[Brakes] Yet another ABS fault

[leftfootleashed]

B9 1.6 *petrol* here (think the ABS system is the same as the 1./6HDi though?). Got an ABS fault warning last weekend - terrible timing since the MOT expires tomorrow. Plugged my generic OBDII reader in and got front right sensor fault.

Managed to get a new Delphi sensor fitted yesterday - scraped out the rust from underneath, cleaned the sensor ring up and greased under the sensor. Cleared the fault with my OBDII but it comes on with the ignition now (whereas before it only came on intermittently).

I've borrowed my mate's Diagbox - hoping maybe it needs a reset that the generic OBDII can't do?

Could obviously be a wiring fault - any tips on where to start looking? Is there an ABS module somewhere or is it part of the main ECU?

Cheers

[shtu]

I'd go on with Diagbox and clear any ABS faults before panicking.

Whne the ABS relay failed on mine, I had to clear faults before the ABS warnings would stop, they did not self-clear.

If that doean't work report back what the fault(s) are.

[leftfootleashed]

I'd go on with Diagbox and clear any ABS faults before panicking.

Whne the ABS relay failed on mine, I had to clear faults before the ABS warnings would stop, they did not self-clear.

If that doean't work report back what the fault(s) are.

Cleared on Diagbox and started up - no fault. Thought maybe I was in the clear, but took it out for a spin to check. Light came back on before I got to the end of the street. Thought it wasn't suppose to do anything below 30mph!

Left it till tomorrow when it should be drier. Didn't check the fault code again, but previously it was right front sensor coherence (C1331 iirc).

[leftfootleashed]

So the ABS light is now off.

Took the arch liner out and the cable housing off to look for damage - nothing. Tested the circuit resistance at the socket - OC. Took the other side off to compare - socket is also OC.

Had a closer look at how the sensor was mounted. Despite chiselling and wire brushing all the rust off, the sensor seems to fit further from the reluctor ring than it should when the bolt is nipped up. Did some more scraping, refitted and turned ignition on - still a fault. Hooked up the Diagbox, cleared and restarted - still a fault.

Took the sensor off again. Attacked the recess with various implements, including a freshly sharpened (old) chisel. Still not completely happy with how it's sitting, but better. Found the screen on Diagbox where you can monitor the sensor reading live and checked it read when the hub was rotated.

Started it up and got "braking system fault" and the STOP light on! Fired Diagbox up again and it wasn't showing any faults from the ABS, so put the wheel back on, started up and took it round the block. Light off and stayed off. Low confidence in it not coming on on the way to the garage for the MOT tomorrow, but fingers crossed.

[shtu]

That really is a stupid design, isn't it?

When I've had them out for other reasons, a hammer and cold chisel was the way I managed to clean them up.

[leftfootleashed]

That really is a stupid design, isn't it?

When I've had them out for other reasons, a hammer and cold chisel was the way I managed to clean them up.

There must be a better way. The single bolt allows for too much movement. 

Another year's MOT. Feels like a miracle every time!

[Multispacer]

Well done for getting it through another MOT. Yes, the sensor and housing, really is a rubbish design on the B9, I've even had the single screw seized before and had to drill it out! [That was fun, not!] After that episode, I went around and applied anti-seize compound to the threads on all the sensor screws.
Out of interest when you used the diagbox you borrowed, were there any other fault codes other than those directly linked toi the ABS sensor? And another question if I may, what was the generic OBDII reader you were using originally, as most do not work with Citroen vehicles?

[leftfootleashed]

Well done for getting it through another MOT. Yes, the sensor and housing, really is a rubbish design on the B9, I've even had the single screw seized before and had to drill it out! [That was fun, not!] After that episode, I went around and applied anti-seize compound to the threads on all the sensor screws.
Out of interest when you used the diagbox you borrowed, were there any other fault codes other than those directly linked toi the ABS sensor? And another question if I may, what was the generic OBDII reader you were using originally, as most do not work with Citroen vehicles?

Thanks. Needs a new water pump (leaking) though, and replacing the corroded clutch pipe is going to be a bigger job than I thought 

The bolt was properly seized. I soaked it in Plus Gas and cut a slot in and tried to hammer it round with a punch but it wasn't happening, so I removed the sensor in several pieces with a hammer and chisel and got a Vice Grip on it which thankfully did the trick.

There were a couple of other fault codes: one or two I think relating to the fact I've replaced the original stereo, and one for the high level brake light (which was odd: checked and none of the brake lights came on, and I couldn't do anything about it anyway, so I just left it to the garage, but they didn't mention it. Should really check again but I can't believe they'd have given it an MOT without them working).

Not sure it helps, but I bought this OBDII reader for nine quid off Amazon, in 2017: https://www.amazon.co.uk/dp/B00PJPHEBO/r...71_TE_item
It seems to be fine for reading and clearing fault codes and lives in the glovebox.

[Multispacer]

Well done for getting it through another MOT. Yes, the sensor and housing, really is a rubbish design on the B9, I've even had the single screw seized before and had to drill it out! [That was fun, not!] After that episode, I went around and applied anti-seize compound to the threads on all the sensor screws.
Out of interest when you used the diagbox you borrowed, were there any other fault codes other than those directly linked toi the ABS sensor? And another question if I may, what was the generic OBDII reader you were using originally, as most do not work with Citroen vehicles?

Thanks. Needs a new water pump (leaking) though, and replacing the corroded clutch pipe is going to be a bigger job than I thought 

The bolt was properly seized. I soaked it in Plus Gas and cut a slot in and tried to hammer it round with a punch but it wasn't happening, so I removed the sensor in several pieces with a hammer and chisel and got a Vice Grip on it which thankfully did the trick.

There were a couple of other fault codes: one or two I think relating to the fact I've replaced the original stereo, and one for the high level brake light (which was odd: checked and none of the brake lights came on, and I couldn't do anything about it anyway, so I just left it to the garage, but they didn't mention it. Should really check again but I can't believe they'd have given it an MOT without them working).

Not sure it helps, but I bought this OBDII reader for nine quid off Amazon, in 2017: https://www.amazon.co.uk/dp/B00PJPHEBO/r...71_TE_item
It seems to be fine for reading and clearing fault codes and lives in the glovebox.

The reason I asked about other fault codes, was in my last year of B9 ownership, I had some electrical failures [the first I noticed was the rear wiper not working] and then started to get a load of fault messages regarding ABS, as well as the STOP message coming up and my fault [on that occasion] turned out to be nothing to do with the ABS system at all.

After a lot of fault finding my problem [and looking around on line this affects a number of PSA group vehicles not only Berlingo models, so a bit of a design fault] was the engine bay fuse box. The thing is it is not just a fuse box but also has a circuit board on the base that communicates with the BSI. This is prone to water damage, reasons being either the scuttle drains at the ends of the engine bay get blocked with leaves and other debris [you need to take off the wipers and the plastic scuttle cover to check these are clear] and when these are blocked the excess rain water goes into the engine bay and goes straight onto the fuse box/circuit board causing all sorts of warning problems or faults.

In my case, it wasn't actually rain that caused the problem, what had happened in my case was that a rodent had taken up residence in my engine bay fuse box and used the area as a toilet and completely killed the circuit board. It turns out even with the lid on there is enough of a gap where the looms go into the box for small rodents and water to get in!

To check for indications that your engine bay fuse box has been affected by liquid damage of some kind is to make sure the vehicle is in 'sleep' mode, ie if you have started it make sure you leave it a decent amount of time for everything to shut down [5+ minutes] then disconnect the battery, then take the lid off the engine bay fuse box [it is adjacent to the battery] and pull each fuse out one at a time and check for any corrosion on the legs of the fuses. If there is any evidence clean off the corrosion from the legs and spray the legs and the socket that it plugs into with ELECTRICAL CONTACT CLEANER [make sure you only use electrical contact cleaner as other substances like WD40 can cause all sorts of problems on electrics] Some users have reported that just cleaning up all the fuses and sockets fixed their problems.

In my case though, as stated, the underside circuit board was dead due to rodent abuse! The only good thing is that if you do have to go down the road of replacing the whole board [it comes complete as a fuse box/cicuit board] it is a simple DIY job and no coding/programming of the unit is required.
I ordered a used unit from a supplier on Ebay [it was about £40 delivered] and it took only about 20 minutes to change.

The one thing you must make sure you do, if you go down the replacement path, is that you get the EXACT same part number of box as a replacement, as the boxes have been used on a large number of different PSA group vehicles that have different functions depending on model and are not all interchangeable.