02 VDC H6 with 4 trans codes and an engine code

[idosubaru]

2002 H6 VDC - runs and drives - been one of our main daily drivers for many years.

When first started it will surge and hunt for a gear like once or twice. Only when first started for about 10 seconds or less. After that it drives fine, no issues.

Today it almost stalled at a redlight - first time it's ever had much of a symptom beyond the first 10 seconds.  But no surging/hunting i don't think.

 

As far as I know all these codes came about at the same time recently:

 

P0335 - crank sensor. 

 

There are 4 transmission codes, 3 incorrect gear ratio codes and torque converter clutch circuit performance. 

P0741, P0732, P0733, P0734

 

I'm thinking one of those is causing the rest or there's damage to a wiring harness somewhere:

 

A google search finds no instances of a crank sensor causing transmissions codes on Subaru - but seems like it could be possible - does the TCM see the crank sensor?

 

I repaired one wiring harness under the passengers side carpeting due to rodent damage.....maybe there's more somewhere else (we seem to get a lot of rodents in the car now that we have 3 kids and crumbs everywhere)

 

Is there an easy way to check continuity of those P07xx codes?  

 

 

[CNY_Dave]

Almost has to be a power or ground issue with that scattering of codes!

 

Probably connectors or harness that go right into the trans.

[Fairtax4me]

If the torque converter is staying in lock-up, that could cause all of those codes to set. The lock-up solenoid may be failing. 

That will certainly cause your near stall wen coming to a stop, because the torque converter is locked and acting like a clutch in a manual trans. 

The converter staying locked could also cause the trans to stick in a higher gear as you slow down, so even though the TCU commands the trans to downshift, it can't because it's mechanically bound. Setting your incorrect ratio codes for 4,3,2. 

the crank sensor code could be set by the erratic stumbling that happened as the engine nearly stalled, then revved back up. The ECU may have seen that as a failed signal from the crank sensor and set the code. 

 

I would not expect a failing crank sensor to affect transmission shifting. The trans uses engine speed information, but doesn't get it directly from the crank sensor. It likely uses an input shaft speed sensor and the ignition control signal (tachometer) to determine engine speed.  

[idosubaru]

Thanks guys!

 

I would need to wait for the code to be set permanently to check continuity and resistance right?

 

I clear them and they don't return right away so it seems like they may test fine?

 

When I clear the codes they take a day to come back. Just like fairtax guessed, A trans code or two, no crank code last two times.

 

Can I monitor that torque converter solenoid somehow?

[Fairtax4me]

Maybe with a high end scanner or SSM.

Does the converter code come back every time? Could be a wire issue. If the solenoid circuit is being grounded between the solenoid and TCU that would keep the solenoid energized.

[idosubaru]

I think just a gear ratio code came back today but I could be wrong, I'll check for sure next time it lights up.

 

I changed the ATF screw on filter tonight for kicks.

[idosubaru]

P0733 & P0734 two days ago.

300 mile trip yesterday and nothing then or today.

 

Getting excellent gas mileage, same as ever.

 

What do these gear speed codes mean?

[idosubaru]

If the torque converter is staying in lock-up, that could cause all of those codes to set. The lock-up solenoid may be failing.

That will certainly cause your near stall wen coming to a stop, because the torque.

Okay it seems like you're probably right leaning toward the torque converter...

 

A couple times it'll make a rather loud whirring sort of noise up front - normally think it's a bearing or something. It'll be loud in park - then seems to go away in reverse, and drive or diminsh. And I think it goes away once the car is warmed up. (it's driving fine - i've taken some few hundred mile road trips and no issues and don't seem to be getting worse).

 

Can the TC make noise?

 

Would that most likely be the TC itself failing or a solenoid operating/related to the TC?

 

I just scrapped my spare TC for this trans of course. LOL

Edited June 20, 2016 by grossgary

[idosubaru]

I forgot one symptom - car will drift back a little bit if on a hill at a stop light before it goes forward. 

 

Complete symptoms: 

 

Torque converter clutch circuit OBDII code - reset and it'll come back. 

Sometimes noisy in the front - particularly at start up in Park/Neutral. 

Ocassionally (rarely) stall at a red light

Car will drift backwards a little bit on a hill from a stop before going forward.

 

Otherwise it drives great, never any suddering or issues and i've done some hundreds of mile trips in it. 

 

 

Is this mechanical TC failure or an electrical/solenoid failure - something controlling pressure/input to the TC?

[idosubaru]

History:

This transmission had a damaged pan which damaged a few solenoid connectors 45,000 miles ago.  I replaced the pan and replaced the connectors.  Are any of the solenoids/wiring under the pan related to the Torque Converter?

[Fairtax4me]

I swear I replied to this a couple days ago. Must be goin crazy. I've been working 10-12 hour days for the last 6 weeks or so. Need to get some r+r.

 

There is a solenoid in the valve body that controls the torque converter lockup. Since there is a code for that, I would expect to find either the solenoid, or wiring to it, damaged.

 

The converter lockup is basically a clutch ring around the outer circumference of the converter. It's inside the converter and not serviceable.

 

There are a few bearings in the converter which could cause problems, but I'm not sure they would cause your noise on startup. Normally when a converter bearing goes bad you get very little warning, a couple funny rattles maybe, and then the converter grenades internally.

 

How long does the noise last? Is it a loud whirr like a cat?

Does it happen immediately at startup, or start after maybe 1-2 seconds?

 

I usually consider a little bit of roll-back on a hill normal, but it depends how steep the hill is. The Outback converters usually have a higher stall speed, which decreases the amount of torque transferred to the drivetrain at idle, but it increases torque multiplication when you give it throttle, because the converter allows the engine to spin up to a slightly higher speed before it starts transferring power.

[idosubaru]

Thanks fairtax and man sorry bout those hours !

 

Since this had a gouged pan and damaged solenoids I repaired 45000 miles ago I'll see if I can find out which solenoid is for TC and see if I can test it with a multimeter.