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Limp home mode / low voltage? 

 

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 Post subject: Limp home mode / low voltage?
Posted: Fri Jun 11, 2010 2:54 pm 
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Just got my car back after a month at the panel beaters and the battery had to be jumpstarted for me to drive it home. Then discovered the car is in limp home mode and the air bag light is flashing code 52. Seeing as 52 relates to low voltage regulation warning, I suspect that this low voltage issue is the cause of the transmission being set into limp home mode as well as initiating the airbag warning.
So I threw the meter on the battery and checked the charge rate and discovered the voltage initially starts at 14v and drops to 12v whilst idling after a minute or two. I suspect the alternator is no longer functioning properly.
I just wanted to confirm that low voltage can cause limp home mode?

 

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 Post subject: Re: Limp home mode / low voltage?
Posted: Fri Jun 11, 2010 3:44 pm 
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it did for my car i was told by raa when they checked it

possibly the bushes on the alternator having not been moved for 1month have stuffed up causing your alternator to stop working

 

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 Post subject: Re: Limp home mode / low voltage?
Posted: Fri Jun 11, 2010 4:16 pm 
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Yes it can cause limp home mode.
I've read it in the workshop manual.

 

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 Post subject: Re: Limp home mode / low voltage?
Posted: Fri Jun 11, 2010 4:28 pm 
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Ok thanks, now I need to sort out another alternator and clear the airbag code and the car should be back to normal.

 

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 Post subject: Re: Limp home mode / low voltage?
Posted: Fri Jun 11, 2010 8:27 pm 
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Been told to check this business for a suitable alternator: http://www.cooldrive.com.au/search.aspx
I located the following part number: 65-0007 and when I look it up on their search engine above, it came back with a 110A alternator for the EL.

 

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 Post subject: Re: Limp home mode / low voltage?
Posted: Fri Jun 11, 2010 11:24 pm 
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Limp home should fix itself hopefully - check for fault codes if it doesn't(you know the drill).
I wonder if the alternator reg is playing up - the alternator itself is usually not too bad(windings and diodes). Maybe swap over another reg from someone else's V8 to test this - I wonder if the I6 regs are the same ?
The alternator casings are different I6 v V8 ??
Run the car at fast idle, and turn headlights on, check voltage before and during, and see what you get.

 

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 Post subject: Re: Limp home mode / low voltage?
Posted: Sun Jun 13, 2010 7:09 pm 
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Whilst I sort out this low voltage issue, I decided to temporarily fix the transmission problem by pulling the transmission fuse so as to reset the auto transmission and regain all gears. This seems to work four out of five times.
But, I noticed something interesting when I pulled the auto fuse - the thermo fans. They seem to always be running flat out, even when the motor is running cool. As soon as I pull the auto fuse, the thermo fans stop and when I put the fuse back in, the thermo fans turn back on to flat out regardless of engine temp being cool.

 

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 Post subject: Re: Limp home mode / low voltage?
Posted: Sun Jun 13, 2010 7:13 pm 
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is it possible to blame the mob that had your car for a month.......considering these problems were non-existant before they had there hands on it?
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 Post subject: Re: Limp home mode / low voltage?
Posted: Sun Jun 13, 2010 7:16 pm 
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have you by any chance checked the fuse block and fuses for the fans in front of the air box?

because i always thought "Wouldnt one normally come on for air con and the other if the engine and transmission get hot?" so it might even be shorting to somewhere. Other than that, im hopeless so sorry if i couldnt be much help

 

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 Post subject: Re: Limp home mode / low voltage?
Posted: Mon Jun 14, 2010 9:05 pm 
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AUTO TX fuse powers the thermo relay coils from memory - hence them shutting down.
If engine temp looks okay on the gauge, sounds like trans temp is causing the fans to run flat out.
Like the engine coolant plug, if there is an open cct in trans temp, the fans will run flat out (IIRC that is).
Unplug the circular plug at the transmission, clean if necessary, and plug back in.
As I've said earlier, this should show up as a fault code, and will cause LHM.

 

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 Post subject: Re: Limp home mode / low voltage?
Posted: Sat Jul 03, 2010 3:24 pm 
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Last week I pulled the two engine loom plugs out from behind the motor and checked them out. Found some corroded pins and cleaned them up and then cleaned up the rest of the pins as well before reconnecting them. Next morning with the temperature stone cold, I started the car, selected drive and found the transmission fault was still there. Bugger.
Today, I had access to a code scanner to check the codes on the ECU. Amongst a bunch of other error codes for other problems, one of them was the trans temp sensor. So at least this confirms the reason for LHM.

 

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 Post subject: Re: Limp home mode / low voltage?
Posted: Sun Jul 04, 2010 12:05 am 
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Vic wrote:
Amongst a bunch of other error codes for other problems, one of them was the trans temp sensor. So at least this confirms the reason for LHM.
Most likely if you're sure none of the other codes are related.
Might be an idea to simulate trans temp with a resistor - pop it's pins out of the transmission plug - hook up the resistor, work your way up to the TCM.
All the info you need is at ecu-fuel-system-eec-f21/5-0-ecu-options-manual-conversion-discussion-t48222.html

 

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