2005 9-5 aero cranks but doesn't start. Instrument panel behaves strangely

[rob8055]

Hello to everyone. This is my first post and I apologize for it is a little complicated too so here it goes.

A couple of weeks ago i started my saab and immediately noticed the air bag light stayed on. It stopped running suddenly after few minutes, and it started again with the following attempt. Anyway, I drove the car for few miles and after I parked, i thought I try to fire it up just to check but to no avail. It cranked but no start.

The air bag light stayed on during my journey and when I attempted to start the car, I also noticed that the radiator fan would come on and as soon as the ignition in the ON position and stopped running about 30 seconds after removing the key . Also the rheostat would not dim the instrument panel, only the SID. Another symptom is the green arrows in the instrument panel dont light up (hazard lights on) although the lights outside the car work perfectly.

I did some research before deciding to post this thread and here is the list of all I have checked so far
- all the fuses are OK. (engine bay as well as the ones inside the cabin)
- checked and cleaned the ground points in engine bay. I found four (the one at the gearbox; two by the fender near the battery and another one at the thermostat). Am I missing any other one?
-checked the H42-5 connector for corrosion and it was clean indeed.
-checked the ECU connector and it was clean too.
-checked the iBus wires @ DICE. With the ignition off the the (+) shows 0.9 volts while with the ignition on it shows something like 1.7 but it fluctuates anyway, so not stable. I have read it should be something between 2-4 volts with both ignition in ON and OFF.

The long story short, from what I have read so far, it seems to be a bus wiring problem someplace. Does anyone think I am in the right track? I dont know how to check the iBus (-) wire. I checked the iBus (+) by using a ground point at the door hinge. So it is possible I haven't troubleshooted the iBus properly.

I forgot to mention. The car may run for 2 seconds sometime and then continues to crank only and no start. The battery is being charged as we speak.

And lastly, I know it would be great to have a tech 2 but I think I am the only guy with a saab 9-5 Aero in the whole country (Albania) I have seen few other 9-5s and most of them are diesel as well as some other 9-3 diesels, hence no dealerships and no mechanics/saab specialist. I am on my on really.

Apologies for this long thread and thanks in advance for any suggestion.

Rob

[Mike Brennan]

Albania: Wow, you really are off the beaten path. A lot of us are out of the beyond local help from shops, so you are not alone here. Reading over your post my 1st thought is that you have to find a code reader. They are not expensive, but without one you will never get out of the woods. Often our batteries act charged but in fact are dead, just not enough dead to seem dead. That might be all you are facing. If it is or has a dead cell charging will seem to bring it up but it wont. With the ignition on the battery should have about 12 v and with the engine running over 14v. Check that out first and let us know.

[rob8055]

Hi Mike,
Thanks for your quick reply and helpful advices. I checked the battery yesterday after work . In fact, to be sure that it wasn't the battery, I used another one (same specs) fully charged form another car. The symptoms didn't change at all. I checked the voltage with the ignition ON (as per your suggestion) and it was 11.9 volts. After that I tried to start the car, and it ran for only a second or two and the voltmeter showed something like 13 volts. The car basically just started and shut immediately, so perhaps it wasn't enough time for the alternator to fully charge at 14 volts. I believe there is nothing wrong with the battery since it is very improbable for two different batteries to show the same symptoms.
Again, few seconds after the ignition was ON, the radiator fan started to blow. Definitely, I will follow your advice and buy a code reader but it might delay me by few days. I was wondering if anyone on this forum has experience with troubleshooting the iBus.
Also I would like to mention that last November i did a major work on my car, changed the clutch, sub-frame bushings, gearbox bearings but i am not sure if i may have disturbed any wires. The car ran fine up till now, 4 months after this job.
thanks

[psymon]

Have you verified that your alternator is charging properly? What about your fuel pump?

[rob8055]

Have you verified that your alternator is charging properly? What about your fuel pump?

hi psymon!
I think the alternator works fine. It charged fine after the car started. I havent checked the fuel pump though. I fail to see how a malfunctioning fuel pump can cause havoc to my instrument panel (indicator light dont work, air bag on, light not dimming, door open indicator dont work). Please let me know if I am wrong in my reasoning. However, I have started dismantling equipments/components connected to iBUS in the hope that the fault will lie somewhere in there. From my research so far, it turns out that if the radiator fan starts (ignition on, car cold and not running), means that the DICE does not receive the temperature signal for some reason therefore turns the fan ON in order to protect the engine form overheating. Could it be that the fuel pump may cause all this since it is not that the car simply doesnt star but there are other issues.
Thanks

[psymon]

Your reasoning is fine. I was just throwing out some ideas to check as well as what you had diagnosed. These cars are pretty heavily reliant on the electrical systems and they tend to get all wonky when they arent receiving proper voltage etc. and throw all kinds of lights and codes. It seems like you got a pretty good handle on the matter though. Good luck on the fix and let us know how you make out.

[T4hir]

Trickle charge your battery for a couple of days or at least 16 hours minimum..........

[rob8055]

PROBLEM SOLVED!
Hello guys and thanks for the ideas and the support shown to solving this issue. Most of all, discussing problems on forums helps for brainstorming as well as not loosing hope :-)
After some 5 weeks since the problem occurred, and working only on weekends, yesterday I found what the problem was. It appears I was on the right track assuming it was the IBus giving me troubles. It turns out, it was the connector behind the Main Instrument Unit (aka Instrument Cluster) which, for some bizarre reasons was loose and the pins of iBus going to the DICE made no contact.
However, I have to make some points for anyone who is unfortunate enough to have this problem in the future, that the symptoms are essential in diagnosing the problem. Always start form the most simple and easy things to check. As the other guys have mentioned, the battery might be problematic so before any diagnostics begin, the battery MUST be in top condition. Check the ground points, fuses and so on. Then, if satisfied with the troubleshooting, carry on with the Bus diagnostics. However it is essential to understand how the Bus system works and the wis is also a must. I ended up disconnecting everything inside the car (DICE, SRS, SID, Radio, ACC, CD changer at the boot) and measure every single connection for open/short circuits. If any problem in the IBUS, there is very likely that more than one function/thing/instrument, won't work since it is very sensitive to voltage (like my case). Then, when doing measurements from the ECU to the DICE, no connection showed which led me to the MIU. I read a lot how the iBus works and how to troubleshoot it (recommended before starting diagnostics) and although it seems complicated at first, once you grasp the main idea, it becomes more clear how to troubleshoot it and how to interpret the results.
Hope this helps even if for a little to anyone who might need it and sorry if it is a little general. I haven't covered how to do the dismantling of the components mentioned above, and mos of all, the dashboard, all of which are not very difficult plus there are many posts on the internet. Will try to help if anyone needs my experience.
Once again, thanks for your help!