***FIXED*** CEL - Incorrect Gear Ratios? Code P0731 etc.

[gtd65]

The other week I had the following four codes appear:

P0325/0304 Knock Sensor
P0731 A/T 1ST Gear Function
P0732 A/T 2ND Gear Function
P0733 A/T 3RD Gear Function

It was expected that the first code caused the last 3.....

Replaced the knock sensor and cleared the codes - all appeared to be well but the CEL came on the following day

Now when doing a scan the P0325/0304 Knock Sensor code is no longer stored but the gear ratio codes are still showing.

The car does seem to be reluctant to change up at times but once the car has warmed up it seems to be fairly consistent but not as smooth when changing (this is an auto box of course) as I'm used to.

What I've been doing as a work around is to rev the car then take my foot off the gas to allow the car to change up - seems to work most of the time - however, if I just keep the foot down it'll rev out before it changes...

Any ideas?

Solution!

Well, despite not having a TPS error code (or obvious TPS problems) - the TPS was showing readings well out of tolerance for the car.

Just changed the TPS today - which is the second TPS the car has had since owning the vehicle - and now the gears are changing perfectly!

It's taken a while to get to the bottom of this but it was a very cheap and easy fix now that it's over!

[rioredstang]

I don't know what model we are working on but I would check fuses first. Then test grounds for transmission. The solenoids share a common ground or power source.

[gtd65]

I don't know what model we are working on but I would check fuses first. Then test grounds for transmission. The solenoids share a common ground or power source.

This is a 1995 240SX SE with A/T. Completely standard.

[korrupt1]

forgive my ignorance here.....I have a 95 altima I just got and am experiencing the p0731,732,733 codes also....and what the heck is a TPS? if I can change that and fix this I would be much happier than replacing a entire transmission (while cheap enough, I just dont wanna do it if I dont have to)

the car is a
1995 altima GXE, 143,xxx on clock, runs and drives just fine other than it wont shift unless you let off throttle (as mentioned in earlier posts)......I went to autozone, had codes pulled and one guy says its a servo pack....but then another guy says it doesnt have that.....I swear autozone gets more and more confusing by the second.

I checked fluids and they appear clean (pinkish colored), I did not pull pan and look at filter but seeing as I bought from a autozone manager....and everything in car seemed to be filled and topped off good (no overheating issues either)....and he had a stack of receipts for replacement parts....I was gonna start looking into wiring and hope maybe a bad ground?? even though I havent done this work in forever.....start simple instead of going gungho into the worst possible....K.I.S.S. ya know?

anyways...TIA for the help...I been scouring thru online looking and this was one of the first that said got it fixed without dumping a transmission out.

am I correct in thinking TPS...Throttle Position Sensor? and where would that be located at on this car?

Jim

[gtd65]

forgive my ignorance here.....I have a 95 altima I just got and am experiencing the p0731,732,733 codes also....and what the heck is a TPS? if I can change that and fix this I would be much happier than replacing a entire transmission (while cheap enough, I just dont wanna do it if I dont have to)

the car is a
1995 altima GXE, 143,xxx on clock, runs and drives just fine other than it wont shift unless you let off throttle (as mentioned in earlier posts)......I went to autozone, had codes pulled and one guy says its a servo pack....but then another guy says it doesnt have that.....I swear autozone gets more and more confusing by the second.

I checked fluids and they appear clean (pinkish colored), I did not pull pan and look at filter but seeing as I bought from a autozone manager....and everything in car seemed to be filled and topped off good (no overheating issues either)....and he had a stack of receipts for replacement parts....I was gonna start looking into wiring and hope maybe a bad ground?? even though I havent done this work in forever.....start simple instead of going gungho into the worst possible....K.I.S.S. ya know?

anyways...TIA for the help...I been scouring thru online looking and this was one of the first that said got it fixed without dumping a transmission out.

am I correct in thinking TPS...Throttle Position Sensor? and where would that be located at on this car?

Jim

Hi Jim,
If you do a search for all of my posts you'll see a few threads releated to this problem which have further info and photos.

The TPS (Throttle Position Sensor) is located at the side of the "Throttle Body" and based on my experience here would certainly be the first thing to check and replace (if out of tolerance).

I got my replacement at the breakers yard for something like $6 if I remember correctly.

Here's the general location and procedure for the TPS check on the 240SX:

There's two parts - here's Part 1.

http://www.youtube.com/watch?v=V-Mwxicmpg4

The Altima uses a transverse engine (FWD) so, it'll be going left to right, as opposed to front to back (RWD) as shown with the 240SX.

Hopefully this will mainatin the K.I.S.S. principle

The same TPS is used in a variety of cars - mine was sourced from an Infiniti model - you can probably have a look at the cross references on eBay listings for the TPS to see the full list of cars that use the same sensor part number

[gtd65]

Here's the relevant threads to look at:

any-auto-trans-experts-here-s14-1995-24 ... 28774.html

1995-240sx-s14-auto-trans-shifting-prob ... 26199.html

TPS check thread - you can get a very cheap multi-meter at Harbor Freight Tools for $5 if you don't have one.

throttle-position-sensor-tps-check-t532434.html

Lots of info here but looking at my solution perhaps a departure from the K.I.S.S. principle for the 240SX convertible:

94-240-conv-with-at-shift-problems-t96505.html

[korrupt1]

Thanks man. I am a old school guy but always been imports...have had a variety of nissans (ranging from a pristine 81 200sx to a 240z (that loved to hate me for some reason) and shopping for a 510 (cuz they just cool) and a dropped 97 hardbody, also handful of hondas, Acura Legends, even tossed a Toyota Camry in there..I dont keep cars for very long because...well...I get bored. LOL

I went the expensive route and just ordered a new one which arrived same day and I just got it installed (I work some VERY weird hours...on call 24/7 but have a shift time that I am the only person on)......I hope this fixes my issue...I am really hoping to not drop a trans if I dont have to.

Got a degree in electronics engineering so wires dont scare me none....and enough tools to scare most people away.....all I really need is another house and a lift and lookout....I be looking to turn a altima into a awd, sr20 motored beast....and god forbod I get ahold of another welder. LMAO

Ill be checking out your threads...seeing as the motors were based the same for the 240 and the altima (almost bought a 240 with a LSD...but dude had some crazy way of starting it that basically...scared the crap outta me so I left...although once running....it did seem to run fine.

[korrupt1]

on the plus side I have manged to find several used trans here...all quoted to be in "excellent shape with T/C included" for anywhere from $200-300 dollars..........worst case scenario there though...trying to avoid this

[gtd65]

Thanks man. I am a old school guy but always been imports...have had a variety of nissans (ranging from a pristine 81 200sx to a 240z (that loved to hate me for some reason) and shopping for a 510 (cuz they just cool) and a dropped 97 hardbody, also handful of hondas, Acura Legends, even tossed a Toyota Camry in there..I dont keep cars for very long because...well...I get bored. LOL

I went the expensive route and just ordered a new one which arrived same day and I just got it installed (I work some VERY weird hours...on call 24/7 but have a shift time that I am the only person on)......I hope this fixes my issue...I am really hoping to not drop a trans if I dont have to.

Got a degree in electronics engineering so wires dont scare me none....and enough tools to scare most people away.....all I really need is another house and a lift and lookout....I be looking to turn a altima into a awd, sr20 motored beast....and god forbod I get ahold of another welder. LMAO

Ill be checking out your threads...seeing as the motors were based the same for the 240 and the altima (almost bought a 240 with a LSD...but dude had some crazy way of starting it that basically...scared the crap outta me so I left...although once running....it did seem to run fine.

It sounds more like I should have been asking YOU for advice

I'm an Engineer as well but I deal with the contractual side of things these days - mainly on Energy projects.

I'd love an old 240Z or even an early 260Z - need to get rid of those US spec bumpers though!

Right now I'm back in Scotland and the weather is crap due to a visit from Hurricane Irene but it's usually wet n miserable here anyway

Back over to Florida next month and hopefully this time I'll figure out the remote entry wiring....

Have another task as well - the GF has notified me that there is a gas/petrol leak from the car - might be a cracked (plastic) tank according to the information on the net...bummer.

[korrupt1]

alas.....the TPS was not my issue apparently....but I know for a fact I have a brand new one and the previous looks pretty new as well. Guess I am solenoid hunting.

Irene nailed you huh? I had some friends out the east way....they were....disappointed with the supposed fury of something that never happened....till I showed them pics from other parts where it tore things apart. I never expected it hit cat4 on land....that would basically wipe out the entire eastern coast....the news....as usual....overhyped. I expected it to be a cat 3 over water (as it did) and gain in power...and once coming into land dropping....(as it did).

I was in FL for the last really BIG ONE....my buddy and I turned razor scooters into a form of windpowered scooters....we took trash bags and attached some wood....voila'!!! windsails!! all was good till I lost mine at about 20 or so MPH....it hurt on landing and we decided hang it up and head inside...and like us Irish people do....we drank. LMAO

the hunt to repair the trans continues. I most likely will get a used, tear it down, rebuild it and stick that in or maybe I will just say forget it and go manual...although I prefer auto cuz I am lazy anymore and I only drive this car out of town and I only use it 4 days a month...otherwise it pretty much sits in its parking space and doesnt do much.

[gtd65]

Did you try disconnecting the relevant sensor to see if the car went into "limp home mode" which is basically only 2nd gear - but you can also manually select 1st gear too?

Just a quick check - you did get a TPS for an Auto box?

...The manual version is different.