhaust pipe "can" melt the wiring running adjacent to it. Might be worth a look there too.

[Stuart W]

I have received the BSI unit back from test with no fault found.Am rapidly running out of options now.Another ABS block of the same number 026956083 has been fitted but not recoded yet but still shows the epb and esp plus service lights.Could it be ECU related since my icarsoft diagnostic shows no communication ABS/ECU.?

[RichardW]

I think you need someone with an oscilliscope and some knowledge of how to use it! It would appear that there is either a break in a CAN wire somewhere, or something is pulling the network down, and chances are it is nothing to do with the ABS. Have a look at Pine Hollow Auto Diagnostics on YouTube, lots of good diag videos where seemingly odd (and unconnected) stuff causes all sorts of mayhem! e.g.

[Stuart W]

Thanks Richard.I have a scope and have already scoped the can bus lines which look normal.I guess it is the data itself which is corrupt in some way. Is the engine ecu involved in the abs canbus data? I havent gone down that line yet since the obd engine related data all seems to be working ok.

[Stuartb863w]

I have the exact same issue you have before changing abs/esp block,

Did you manage to resolve this?