Activa electrical issues

[Dommo]

Hi folks.

I've jsut been preparing my Activa for it's MOT after not using it over the winter and thought I'd leave it idling on the drive for a while to get up to temperature. After I took my headphones out of my ears I noticed the car was idling on what sounded like only 3 cylinders, with a check engine light on.

I've had issues previously where it did this, but after disconnecting plugs, checking plugs, checking leads, nothing seemed to be amiss. Putting it back together it ran just fine.

I tried Lexia on it today and it came up with the fault code:
"Permanent fault - Mixture adjustment"

Now what I can't decipher is.. Is this fault the cause of the problem, or is this fault an effect of it running on 3 cylinders so the o2 sensor detects a lot of fuel in the exhaust?

I did also have a fault in the Coded anti-theft device, showing as "Fault - Engine control unit connection". Is this fault related? Could it be the keypad has previously been disconnected and a start attempted? I've never cleared fault codes on this car before.

And for completeness, there was another fault in Suspension, showing "Intermittent Fault - Brake pressure sensor". This was cleared. Does anyone know what this means? As it is linked to the suspension ECU I presume it is related to switching to hard mode when braking?

Thank you for any help.

[Dommo]

See attachments if necessary

[Dommo]

Oh and also - can anyone shed any light on why Lexia doesn't communicate with the Airbag ECU? Or the alarm ECU - that doesn't even show up!

I've got random alarm issues which I presume is down to faulty ultrasonics but without lexia I can't confirm which is the problem.

[ekjdm14]

On the airbag and alarm communication issues, I think you're doing well if they're the only ones you struggle with! If the alarm randomly spontaneously triggers unless you disable the volumetric protection then it's likely as you say, one of the ultrasonic sensors. FWIW I'd just replace both if one is iffy, I did find some generic replacements that were suitable so will try and find out what they were again if you don't mind soldering in new ones.

If it still randomly triggers with the volumetric part disabled the problem would more likely be either a flaky door switch or in the alarm itself.

All I have ever seen from the airbag ECU on White was something to do with "lower the hydraulic jack" so I just picked out the shorting pins from the plugs and belled out the wiring till i found the break. If you have an issue there and wanted to try substitution, I have a known good airbag and one of each early and late S1 airbag controllers you could try.
Sorry I can't be more useful on the main problems here, although there have been similar problems with some CXs that have stood idle and that was down to sticking injectors (think it was wurlycorner's cars).

[xantia_v6]

Thee mixture fault is probably a result of the misfire. Pull the spark plugs and see if they are all the same colour to try to localise the fault.

[Dommo]

Slowest reply in the world award goes to me! Apologies chaps but I've had a bit on so I've only been able to partly look into the issues.

First I started with checking plugs, they were all a bit wet, and in removing one it broke into two halves - I assumed this was the fault so replaced with a new set of plugs. However still not firing correctly. Unfortunately getting new plugs fell on the food shop day so we did that with some other odds and sods and by the time I fitted the plugs it was quite late so I didn't get chance to investigate further, and I've been working over the weekend.

Next port of call was to see whether the plugs were actually being told to fire so I bought this tool from Halfords earlier today:

http://www.halfords.com/workshop-tools/ ... ark-tester

This has revealed that the centre two cylinders aren't receiving any pulse whatsoever, so it's running on a whopping two cylinders, no wonder the fuel fumes are so strong. Hope this hasn't killed the cat.

Any suggestions on where to try from here? Is there a way to check if it's the ECU or the ignition coil? The coil is original to the car as far as I can see.

With regards to the alarm, I know my dead white Xantia has two good ultrasonic's in it, so I will pinch those and fit to the Activa and see what happens from there. One thing I have noticed is that the alarm siren doesn't make any noise at all, the way you see the alarm going off is by the headlights flashing on and off!

Thanks guys

[Zelandeth]

What's the setup for this? Two identical coils running a pair of plugs each?

If so, you can probably swap the connections (and HT leads!) over and see if the fault follows the coil or not. This used to be quite a common failure on Lagunas we used to see back when I worked in the garage.

[Dommo]

Unfortunately no it’s one coil for all 4 cylinders, and an ignition module.

https://rover.ebay.com/rover/0/0/0?mpre ... 2464104099

And this:

https://rover.ebay.com/rover/0/0/0?mpre ... 2494348585

Cheers

[CitroJim]

Two coils and wasted spark I believe...

The coil is common to a number of PSA vehicles - my Saxo has an identical one...

The top link is the ignition amplifier and the second is the correct coil by the looks of it...

Coli failure is rare; amp failure not so but again it's a component used widely across the PSA range...

Be sure to use a little heatsink paste on it if it is the cause; they die through overheating due to the heatsink paste drying out.

[ekjdm14]

The alarm on Black does the same (light but no sound) and I believe that part is caused by a dead backup battery in the siren unit, possibly also leaks and damages the circuitry but it's one of the things I intend to sort over this coming year... Typically, the ultrasonics are fine on Black but dodgy on White, who's siren works just fine!

[Dommo]

EK - Once I find the alarm siren box I'll swap it over from my white one to the Activa and see if that repairs itself. I can also have a nosey round for a backup battery and see about replacing that if at all possible while I'm there. It is absolutely typical that you have two functioning halves of the alarm system, but on different cars!

Jim - Thank you for the advice on the heatsink compound, we replaced the heatsink compound, after doing nothing else with it, and it seems to work perfectly well now. This issue has cropped up before and after investigating it, changing no parts - apart from plugs this time because one failed, it now mysteriously works. Very strange indeed. I will certainly be keeping a close eye on it however, as you can pick up both a coil and amplifier for around £40 each brand new for Bosch components, which ultimately isn't a great deal of money.

Thanks very much for the replies and I'll update the post in the future if I have any further issues.

[CitroJim]

Fingers crossed it all holds good now Dom

[Hell Razor5543]

If you have a choice of what type of heatsink paste to use I would (unless it needs to hold parts together) use a silver based thermal paste. It does not dry out, and provides a better heat flow than the white paste (which is why most high powered PCs use it on the CPU heatsink). My cousin, when he applies the thermal paste, spreads it on VERY thinly (making sure the device has a full coating), as the idea of the paste is to mainly get rid of any air gaps between the device and the heat sink. Once he explained it I started doing the same.

[Dommo]

Sounds like the stuff I use on my PC heatsinks. I’ve got some fancy stuff for PC’s but even that dries out after a few years. I’ll keep an eye on this white goop we’ve used but so far so good. I think it’ll all dry out eventually because of its location, it’s out in the open so it gets a good draught