2.2 Hdi: Total Systems Failure! Duff Ecu?

[FridgemagnetC5]

Hi all - first time poster, long time Citroen owner. I'd have liked to earn some karma by posting some tips I've picked up along the way, but I'll have to owe you those for now as I'm desperate all of a sudden.

 

My 2003 C5 2.2 HDI Exclusive flagged up an ESP fault while I was driving yesterday. I parked up 5 minutes later, turned the ignition off and re-started and the fault didn't reappear so I put it down to a random glitch. So I did a bit of grocery shopping, and when I went to start the car up again it wouldn't fire up (though it cranked over OK), and all these faults were flagged up on the display:

 

Missing tyre pressure sensors.

Antipollution fault.

Brake fault.

ESP fault.

ABS fault.

Immobiliser fault.

 

Disconnecting the battery didn't help, and the RAC guy who came out was stumped. The car got a ride home on the back of a flatbed truck, and when I went to move it a few yards by cranking the starter motor in first gear the damn thing started up! It's still showing combinations of all the above faults though, and also the cabin ventilation blower fan is cutting in and out. Sometimes the tacho needle works, sometimes it doesn't.

 

All the fuses in the engine bay are OK, and I've removed, cleaned and refitted all the earth connections on the N/S wing, with no success. To eliminate a bad crimp I've measured the voltage between battery positive and the earth wires (by piercing the insulation) and they all read 14.2 volts (with the engine running). I've also removed all the ECU and fusebox harness connectors, sprayed with a bit of contact cleaner, and refitted. And the fuses too. I see no signs of corrosion or damage on any of these contacts. There's a solid connection between the battery negative and the ECU enclosure (which is connected to ground of the circuitboard inside).

 

So... is my ECU dead then? Or is there something else that can cause such a total systems failure? Any help much appreciated.

[paul.h]

With all that lot you could really do with it connecting to a Lexia diagnostic machine, otherwise it will all be guesswork. On one of the C5 sections there is a pinned list of members who are able to help with diagnostics. On the C5 Technical section there is a pinned list of common problems that may be worth a look.

 

Jump starting another car can give problems, low battery voltage can give errors and prevent starting if the engine does not spin fast enough, quick disconnection/reconnection of the battery can give errors, the pollution fault on the 136 bhp 2.2 hdi could be the swirl flap actuator at the left end of the cylinder head plastic cup connector breaking, it could also be related to the exhaust particulate filter, the apparent brake problems (abs/esp/brake) could possibly be a brake light switch or an abs sensor. Cutting out once warm could also be things like the crank position sensor.

 

I am sure other members will come up with things to try.

[FridgemagnetC5]

Thank-you for the reply paul.h - very much appreciated. Years of owning Citroens have made me very wary of red herrings when it comes to diagnostics, but I reckon there has to be a single cause for all of these faults appearing at once. I was rather hoping it would be a dodgy earth connection that was driving the ECU crazy, but I think I've eliminated that so now suspicion points to the ECU itself.

 

Am I right in thinking the engine management, ESP traction control, ABS brakes and cabin climate control are all controlled by the single ECU module in the C5? The Haynes manual wiring diagrams don't include the ECU. The car isn't flagging up suspension faults, and it still knows if I've got a door open or an unbuckled seatbelt.

 

Am I also right in thinking that replacing the ECU is a major headache, and would involve new keys, ignition switch and possibly some other engine bits and a remapping too? This would be enough to kill the car in this instance, and I'm fighting to save it as I really do like the Hydractive 3+ suspension.

 

I think my only hope is to get the ECU repaired, as it does at least still recognise the key plip signal. This suggests the memory is uncorrupted and hopefully the unit can be saved without having to get the repaired ECU remapped.

 

Addendum: I've just found out I haven't check all the fuses after all, as there seem to be a bunch of "maxi" fuses hidden under the main fusebox.

Edited May 19, 2014 by FridgemagnetC5

[paul.h]

What is the battery voltage before starting the engine ?

Some other things I found on the internet were possibly a blocked or wet air filter which would give the anti pollution but also esp fault since the air flow would not be right, an abs sensor ring damaged for the esp/abs/brake fault and also check if the air con is set to automatic which may be bringing the fan on.

 

Before you look in to replacing or repairing the ecu, wait for any more replies but I can not remember anyone on here having to do anything to the ecu other than possibly trying a bsi reset or battery disconnection/reconnection procedure.

[FridgemagnetC5]

Thanks again paul.h! The quiescent battery voltage is 12.85 volts, and the battery should be a good 'un as I only bought it a few months ago and it gets a regular external charge. The air filter is a K&N that was cleaned about 1,000 miles ago. Setting the cabin ventilation fan speed manually makes no difference, it just cycles between fast and off. I can't believe that all the "faults" that the car display screen lists are genuine, given that they all appeared at the same time and their only common feature is having sensory inputs to the ECU.

 

I've just checked the Maxi fuses (hidden unless you remove the engine fuse box) and they're all OK. There's a relay under the ECU but a bit if research tells me this is just for the glow plugs.

 

I declare the car officially dead. Which is a shame as I've only had it 6 weeks, and I've just bought a full set of steering balljoints and front suspension bushes (but fortunately haven't had time to fit). If it was just the ECU I'd somehow sort it, but it also needs a new flywheel and clutch, there's a small suspension fluid leak in a pipe by the bulkhead, plus some minor bits and bobs. The ECU was the last straw.

 

I'll get another C5 and keep this one on the driveway for a couple of weeks. If I can find a solution to this problem in that time then it'll live again; if not then it's a one-way trip to the local scrappies. A shame, as the 2.2 is a really nice car to drive... almost as nice as my old XM.

[coastline taxis]

Theres a few more checks you can do. but from exprience this sound like a wiring issue or a corrupt bsi unit The fuses that you checked in the glove box has 4 30amp fuses hidden above them. Easiest way is to just remove the glove box to see them. The fuses are part of the bsi unit so check all the multiplugs and wiring going into it. weve seen a few where the main harness int the bsi unit have been rubbing against the brake connecting rod and worn thru the wires and another where passengers feet have pulled wires out. Have you go acsess to any diagnostic tools

[paul.h]

The battery is probably ok but is it the right one for the car since you say you bought it a few months ago yet have had the car 6 weeks and give the battery regular off car charges ? Bear in mind quick disconnection/reconnection can give problems so what procedure are you following ?

[FridgemagnetC5]

Thank-you coastline taxis, that's a very good tip. I haven't checked the passenger glovebox fuses, just the ones in the engine bay, I didn't realise that BSI unit was anything other than a distribution panel/fusebox, so I may have been looking in the wrong place by poking around at the engine ECU. The wiring loom in that area is certainly a disgraceful bit of design though, and I can see how it might be damaged by passenger's feet or the brake link rod.

I might buy a Lexia diagnostic tool this week, as they look like a useful piece of kit to have and I'll be driving Citroens for as long as there are Hydractive suspension models available.

 

Thank-you once again paul.h. The battery was from my previous 2.0 HDI C5 that I part exchanged for my current one, but not before swapping over the battery, wiper blades and K&N air filter. I'm aware that there's a complex procedure for reconnecting the battery but <shameful face> I've never followed it and seem to get away with it. </shameful face>

I generally charge the battery in-situ while it's still connected to the car. I clip on the charger leads while the charger is unpowered and then turn in on at the mains. To disconnect I turn off the mains first and then remove the charger leads. This is probably frowned upon, but I can't see how this method would give rise to overvoltage spikes unless it's a rubbish charger. I never connect/disconnect a charger while the charger is powered by the mains as this would cause overvoltage spikes every time.

 

I'm an electronic designer. "The shoemaker's children are the worst shod."

[paul.h]

Found this which may have some relevance - somebody whose C5 would turn over but not start and came up with immobiliser fault, but when connected to the battery charger it would start which I would think may be a battery problem  http://mendmy.com/answers.php?id=194381

I once checked the current drain on our C5 since the battery would go flat over a few weeks and from memory, found it was about 30 mAmp plus a further 30 mAmp with the towbar relays connected so when not towing I remove the towbar fuses. I think the alarm may have a constant current draw that over time flattens the car battery which I think I read may be worse if its own battery is faulty.

 

Also found this on another site:

Citroen C5 2003

I use my Citroen C5 between short distances. After 4 days I used it yesterday for a 1 km and a half and I parked it. Today when I tried to start it my car did not start and displayed a message "immobiliser fault". It reset the CD player, date and time etc. on the display. I tried a number of times, the result was the same. Could the reason be that the battery charge level is low? (SX 2.0i)

 

Answers

Hello, yes it could cause this fault, a fully charged battery will have 12.8volts but if it is less that 12.2volts it needs charging. Another problem is batteries do not like being flat many times or for extended periods and sometimes this renders them useless as they don’t recharge properly. Also note it is possible to have a fully charged battery that has failed internally that will drop to less than 9.0volts when cranking, if so it needs changing. You must ensure your battery is okay before looking at other faults. Martin (Master technician 20+ years) from England

 

Definitely, the fault is caused by low battery. Recharge the battery or jump start. When you replace the battery, switch on your key for a minute, switch off, switch on again for another minute, switch off again and then start. Trying to immediately start the car after battery replacement or boost won’t work and the immobiliser fault will keep on displaying until the computer finishes initiatising the key recognition

 

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Just a few comments on leaving the battery connected whilst charging, if you are using the car every week or so it should not need charging, as well as a risk of the charger possibly giving a high voltage if not controlled that well (there are chargers that are designed to be left connected) it has been mentioned on here that this would prevent the bsi shutting down since it would be sensing the voltage.

[FridgemagnetC5]

Thank-you for your kind help paul.h and coastline taxis - I think I've fixed it now. I went through the BSI reset procedure, as outlined on this site, and now I'm only showing a depollution fault (I think this latches once tripped and has to be cleared through the diagnostics interface). The BSI must have crashed and scrambled its brains.

 

Alas I fixed it too late to save the car as I need to be mobile and so went out and bought a 2007 2.2 HDi VTR+, which I'm very happy with (apart from the lack of armrests, which I will have to retrofit). It's a beast. I managed to fix the old C5 2 days after I bought the new one...

 

The old C5 will have to go to the scrappies in a couple of weeks as there's too much wrong with it to economically fix. I'm having the parking sensors, K&N air filter, battery, CD autochanger, spare alloy wheel and rear view mirror off it, but if anyone wants anything else then feel free to PM me. It's a 2003 2.2 HDi 138 bhp Exclusive with 100k on the clock. The flywheel, clutch, nearside wing mirror, and intercooler are no good, but the rest is sweet. Interior is cream leather.

[paul.h]

I found the mark 2 C5 handles better than the mark 1 when I changed from a hatchback to an estate, both 2.2 hdi but new one with the higher bhp. The seat material of the mark 2 is not as good though.