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Check Engine / Intermitent AT Temp Light


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10 replies to this topic

#1 MTX sub

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Posted 21 March 2004 - 12:11 PM

Well I have seen Threads on CEL, but my situation is different in that occasionally the AT Temp light of my 2000 Outback with 100,00 miles goes on and the transmission begins to have very rough shifts.
The Check Engine Light came on Thursday and then later in the day the AT Temp light illuminated. Stopped and turned off the engine and the CEL stayed on but AT Temp light went off.

Drove car and it acted fine. Pulled up to the curb to let my wife drop something off at work and the engine died. As it sputtered it was like the I left the clutch in on a manual. I did notice that the AT Temp light flickered before the engine stalled. Started the car up and all lights were out no CEL no AT Temp!?!? Car drove fine home.

Next morning start up the car and the AT Temp light is blinking and the car was just started! CEL is on too! Put it in reverse and PLUGH! Engine stalls just like the torque converter is locked up and it acts like the clutch is in.

Restart the car, no AT Temp, but CEL on. Transmission shifts strange. Stop driving and use another car to get to work. Come back after work and CEL is on.

If AT Temp light is on when I start it seems that this is a faulty something or other because thier is no way in 50 degree temp that the car can start up with over heated fluid. Sounds similar to the BPT problem of CEL Code PO400 but the AT Temp has me worried.
Any Ideas?

#2 Cougar

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Posted 21 March 2004 - 12:55 PM

I would start by checking for a problem with temperature sensor or the wiring to it. Also check the wiring to the transmission control unit.

Here is a link that talks about the code you mentioned.

http://www.alldata.c.../20040301a.html

#3 MTX sub

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Posted 21 March 2004 - 02:29 PM

Drove to church .5 miles and CEL was on. It sat in the parking lot for 1 1/2 hours. Started it up and no lights. Drove fine both times. Can someone give me more information on the Back Pressure Transducer? Do 2000 have them? Where is it located? Just what does it do? In a previous thread a CEL light problem in a 97 Outback produced similar transmission dificulties, but they did not report any AT Oil Temp light illumination. Did 97 Outbacks have the AT Temp light?

#4 MTX sub

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Posted 22 March 2004 - 09:52 PM

Well dealer wants 75 bucks just to pull the codes and diagnose. The 98's and newer do not use the BPT so that is for sure not my problem.
My dad has even had trouble with strange shifting every once in awhile. Has anyone heard why? Bad tranny? I have heard that some people have had transmission replacements under warrenty. What was faulty?

#5 Cougar

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Posted 22 March 2004 - 10:28 PM

You should be able to go to an Autozone and they do a scan check for free I believe. You should also check out the AT temperature sensor and it's wiring. It may be the cause of all of this.

#6 friendly_jacek

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Posted 25 March 2004 - 10:49 AM

MTX,

I can bet $10,000 your codes are p0122 and TCM31. Faulty TPS, effects both engine and AT management. Please use palpay to email me $50 for "remote" OBD2 scan.

But seriously, I had the same problem in my 2000 sub with 45000 miles.
Note that AT temp light was blinking only. That means AT detected problem and went in limp mode (with hard shifts, etc). Only solid AT temp means overheating. There ia actually a procedure for pulling AT error code without scan, see below.

Now is the bad news.
I was charged $330 for replacement of TPS by dealer. $240 for a simple potentiometer, bloody murder! I was actually surprised that this was not covered by powertain warranty. The replacement took care of the problem but for a couple months only and it sometimes comes back in an intermitten fasion. I am afraid they replaced perfectly good sensor and the problem is with connection or wiring. Now I am wiser and invested $88
in OBD2 interface. The TPS is OK but O2 sensor has weird readings, sometimes it works, but often a flatline 0.5-0.7 V. I guess I will replace it. I do not know if TPS and O2 problems are related.

Below is what I found on one of the internet forums, it works for 2000 legacy:
"In any event, the flashing AT Oil Temp light indicates that the Transmission Control Module (TCM) has detected a problem and is trying to tell you about it. Here's the procedure for interrogating the TCM (...). It's one of those secret handshake procedures reminiscent of the pre-OBD ECU days. I swear I'm not making this up.

1) Warm up the engine
2) Turn the ignition switch OFF
3) Turn the ignition switch ON
4) Start the engine
5) Drive the vehicle at speeds greater than 12 MPH
6) Stop the vehicle
7) Depress the brake pedal and move the gear selector to "1"
8) Turn the ignition switch to OFF
9) Turn the ignition switch to ON
10) Move the gear selector to "2"
11) Move the gear selector to "1"
12) Move the gear selector to "2"
13) Move the gear selector to "3"
14) Move the gear selector to "D"

Now examine the AT Oil Temp light again:

If the light's blinking 4 times a second, then the problem is most likely a power supply or ground problem.

If the light's blinking 2 times a second, then the TCM believes all is normal.

If the light's on solid or not on at all, then there's a problem with the light's circuit.

If the light's blinking with one or more long (1.2 sec) pulses, followed by one or more short (.2 sec) pulses followed by a 1.5 sec pause, then you're seeing a TCM diagnostic trouble code (DTC). The long pulses indicate "tens" and the short ones indicate "ones" so you add up the number of long pulses to get the left digit of the DTC and you add up the number of short pulses to get the right digit of the DTC. DTCs are two digits long (e.g. 23, 36, etc.). The end of the "ones" is indicated by a 1.5 second pause. Then, if that is the only DTC stored, it begins repeating that DTC with the "tens" again. However, there may be more than just one DTC stored, in which case they are spit out sequentially with 1.5 sec pauses between them, until the whole sequence repeats again."

#7 friendly_jacek

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Posted 26 March 2004 - 10:07 AM

MTX,
where is my $50 for diagnostic work?
;-)

#8 mday

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Posted 07 April 2005 - 10:10 PM

Hi, I am a new user and did my homework by searching for a previous post about a car identical to mine with the identical problem: for about the past year, my 2000 Outback with 48,000 to 57,000 miles on it has very occasionally had the AT and CEL come on flashing and gone into what some have called "limp" mode with very hard shifting. I let it rest and it's usually fine. The dealer, of course, said no codes were readable and laughed at my request to have it consdered under warranty, since, as far as he knew (he rode in the car for 25 stop-and-go-miles and of course the problem would not recur) the car had no problem. Have there been any updates on this problem, and, beyond trying to read cryptic codes, can someone give me straight advice on what to do to fix the problem?

Thanks!

Michael

MTX,

I can bet $10,000 your codes are p0122 and TCM31. Faulty TPS, effects both engine and AT management. Please use palpay to email me $50 for "remote" OBD2 scan.

But seriously, I had the same problem in my 2000 sub with 45000 miles.
Note that AT temp light was blinking only. That means AT detected problem and went in limp mode (with hard shifts, etc). Only solid AT temp means overheating. There ia actually a procedure for pulling AT error code without scan, see below.

Now is the bad news.
I was charged $330 for replacement of TPS by dealer. $240 for a simple potentiometer, bloody murder! I was actually surprised that this was not covered by powertain warranty. The replacement took care of the problem but for a couple months only and it sometimes comes back in an intermitten fasion. I am afraid they replaced perfectly good sensor and the problem is with connection or wiring. Now I am wiser and invested $88
in OBD2 interface. The TPS is OK but O2 sensor has weird readings, sometimes it works, but often a flatline 0.5-0.7 V. I guess I will replace it. I do not know if TPS and O2 problems are related.

Below is what I found on one of the internet forums, it works for 2000 legacy:
"In any event, the flashing AT Oil Temp light indicates that the Transmission Control Module (TCM) has detected a problem and is trying to tell you about it. Here's the procedure for interrogating the TCM (...). It's one of those secret handshake procedures reminiscent of the pre-OBD ECU days. I swear I'm not making this up.

1) Warm up the engine
2) Turn the ignition switch OFF
3) Turn the ignition switch ON
4) Start the engine
5) Drive the vehicle at speeds greater than 12 MPH
6) Stop the vehicle
7) Depress the brake pedal and move the gear selector to "1"
8) Turn the ignition switch to OFF
9) Turn the ignition switch to ON
10) Move the gear selector to "2"
11) Move the gear selector to "1"
12) Move the gear selector to "2"
13) Move the gear selector to "3"
14) Move the gear selector to "D"

Now examine the AT Oil Temp light again:

If the light's blinking 4 times a second, then the problem is most likely a power supply or ground problem.

If the light's blinking 2 times a second, then the TCM believes all is normal.

If the light's on solid or not on at all, then there's a problem with the light's circuit.

If the light's blinking with one or more long (1.2 sec) pulses, followed by one or more short (.2 sec) pulses followed by a 1.5 sec pause, then you're seeing a TCM diagnostic trouble code (DTC). The long pulses indicate "tens" and the short ones indicate "ones" so you add up the number of long pulses to get the left digit of the DTC and you add up the number of short pulses to get the right digit of the DTC. DTCs are two digits long (e.g. 23, 36, etc.). The end of the "ones" is indicated by a 1.5 second pause. Then, if that is the only DTC stored, it begins repeating that DTC with the "tens" again. However, there may be more than just one DTC stored, in which case they are spit out sequentially with 1.5 sec pauses between them, until the whole sequence repeats again."



#9 friendly_jacek

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Posted 08 April 2005 - 02:40 PM

[...] beyond trying to read cryptic codes, can someone give me straight advice on what to do to fix the problem?


The only straight answer I can give you that you HAVE to read these "cryptic" codes and diagnose the problem before attempting to fix anything. Good luck!

#10 mday

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Posted 09 April 2005 - 07:07 PM

Hi again,

Yes, you were right. The TCM is flashing out 3 longs and a short, the 31 error code for a faulty TCM, right? And the TCM is listed as covered in the powertrain warranty. Although it's out of warranty now (over 5 years since purchase), since I first took the car to the dealer within the warranty period, would it not be fair for me to request that they replace the TCM at no cost? I have a feeling that the dealer will say no, but I believe that I then have a case to take to SOA if they do say no.

Do you know of any statistics on the frequency of occurence of this problem?

Thanks,

Michael

The only straight answer I can give you that you HAVE to read these "cryptic" codes and diagnose the problem before attempting to fix anything. Good luck!



#11 friendly_jacek

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Posted 10 April 2005 - 08:38 AM

Go ahead and reread my post. I said that 31 was a code for TPS. TPS is not covered by powetrain nor emission warranties. You on your own. The good news is it is v. easy to replace. Not cheap, though.




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