Hi,
I've had my Automatic Omega for 18 months now and all in all it's a good runner, however over the past few days I've had a real problem with all the dials flatlining and then the diagnostic panel saying check automatic gearbox.

Now to start right from the beginning.

When I first got my car there were times when everything was turned on and it would have electrical problems. I had the alternator and battery checked and I was told that they were both fine so I asked them to show me and when I saw the running voltage from the alternator at 13.2v I thought it was a bit low, so I replaced the alternator and that solved all my problems.

Everything was running fine for over a year until last weekend when I was driving along and got stuck in a slow moving traffic jam. Suddenly for no apparent reason all the dials flatlined and then the Auto Gearbox error came up and the car went in to limp home mode. Unfortunately being stuck in the traffic jam in contraflow roadworks I couldn't pull over and stop and the dials flatlined another few times in 30 mins. When I stopped the car and turned everything off it all came back and worked properly again.

I looked on this forum and found out about the paperclip test so I did this and it threw up the following codes:

• 12
• 74 (Mass Air Flow Sensor Voltage High)
• 73 (Mass Air Flow Sensor Voltage Low)
• 49 (Battery Voltage High)
• 31 (No Engine RPM)

I then checked what I could in may stationary car the battery is at 12.6v on idle it goes to 13.6v and at 2000rpm goes up to 13.9v

I drove it for a few days afterwards with no problem but then it happened again. This time when I checked the paperclip it only gave me 49 and 31, which makes me think that 74 and 73 were to do with the first problem before I changed the alternator. I have since been able to keep a closer eye on it and have found the following:

• It only has the problem when the water temperature is above the 95'C mark.
• It only happens when I accelerate.
• The harder I'm accelerating the longer it takes for all the dials to come back.
• The Auto Gearbox Check only appears after the dials have come back to life.

My fluid levels are fine and the coolant and oil was replaced earlier this year. The battery connections feel firm and look clean and the battery fluid levels are all okay.

Please help, I'm hitting a brick wall at the moment.

Regards,

James

The battery voltage high error concerns me. I wonder if the alternator output is a bit high (your readings look fine, but I wonder if it goes high when everything heats up?).

It would be good to get the codes read from the automatic gearbox ECU, as well. If that's also complaining about high supply voltage we have a more conclusive sign.

Thinking a little further, when you say the gauges "flatlined", do you mean all gauges or just RPM? Speedo, temperature and fuel as well? Does the engine actually stall, or keep running?

Any warning lights on the dash when this happens?

Just trying to think through what might be happening.

Would certainly help to get a Tech 2 to it, as then we can look at engine, gearbox and instrument panel for stored codes and live data and maybe spot something.

Definetely sounds like a poor connection somwhere - but where ?
If it was just the dials I would suggest they arent seated properly, and a firm shove on the front might sort it, but I cant see that appecting the gearbox etc.

Sounds like it's overcharging to me. Where in Colchester are you? May be I can have a look over it for you with a code reader next week

Thanks Lazydocker, I have a mate coming over this weekend with an OBD2 reader to see if it works on my car, otherwise I'll take you up on the offer.

Jimbob wrote on 04. Aug 2011 at 09:11:


Typical. I never have an easy car.

So can the diagnostics only be done with the proper Tech 2 equipment?

Just had Lazydocker give my car the once over and it's looking like an overcharging problem, plus I now have a list of things to do for my car 

Thanks again Lazydocker