Astra 2001 8v auto - Various fault codes | Technical matters | Back Room Forum

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Sat 1 Jan 2011 18:22

Astra 2001 8v auto - Various fault codes - markandchrissie

2001 astra 8v automatic, z16se engine.

The radiator fan failed to cut in while in traffic recently, and despite turning the engine off to try keep it cool it burst a hose.

Once cooled down the hose was fixed and coolant replaced. The car then drove home without problem for about 60 miles.

The next day, all was well except the eml was lit for a while but then went out.

The day following, the eml was constantly lit and the car hard to start. Once started it ran ok but was stuck in 3rd gear (automatic gearbox).

Fault codes present:
u2103 (engine control module malfunction)
u2106 (engine control module to transmission control module malfunction)
p0700 (transmission control malfunction)
p1700 (transmission control module service request)

There was also a p1540 fault logged (aircon pressure sensor) which is probably the reason for the fan not cutting in but a seperate issue.

Seeing that the ecu is bolted to the engine (bad design!) is this likely to have been damaged? I was replaced about 3 years ago although not sure of the reason. All sensor connections etc have been checked .

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Sat 1 Jan 2011 19:28

Astra 2001 8v auto - Various fault codes - Collos25

I do not think that the fan not working should be discounted,your original problem started because it was to hot and the fan not starting.If it was low on water or had an air lock and the temp sensor was in air and not water it would not work.The auto transmission got to hot because the cooler is probably in the radiator this was overheating causing a hose to blow.My conclusion is that the head gasget is leaking or it was so low on water it caused an air lock with your following problems .The gearbox fault codes can be caused by an overheating autobox.

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Sat 1 Jan 2011 19:29

Astra 2001 8v auto - Various fault codes - Collos25

Edited by Andy Bairsto on 01/01/2011 at 19:31

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Sat 1 Jan 2011 21:47

Astra 2001 8v auto - Various fault codes - markandchrissie

The reason it overheated wasn't due to it being low on water, just the fact it was in crawling traffic, where any car will start getting hot and boil over if the fan doesn't cut in.

I was due to fit a new cooling control module behind the front bumper as these often fail causing the fan to stop working.

Edited by markandchrissie on 01/01/2011 at 21:50

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Sun 2 Jan 2011 10:43

Astra 2001 8v auto - Various fault codes - Collos25

If you are in the UK it should never have overheated its to cold even in traffic the fan should not have come on,the car will get rid of its excess heat through the fan for the heater matrix.Perhaps the car also needs a new radiator or the stat is jammed it certainly needs a good coat of looking at.

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Sun 2 Jan 2011 13:36

Astra 2001 8v auto - Various fault codes - markandchrissie

With the exception of diesels which run cooler, most petrol cars left idling will overheat in time if the fan doesn't cut in. This is due to minimal coolant circulation at low revs, and no airflow to the front of the radiator. True, putting the heater blower on full will reduce the temperature slightly.

The question I really want answered is what is likely to cause the fault codes logged.

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Sun 2 Jan 2011 14:54

Astra 2001 8v auto - Various fault codes - Collos25

If the gearbox fluid overheated because the cooler is in the radiator then you will get these codes as I have said before.In the temps you have in the UK a cooling fan should never come on.

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Sun 2 Jan 2011 16:14

Astra 2001 8v auto - Various fault codes - markandchrissie

We'll have to agree to disagree about the fan never being needed. The many cars I've run over the last 20 years have always had the fans come in while crawling in traffic, whatever the outside temperature.

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Sun 2 Jan 2011 16:48

Astra 2001 8v auto - Various fault codes - elekie&a/c doctor

The cooling fan system needs to be in working order not only for engine coolant but also for the a/con condensor cooling.An engine overheat situation need not bring on the eml light.The P codes are powertrain dtcs (engine & gearbox).The U codes are network codes relating to transfer of info between engine and gearbox ecus.A faulty a/c pressure switch fault will not affect cooling fan operation.This could be a low gas pressure issue.In fact if you disconnect the a/c pressure switch ,the cooling fan(s) will run constantly in default mode.I would clear the fault codes,get the cooling fans fixed and retest the system.Could be an ecu fault,and as you have suggested,not uncommon.hth

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