15 replies to this topic

[dannal]

I swapped my beloved van for an '05 Liberty 2.5 auto a few months back.  It had the CEL light on and the cruise light was flashing and not operating.  The car drove fine though aside from the A/C and cruise not working.  Then randomly the CEL came on with more dash lights and the transmission stopped working properly.  It won't allow me to shift out of park sometimes and then only drives in 3rd gear or reverse.  After throwing a tantrum and delivering it to a mechanic he suggested it was the transmission ECU.  I finally tracked down an identical one (at great expense) and had it installed.  Some of the lights disappeared and it seemed to work for a few minutes but then developed similar issues such as dash lights, CEL and the driving in 3rd gear thing.

 

I am hoping someone out there is proficient in these types of issues as this 5k car is fast becoming a money pit.  Any help would be hugely appreciated.  I am at my wit's end with this so I apologise if I have not provided enough information or made a mess posting this.  Cheers! :-D

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[El_Freddo]

Start off by having the codes read. Once this is done you’ll have more of an idea of what the issue might be.

Also ceck that the fluid level is correct in the auto.

Find an independent mechanic that specialises in Subaru’s

All the best with it!

Cheers

Bennie

[duncanm]

9/10 auto trans problems are due to insufficient or dirty fluid.

The new ECU just found the same issues in the trans the old one had detected. 3rd gear sounds like a safe mode.

Not worried about the 'AT Oil Temp' light? That'd be my #1 concern!

[dannal]

Thanks so much for your replies folks.

 

The codes have been read and were extensive.  I'll dig out the paperwork sometime tomorrow and post the results.  However, it just seems really strange that it was working faultlessly and then all of a sudden it stopped working and showed all of these faults.  I find it very strange that so many errors happened all at the same time - this is why it was suggested that it was the trans ECU that was the issue.

 

The trans fluid level is ok but I'm not sure on the condition or age of it.

 

I have been asking around my area for a Subaru specialist but haven't had much luck yet and was giving my current mechanic a chance to fix it as he is honest bloke.  I don't want to take it to the dealer as I have never walked away from taking any previous vehicle to a dealer with a small bill lol.

[duncanm]

dannal,

agree with your assessment of dealers.

Have a chat to your mechanic.. did he check the pump? All the sensors connected to the TCU ok? - sounds like maybe a sensor has failed.

[dannal]

Have a chat to your mechanic.. did he check the pump? All the sensors connected to the TCU ok? - sounds like maybe a sensor has failed.

 

Pump?  Now I am really showing off my ignorance :-(  I believe the mechanic played around with the connections to check they were all ok.  Any idea what sensors?

 

Thanks.

[duncanm]

Pump?  Now I am really showing off my ignorance :-(  I believe the mechanic played around with the connections to check they were all ok.  Any idea what sensors?
 
Thanks.

sorry - I'm being an idiot and thinking of power steering. The only ATF I usually play with.

[El_Freddo]

I’m not an auto guy but I’m waiting for the list of codes. These will no doubt point you in the right direction. It could also be that the car had an auto box swap from another year model that’s not 100% compatible. Can you pull the trans code too? It should be on the bell housing somewhere. On manuals it’s near the starter motor on the passenger’s side of the bellhousing.

What “new car” maintenance have you done? Fluid flush and new filter in the trans?

Cheers

Bennie

[dannal]

sorry - I'm being an idiot and thinking of power steering. The only ATF I usually play with.

All good ;-)

[dannal]

I’m not an auto guy but I’m waiting for the list of codes. These will no doubt point you in the right direction. It could also be that the car had an auto box swap from another year model that’s not 100% compatible. Can you pull the trans code too? It should be on the bell housing somewhere. On manuals it’s near the starter motor on the passenger’s side of the bellhousing.

What “new car” maintenance have you done? Fluid flush and new filter in the trans?

Cheers

Bennie

I have attached a photo of the paperwork with the error codes on it.  I also realised we're in the same town lol.  The throttle position sensor is bad but I don't want to replace it yet.

 

I don't know if it has had a box swap - the problem I have with a lot of possible problems is that it was working faultlessly for weeks before it went from having 1 issue to several.

 

I haven't done any maintenance as I don't want to blow money on servicing a car if it's not economically viable to repair - I don't want to throw away good money after bad :-(

 

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[El_Freddo]

You’re in Benders? Which part? I’m in Flora Hill.

That’s a fair list of issues. Some things you could try out for cheap - and get to know your ride a bit better:

- check all fuses - under bonnet, somewhere near the driver’s feet (some are in the side kick panel, earlier models are above the driver’s feet on the rhs). There’s also usually a “2wd” fuse holder on the strut tower or firewall. This is usually used when towing on the rear wheels.

- One at a time, disconnect the plugs on the engine and the gearbox, check for corrosion in the plug connections. Spray some WD40 into the plug and clip it back together. If there is some corrosion present, try cleaning it up with a small knife (scrape the corrosion effected area). Make sure you disconnect the battery before doing this.

- “the battery dance” - disconnect the battery overnight. Connect it in the morning, start the car and let it idle until the coolant fans have cycled at least once. Don’t touch the throttle until after the fans have cycled. Check the check engine light to see if it’s illuminated - same for the rest of your warning lights. If ok, go for a drive and see what shows up. Check codes.

- get a digital factory service manual - learn how to read the codes without a code reader. There’s a set of plugs under/near the steering column for the engine ECU, plug these together, turn the ignition ON (engine off) and count the flashes from the check engine light. Long flashes = ten, short = one. So long, long, short, short, short is a code 23. If there are several codes the light will flash each code onenafter thenother then loop back to the first one. If no stored codes, it will flash its model designation in a loop. This is also documented in code lists. Hopefully you’ll be able to manually (and very cheaply) read the transmission control unit (TCU) codes too. This is helpful when you swap out one sensor then check to see if anything has changed before going for the next unit.

You might find that one sensor’s operation effects other sensors that may throw them out of normal operation, thus multiple codes. Your throttle position sensor could also effect the TCU and its sensors.

Cheers

Bennie

[dannal]

You’re in Benders? Which part? I’m in Flora Hill.

That’s a fair list of issues. Some things you could try out for cheap - and get to know your ride a bit better:

- check all fuses - under bonnet, somewhere near the driver’s feet (some are in the side kick panel, earlier models are above the driver’s feet on the rhs). There’s also usually a “2wd” fuse holder on the strut tower or firewall. This is usually used when towing on the rear wheels.

- One at a time, disconnect the plugs on the engine and the gearbox, check for corrosion in the plug connections. Spray some WD40 into the plug and clip it back together. If there is some corrosion present, try cleaning it up with a small knife (scrape the corrosion effected area). Make sure you disconnect the battery before doing this.

- “the battery dance” - disconnect the battery overnight. Connect it in the morning, start the car and let it idle until the coolant fans have cycled at least once. Don’t touch the throttle until after the fans have cycled. Check the check engine light to see if it’s illuminated - same for the rest of your warning lights. If ok, go for a drive and see what shows up. Check codes.

- get a digital factory service manual - learn how to read the codes without a code reader. There’s a set of plugs under/near the steering column for the engine ECU, plug these together, turn the ignition ON (engine off) and count the flashes from the check engine light. Long flashes = ten, short = one. So long, long, short, short, short is a code 23. If there are several codes the light will flash each code onenafter thenother then loop back to the first one. If no stored codes, it will flash its model designation in a loop. This is also documented in code lists. Hopefully you’ll be able to manually (and very cheaply) read the transmission control unit (TCU) codes too. This is helpful when you swap out one sensor then check to see if anything has changed before going for the next unit.

You might find that one sensor’s operation effects other sensors that may throw them out of normal operation, thus multiple codes. Your throttle position sensor could also effect the TCU and its sensors.

Cheers

Bennie

Yes mate, Epsom/Huntly here.

 

I apologise again for my lack of info.  I have been dealing with this car for so long whilst juggling 5 kids and the rest of life lol.

 

I checked all of the fuses manually beside the steering column and near the strut tower but I don't know how comprehensively.  I removed each fuse, checked it for continuity and then replaced it.  Everything "looked" ok and not a single fuse failed so I had ruled that out.

 

I did disconnect the battery several times for several days before starting and running but there wasn't any change.

 

The mechanic has scanned the ECU and TCU several times for codes as well as resetting them but they have returned.

 

I was told by a transmission specialist that when these transmissions go they never go this bad.  You might get 1 or 2 codes but never most of them lol.  It's so frustrating because it was running faultlessly one minute and then like this the next.

 

Thanks again for your help Bennie

[duncanm]

Is the ECU CAN Comms failure (P0600) a clue?

 

Maybe the failure is ECU/TCU communication, and its not the trans at all.  Not sure if they use CAN from ECU to TCU.

 

It might be worth checking ECU wiring and plugs are all ok.  Think all Sub's are in the passenger footwell under the carpet. Pull it and give all the plugs a good clean and inspection.

 

Do you know the history of the car ?

[dannal]

Is the ECU CAN Comms failure (P0600) a clue?

 

Maybe the failure is ECU/TCU communication, and its not the trans at all.  Not sure if they use CAN from ECU to TCU.

 

It might be worth checking ECU wiring and plugs are all ok.  Think all Sub's are in the passenger footwell under the carpet. Pull it and give all the plugs a good clean and inspection.

 

Do you know the history of the car ?

I will have to wait to get the car back from the mechanic next week before I can check those connections.  I have checked the wiring and plugs on top of the trans under the bonnet and they appeared to be ok.  I pulled them apart, gave them a good wiggle and deemed it good lol.

 

I don't know the history of the car but the bloke I got it from is a real piece of work.  I probably would have folded the goose in half in my angrier younger days :-p

[dannal]

Sorry, still waiting for my mechanic to be available to pick it up and bring home.

[dannal]

Alrighty then!!!  I have the Liberty back and here are the codes that continually show up:

p0743 - TORQUE CONVERTER CLUTCH CIRCUIT

p0758 - SHIFT SOLENOID B

p0753 - SHIFT SOLENOID A

p1707 - AT AWD SOLENOID VALVE CIRCUIT MALFUNCTION

p0763 - SHIFT SOLENOID C

p0768 - SHIFT SOLENOID D

 

As it stands now, I have replaced the TCU and have so far removed the CAN error so the ECU and TCU appears to be communicating correctly now.  I don't believe the transmission is faulty, I believe there is some type of electrical issue causing the transmission to enter limp mode and throw out all of these errors.  Some guy on the following forum https://forums.nasio...d.php?t=2801503 had similar error codes when he started messing around with the electrics.  The problem is that I haven't touched the car and wouldn't know where to start.