S60 Electrics: Intermittent/dead DIM and misfire - SOLVED!

[namtip]

Hi all,

I bought my S60 automatic about 3 weeks ago now, and the previous owner was very honest in telling me about the intermittent cluster problem. When test driving the car I could whack the dash and the gauges/display would jump into life for a short time before going dead again. Just a loose connection I remember thinking at the time....!

I work at a PCB manufacturer, so I know quite a lot about electronic assemblies, soldering, and fault-finding etc. But my gosh this did my head in. It is solved now, and so wanted to pay a bit back for being a lurker by writing my findings up for others who are in the same situation.

I started with google and youtube, which all seemed to point to resoldering the chips and other surface-mount components on the DIM PCB. I did all this, and put back together, and lo and behold it worked. The dash lit up, all gauges, messages, and LEDs worked. A couple of the gauge illumination bulbs weren't working, but as I had already fixed it back into the car I couldn't be bothered to test the bulbs and just assumed they were blown - I wasn't bothered.

Last weekend I drove to the supermarket, but then starting it up to come home again, the dash was again dead - no illumination, nothing. The indicator lamps worked, but only the left lamp flashed no matter which way I indicated (the external lights worked fine).

I took the PCB out again and set about trying to find the root cause. I plugged only the PCB back into the loom and after much experimentation found that if I flexed the board at a point between the right indicator lamp and component TR3 (a MOSFET that switches power to the illumination when receiving a signal from the Yazaki FPGA chip), it would spring into life momentarily. However when I released my grip, it would freeze in its current state - even to the point where I could take the keys out and the dashboard would stay illuminated. Only disconnecting the battery would reset it.

I had my colleague have a go at resoldering the chips again with a hot air reflow station, to no avail - still dead. At some point I tried starting the car because I needed to go somewhere (up till now the engine had always run ok even with the faulty cluster), but this time it had a shuddering misfire and wouldn't rev above 1500 RPM. I couldn't read any error messages as the cluster was dead!

I was thinking about torching it at that point. Instead I decided to throw money at it and took the cluster to Cartronix in Waterlooville for them to look at. They not only have all the soldering expertise etc, but had all the equipment to exercise the cluster (CAN bus etc). (Disclaimer - I do not work for or otherwise have anything to do with them) Their website specifically described the common problems with the S60 dash and said that they could repair it and gave a lifetime gaurantee. One hour after arriving I handed over £120 and they handed me back my fixed cluster. I asked them what exactly they did to fix it, and the technician said that he had totally replaced the Motorola processor for a new one and had reprogrammed it. He had also replaced all of the resnets (resistor networks - small surface-mount resistor packs).

Got it home, plugged it in, reconnected the battery, and... perfect! It worked perfectly - even the illumination bulbs that I thought had blown had either been fixed or replaced. The engine however still had the misfire problem.

I remembered that I had bought a cheap bluetooth ELM scanner for a previous car, so I dug it out, downloaded an app to read and delete codes ("Torque" on Android - but there are many others). The app said there were no fault codes stored in the ECU which was strange, as there was something definitely wrong. I clicked on "Clear Fault Codes" any way, and app didn't really do or say anything. But on turning the key again the engine ran perfectly!

Took it for a test drive and now is working perfectly! Will update if anything goes awry...

[100K+]

I suspect your original DIM issue was one of the 20/80occassions when you need the right expensive equipment as well as the right learned knowledge to resolve the issue. We all can share the knowledge through the forum, the expensive equipment is another matter.

Cheers
Bob

[Georgeandkira]

Your experience was so good I'll send any DIM to that firm with confidence--even if it is across the water far, far away.
They replaced an IC and had a chip burner on hand....impressive!

Adds another dimension to burnt out gauge illumination bulbs, doesn't it?

[namtip]

Dashboard is still working!

However I had the engine misfire again this morning. I cleared the fault on the 'Torque' app I downloaded while the engine was misfiring. As soon as I touched the 'clear faults' button, the idling went back to normal and the 'reduced engine performance' display went away.

I had to go to the post office later the same day (today). This time the car started and went fine with no smartphone intervention.

However on leaving the post office - again the misfire on startup. Again I was able to 'clear faults' via my smartphone and the idling went back to normal and full power was resumed.

Very strange!!!!

At no point has the fault showed up while driving.

I'm going to start logging when this fault appears, along with anything else I happen to notice. It might help to build up a picture of what's going on.

Does anyone have any suggestions of things to check/clean?

[V70Craig]

I wouldn't trust the Torque app to show all codes, I used it on my 02 T5 and despite knowing there ARE codes stored it showed none.

Thanks for the heads up regarding where to try for a DIM fix, I'll certainly consider them if I ever have that problem