Peculiar 308SW Braking Fault - Desperate help needed!

[RyanArthur]

Morning all,

I've got a 2014 T9 308SW 1.6HDi which recently started declaring 'Engine Fault - Repair Needed' or something to that effect every time I braked. When I lift my foot, the fault goes away and the 'Eco Active' notification displays for a moment. There appears to be no problems with actual braking - all callipers appear to be free, no fluid loss, no apparent loss of vacuum, no declared ABS issues or anything like that. I ignored it at the time as I need the car to commute and can't really afford to have it off the road or spend endless thousands replacing every electrical component in the car in the hope of eventually hitting the right one, but soon after that started the electric parking brake started having problems too - this appeared to be permanent and has at least 3 orange lights on the dash..

I had a friend check the diagnostics - various codes appeared including the nearside EPB motor, so I thought that must be the problem. Waited over 2 weeks for Evri to deliver a replacement, threw that aboard but it changed nothing - diagnostic machine couldn't initialise the new motor due to the braking fault too, and the fault itself of course continued exactly as before. "The initialisation procedure is complete but a problem occurred. There is a fault relating to the motorised brake calipers" - the diagnostic kit can't make either motor move in either direction.

I've replaced the brake switch behind the glovebox, have tried another (good) battery, have cleaned up all the fuse connections on the power distribution board (I don't know the correct name) on the front of the battery etc. Can't see any obvious loom issues from the EPB motors although it was only a quick look from what I could see with the wheels off.

The only other things I can think of is occasionally the cruise control wont work - it just displays a flashing '--', and the stop/start thing has never worked in all the time I've owned the car. The latter I never expected to be an issue as we also have a 2020 308SW with stop/start which doesn't work either but there are no other faults with that one.

From the diagnostic machine, the VIN number is VF3**************[VIN obfuscated, can be read by forum staff] - I don't know if that's correct or some generic thing it pulls for the model.

When I pulled the codes last night I got the following:
BSI:
U1F00 - Fault event not stored in the faults log - permanent
B132A - Air con circuit low pressure safety fault - permanent
U1F41 - Absence of communication with the supplies protection and management unit - intermittent
U1F3C - No communication with the diesel additive pump - intermittent

Engine ECU:
P1445 - The FAP must be changed - permanent
P0409 - EGR jammed shut during sleep phase - intermittent
P1435 - Multiplexed additive pump fault - intermittent
U1133 - LIN Network - reversible alternator is confirmed absent - intermittent
U1134 - LIN Network. No comms with voltage retaining device - intermittent
U1400 - Alternator LIN network - Fault registered - intermittent

ABS/ESP:
C156C - Electric parking brake (FSE) actuator sensors - Intermittent
C1560 - Electric parking brake (FSE) left hand actuator - Permanent (This is the one I replaced new...)

Power Steering GEP:
B1644 - Power supply fault - open circuit - Intermittent
B1406 - Overheat of power steering motor or ECU - Permanent
P0562 - Power on fault - not characterised - Intermittent

Multifunction Display:
U1F3E - Absence of comms with telematic unit - temporary
U1F18 - Touch screen not communicating on multimedia CAN - temporary

Instrument Panel:
B1003 - Secure config fault - Permanent

Of course many of these may relate to having had the battery off. I left it disconnected overnight before hooking up a decent new (albeit slightly smaller) battery.

After clearing the above and re-reading the codes, the ones which immediately remained were:
Engine ECU - B1445, U1133, U1134, U1400
ABS/ESP - C156C, C1560
Instrument Panel - B1003

My MoT is up, I'm having to borrow cars to get to work. Out of money, time and ideas. Would be eternally grateful if someone could point me in the direction of where to start hunting these faults down...

[PaulC5]

How many miles has the car done, was the dpf fluid topped up in the last few years (thinking if it has run out the dpf might be blocked giving P1445) ?

Sometimes a bsi reset can clear odd electrical faults so if not already done is worth a try viewtopic.php?t=61997

The caliper motor, I assume you replaced the left hand one when looking from the back of the car to the front.
This topic on a C4 Picasso suggests a software update might fix C1560 but a pity the posters did not come back saying if their faults were fixed and how. viewtopic.php?t=75808
Another topic where it was damaged wiring but is for a C4 Picasso but it could suggest you need to check your wiring. viewtopic.php?t=64916

[RyanArthur]

Appreciate your response Paul many thanks.

i can't recall the mileage off the top of my head but it must be over 120k. Haven't filled the DPF fluid in the <1 year I've owned the thing so I couldn't say. It doesn't have the Adblue system my 2020 version does so I assume its in a bag hidden away under the car somewhere..

I did replace the left EPB motor, and when that didn't change anything I put the original left one onto the right side in case the signals were confused.. Neither changed a thing. I checked the wiring on the right side as much as I could see from the wheel arch on the drive, but will need to check the left side again also as I didn't give it a close look at the time.

Will try that BSI reset too - appreciate all your suggestions!

I'm hoping someone might have seen this engine fault on braking issue before and maybe have a fix, but totally at my wits end with the blasted thing.

Thanks again chap.

Cheers,

Ryan

[RichardW]

I suspect this will be the same as the C4 Picasso with a broken wire - you need to get the wheel off and pull all the wiring out the conduit as far as you can - often they rot off and break near where they enter the car. You may be looking for a small rot spot.

[RyanArthur]

I suspect this will be the same as the C4 Picasso with a broken wire - you need to get the wheel off and pull all the wiring out the conduit as far as you can - often they rot off and break near where they enter the car. You may be looking for a small rot spot.

Thanks Richard.

Do you know if that could be replaced by a section of loom I could unplug or is it spliced into the main harness etc?

[RyanArthur]

Oh - another question - the Haynes online manual for this thing helpfully tells me how to test each wire from the parking brake motors back to the ESP module, but it neglects to mention where to find the ESP module.. If anyone could point me in the right direction there it'd be much appreciated also!

[RichardW]

On the C4 there is a connector under the rear seats somewhere, so in theory you could replace that loom section, but if you find a break just repair it.

[xantia_v6]

Oh - another question - the Haynes online manual for this thing helpfully tells me how to test each wire from the parking brake motors back to the ESP module, but it neglects to mention where to find the ESP module.. If anyone could point me in the right direction there it'd be much appreciated also!

i believe that the ESP ECU is actually the ECU mounted to the ABS block in the engine bay.