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Request: How to reset TCU in 1996 Impreza


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Greetings,

 

I have just bought a 1996 Impreza HX-20S and have learnt that the flashing POWER light at startup means that an issue has been detected. It flashes 16 times in 4 seconds after ignition and then goes out. I don't know how long ago the fault occurred and would like to reset the TCU to see if it occurs again. I've read elsewhere that the TCU can be reset by pulling fuse 14 for 10 minutes, but the car is a Japanese import, so the fuse labels are all in Japanese. I've tried pulling a number of fuses that could reasonably be "number 14", but that doesn't appear to have reset the TCU as the POWER light still flashes as described above. To be clear: the light doesn't flash while I am driving the car.

 

The car is a right-hand drive, non-turbo 2.0 litre, automatic with AWD.

 

I really like my new Subaru and hope that there isn't anything seriously wrong. Any advice or help would be gratefully received, thank you.

 

Chris

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flashing at start up is a sign of a current TCU issue. you need to pull the code to find out why it's flashing. when you fix the problem the flashing will go away.

 

Thanks. Are there any instructions available online for getting the code (I found some for a Legacy that might work - will try on the weekend) or do I need to go to a dealer with the right gear?

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Does it have a "manual" button?

 

I don't recall how to pull the TCU codes on a an auto that doesn't have the manual button, but if you do have a manual button, you can try the instructions on my site. Go to notes & tips, trans related.

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Does it have a "manual" button?

 

I don't recall how to pull the TCU codes on a an auto that doesn't have the manual button, but if you do have a manual button, you can try the instructions on my site. Go to notes & tips, trans related.

 

Your instructions worked for me, thanks. The Impreza has a "Snow Hold" switch, which I used in placed of the "Manual" button in the instructions.

 

To other Impreza owners: There is also a shift lock button near the base of the shifter that can be pressed to allow the shifter to moved out of P when the engine is off so that the various steps in the instructions can be performed.

 

My error code is 24, indicating a problem with Duty Solenoid C. This seems to be rather common, based on what I've read here. There is certainly binding when turning slowly at full lock, but I haven't noticed it under other conditions (but then I've only just got the car, so it's all new to me).

 

I'm going to check the tyre pressures (there are four near-new tyres of the same type) and then investigate the wiring.

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Yeah, check tire pressures, also, you may want to change trans fluid.

 

Lastly, put a fuse in the FWD fuse holder and see if the binding goes away. If it doesn't, then it's most likely the duty c solenoid, and will need to be replaced.

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Yeah, check tire pressures, also, you may want to change trans fluid.

 

Lastly, put a fuse in the FWD fuse holder and see if the binding goes away. If it doesn't, then it's most likely the duty c solenoid, and will need to be replaced.

 

Adjusting the tire pressure made no difference. I will be changing the transmission fluid soon.

 

I've been working through the forum postings here (lots of great info, thanks) and tried inserting the FWD fuse. This also made no difference - the binding is still there and the FWD light does not come on on the dashboard. This suggests the wiring or solenoid is at fault, so I'll be checking them out next, using information found here:

http://www.ultimatesubaru.org/forum/attachment.php?attachmentid=1335

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  • 3 weeks later...

Just to wrap this up in case anyone else is looking through postings trying to get information, as I did:

 

My testing showed that Duty Solenoid C was open circuit and so either that or the wiring to it was dead. I took the car to a Subaru specialist (he was on Possum Bourne's team, which will mean something to some of you), who confirmed the diagnosis, pulled the transmission extension housing apart and found that the solenoid was indeed dead. He put a new solenoid in and changed the transmission fluid and now the car runs sweetly.

 

He said that it is common for these solenoids to fail, but that he hasn't seen any repeat failures if the car is maintained properly afterwards. This would include changing the transmission fluid per the maintenance schedule, keeping tyres at the recommended pressures (note the high pressure required by a space saver spare), and rotating the tyres to promote even wear (see postings on tyre circumference here).

 

Thanks again to everyone who has posted on this topic here. Although I couldn't fix the problem myself, it was still satisfying to identify it correctly and learn about the car in the process.

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Quick question. Do you have a "manual" button and a "snow hold" button on the shifter, or is the US button simply called "snow hold" in Australia? Neat either way. Take care,

 

Kevin

 

There's just one button: "Snow Hold". It is actually labelled like this:

 

*

HOLD

AT

 

The * is a snowflake symbol. To anyone who's wondering what the button/switch does, "AT" lets the car's automatic transmission use the normal range of gears and so is the regular setting for the switch, while "Snow Hold" prevents the transmission from using the lowest gear ("1"). In "Snow Hold" mode, the car will start off in 2 to reduce the chances of spinning the wheels.

 

The car is Japanese - here in New Zealand we import thousands of used cars from Japan each year.

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There's just one button: "Snow Hold". It is actually labelled like this:

 

*

HOLD

AT

 

The * is a snowflake symbol. To anyone who's wondering what the button/switch does, "AT" lets the car's automatic transmission use the normal range of gears and so is the regular setting for the switch, while "Snow Hold" prevents the transmission from using the lowest gear ("1"). In "Snow Hold" mode, the car will start off in 2 to reduce the chances of spinning the wheels.

 

The car is Japanese - here in New Zealand we import thousands of used cars from Japan each year.

 

This is the same as the "Hold" button on the first gen legacies.

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  • 11 years later...

16 2-4 brake duty solenoid. Short or disconnection in solenoid driving circuit 

 

Check the transmission pan for damage or replacement.  The pan is extremely close to the solenoids and the solenoids will crack if it's damaged/dented. 

If the pan is currently damaged - solenoid or wiring is probably damaged. 

If the pan looks like it's been replaced (look for new sealant or signs the bolts were removed) - maybe it was previously damaged, pan replaced but solenoids were not eventhough it was damaged. 

if you're in there - check the other solenoids, partiuclarly those in the same area. 

 

here is it's location just inside the transmission pan:

http://ww2.justanswer.com/uploads/baddad1/2011-08-05_130203_capture.png

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