# 97 Altima Transmission codes advice?



## transit360 (Oct 9, 2011)

Greetings all, 

Newbie here. Thank you in advance of any suggestions you all may have. 

I'm looking to purchase a '97 Nissan Altima. Automatic. 197k. Previous owner says they were driving fine, then car went into limp mode and check engine light came on. I scanned the codes and got:
po755 - shift solenoid B malfunction
po720 - speed sensor malfunction
po740 - torque converter clutch circuit malfunction

Vehicle starts/runs fine, however takes off in higher gear and won't upshift/downshift (limp mode). Fluid level OK, but not sure how old it is. 

So I need guidance. Could any one of these codes trip another code? Are they related? Is this a sign of catastrophic failure? 

My first inclination is to drop the pan, check for debris, and change filter and replace with correct fluid and level. Is there anything else you all would do that I could check before dropping the pan? Testing the sensors? Any tricks?

I was expecting one code...but 3 codes being present kinda make me wonder if one tripped another, or if all 3 could be related to dirty fluid, or if it bulletized internally. Any suggestions are greatly appreciated. Thank you!


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## smj999smj (Jan 1, 2006)

P0740 and P0755 are both potential problems with the shift solenoids. The torque converter clutch circuit uses the speed sensor input for its operation. There was a recall (Campaign ID #8119) for the shift solenoid pack on 97 Altimas and Maximas, so the first thing I would do is check for any open campaigns and recalls for your Altima. Any Nissan dealer can look this up if you give them your VIN # or you can contact the Nissan customer service hotline at 1-800-NISSAN-1. If there are no open campaigns or recalls, check the harness going to the transmission solenoids for any shorting or rub-through against the transmission case.


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## transit360 (Oct 9, 2011)

That's a great suggestion about contacting the dealer about recalls on the shift solenoids, thank you! And the info about the TCC getting it's signal from the VSS is exactly what I was looking for too!
Yes, the thought occured to check the harness for rubbing/damage. I read that a pinhole-size hole can cause stuff to go screwy. Any guidance on tracing the harness? For instance, when I go to do this, where would I start and what should I look for?
I know that the speed sensor is bolted on using a single bolt on/near top of the trans. So I guess I could trace it from there. But any hints or suggestions are welcome. Thanks again.


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## smj999smj (Jan 1, 2006)

Just do a visual inspection of the transmission harness, simply looking for any places where it is chaffed or has rubbed through.


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