System Fault Message on Volvo Engine EVC

[battuta]

Hi folks,

I'm hoping one of you can help me. Three days ago I suddenly got a "System Fault" icon (triangle with an exclamation mark in it) and alarm on the EVC tachometer display of my Volvo D1-20. The engine is running fine, and has done so since, but the alarm is persisting every time I start up. I can silence it, but the icon remains on the display...

The manual says this error comes up when there is a short circuit or chaffed lines, but search as I might for what is easy to see (including disconnecting/reconnecting all the connector plugs and sensor connections) I haven't found anything amiss.

Anyone else had a similar problem and fixed it, or have any suggestions for me? Short of inspecting all the wiring from the helm to the engine (a bit of a heinous job, to say the least) I'm not sure what to do here.

Thanks in advance.

Riyad (sleepless in Vancouver, Canada)
2009 B31 Cruiser "Battuta"

[dawntreader]

I had a similar problem and couldn't find any faults. However, I did find a corroded alarm control unit connector block on the wiring loom - see attached. I cut both sides off and replaced with bullet connectors. No alarms since (2 years since repaired).

[battuta]

Thanks so much for this info and photo Dawntreader! You've inspired me to look again and closer at all those connections.

From your photo it looks like that corroded connector block you found was in the helm console, is that right? And was it out in the open, or hidden under heat shrink tubing?

I thought I looked at all the connectors back there, but I might have missed something...

[dawntreader]

It was loose but inside the binnacle at the helm. Water must have tracked along the wires and into the connector block. When the alarm became persistant I couldn't find anything wrong and in the end the only conclusion was a faulty alarm. The block looked ok from the 'outside' but it was when I pulled it apart that the corrosion became evident.

[battuta]

Thanks for this additional info and the photo Dawntreader!

I spent about 3 hours today tearing open the entire helm console and binnacle, plus tracing the wire loom back to the engine and electrical panel Pulled apart and inspected every connection, plus all of those on all the sensors plus the CPU at the engine itself. Unfortunately no corrosion or visible problems and the alarm is continuing...

If you (or anyone else) has any other suggestions please do let me know. I'm starting to run out of hope that this will get solved.

[dawntreader]

I'm sorry you didn't find any 'obvious' issues with your wiring. I can emphasise with you, having had a similar problem. Mine was intermittent and the alarm would stop for months before returning. I took comfort in testing the conditions that should trigger the alarm by testing outputs and performance. In my case the battery alarm was sounding - randomly on occasions, sometime persistently on start-up. However, the alternator output was exactly as it should be; the batteries didn't run flat; and the drive belt was correctly tightened. 'Stepping back' I asked what had been changed recently that might cause this - the answer was 'nothing'. I concluded the alarm was not due to a system failure but rather one due to the alarm system not seeing the 'correct' conditions. That was a real issue for me as I don't know what the correct values should be. The handbook suggests the voltage output, oil pressure values and temperature range but is not specific about how the alarms will trigger. Without the engine running, the warning lights behaved normally. I found a wiring schematic on line but this only served to prove which wire was connected to a specific alarm circuit. I am not sure that what I did by cutting out the block specifically solved the issue but, in between voyages, it stopped and hasn't returned. That was two years ago - I dread hearing that beep again. If I do, I will engage an electonics expert next time.

[CRYSTAL]

Not much help but this is from their installation manual....

Check for short circuits or broken cables / chuffed cables.

have you tried removing the oil /temp connectors for testing to see if u get the right alarms?

and post some nice pics of Vancouver / False Creek marina and RVYC.

[battuta]

Hi Folks,

I thought I'd send a follow-up, as I managed to solve the problem and the unexpected root cause may be helpful to anyone else who has a similar issue in the future...

A post on the "Cruisers Forum" led to a person writing back who had a similar problem that was solved by a mechanic in Martinque and ended up being burned out glow plugs. Then last week I had a very difficult engine start that made it clear, as did some subsequent testing with a multimeter, that the glow plugs were not functioning and were not being supplied any power. I initially thought the problem was with the "black box" CPU for the EVC system (an $850 item), as it has a non-servicable relay in it that sends power to the plugs. Turns out though that the EVC unit actually tests the circuit on startup, and if it detects an open circuit, it triggers the vague "system fault" alarm (and presumably will not then send power to the plugs when the button is depressed even after the alarm is silenced). How though, you might ask, could all 3 glow plugs burn out simultaneously to lead to this situation? Well the answer, I think, is that they did not. Rather they likely failed sequentially over months or even years (and I had noticed the cold weather starts were getting more difficult), but only when the 3rd and final one burned out did the mysterious alarm go off. One way to test this theory is simply to ground the current bar (supplying the positive power) to the glow plugs when a system fault alarm goes off, and when I did this the alarm silenced (as the open circuit was eliminated). And so with this presumptive diagnosis in mind I went ahead and pulled all the glow plugs and discovered that they all had infinite resistance on ohmmeter testing, and none of them lit up when hooked directly to 12v power.

So 3 new glow plugs have been ordered, and the problem is hopefully solved! If things STILL aren't working after this, I may need to replace that EVC black box after all, but hopefully not. Needless to say, even the electrical workshop manual for the Volvo EVC system does not explicitly explain the possibility of what I've described above. Gotta love all that fancy electronics - it's wonderful until something goes wrong and then the troubleshooting can be quite problematic to say the least!

Thanks again to those of you who jumped in with helpful suggestions. And if you're interested, below is a link to the reply I received on the Cruisers Forum about this issue (it has some additional details that may be helpful, and the ultimate issue which was the same as mine is revealed at the end of the thread):

http://www.cruisersforum.com/forums/f54/mysterious-system-fault-warning-138607.html

-Riyad