I just bought this car last night and on the way home the transmission went into limp mode. Auto zone game me these codes: P0700 & P0731. Searching around I found numerous people with this problem but there speedometer doesn't work and mine does, so I'm not sure if I have the same problem with the speed sensors or not.

Any help would be appreciated,

Thanks

Thomas

 

Oh sorry its a 98 concord

 

Typically the Input Speed sensor will set this code.
Speedo works off the Output Speed Sensor.
Recommend replaceing Input Speed Sensor

 

Ok, well I changed the output sensor no change so I will try the input sensor and see what happens

 

I had them check the codes again when I went back to get the input speed sensor and at first only P0141 came up which is the o2 sensor. Then I turned the engine on and put it into drive and a whole bunch of codes came up.
Listed below:
Po755 shift solenoid B
P0760 shift solenoid C
P1782 pressure switch
P1784 pressure switch circuit LR
as well as the previous codes P0700 & P0731

The transmission is stuck in second gear if that helps.

I would appreciate any more help on this compounding issue,
Thanks

Thomas

 

O would still do the input speed sensor first. The sensor compares input to ouput speeds that are used to calculate shift points.
The other codes point to the shift solenoid assembly but usually are not a problem in 98-01 cars. Sensors are notorious 98-01, solenoids 02 and up.

 

Changed both the output and input still no change. I'm starting to wonder if its the wiring. Some of it has electrical tape on it maybe there's a short.

 

Could the problem be that its stuck in second gear? When I shift from park to drive it goes right into second and won't shift from that. There was some shavings on the output speed sensor too. The transmission fluid is clear and full.

I'm just not sure what to think.

 

OK, so here's an update.

I replaced the solenoid/pressure switch pack, filter and fluid.

No change for the better. Now my speedometer jumps around like its a tachometer. also the dash gear indicator thinks its in Drive when I start the engine. and when I shift into any other gear, it boxes all the gears on the indicator and signals a check engine light. I started it in Neutral and quickly dropped it into drive which seemed to fix this problem, but after a few starts it went back to the same issue. My research says its the range sensor, but I decided to change out the TCM, which from my understanding, could be sending out false codes.

Bought a used 98 TCM from a used auto parts store, which should be here tomorrow. I hope that fixes the problem and I can get my car out of Limp Mode.

From what I understand, I shouldn't have to have the new TCM programmed for a 98-02 Concorde, but I need to turn the car on for 10 minutes and off then back on for another 10 mins; like 4 times so that it can communicate with other devices or what not.

Any info on that from anyone would be appreciated.

Thanks,
Thomas

 

OK, before I installed the new TCM I took my car to an automatic transmission shop who did a diagnostic on it and found these codes:

P0755 2-4 solenoid
P0705 Transmission range sensor
P0731 Gear ratio error in 1st
P1790 Fault after a shift

The guy said that he also checked the clutches for each gear which all were in good range:

LR 32
OD 103
2-4 49
UD 38

The guy's first words were "I think you are going to need an electrician before you need me".

After his recommendation to change the TCM I installed the one I purchased which had only one update version newer than mine. Mine was 081AJ new one was 081AK.

No change other than now my speedometer works again but still in limp mode and my dash indicator still thinks its in Drive when I start it in Park then highlights all gears.

I've just about changed everything electrical on this transmission and still nothing better than what I started with.

Even worse while I was letting my car run at idle it over heated. Come to find out that my fans don't turn on and all the fuses and both relays are good.

Looking at the wiring schematics it looks like the PCM receives signals from the speed sensors and other sensors which is supposed to turn on the relays at specific temperatures... hmm... I had already changed both the speed sensors so... Now I'm wondering if the new TCM is speaking a different language than the rest of my system and can't communicate, because of this update.

So just to list all that I've changed and checked:

Input & output speed sensors
Solenoid pack
Filter
Fluid
TCM
TCM shutoff relay & fuse
Battery (Because someone tried to use a positive post clamp on the negative post and when they realized it didn't fit they used a soda can tab in between to make it tight enough to clamp it down. How retarded is that, because we all know aluminum is such a great conductor!)

Tomorrow I'm going to Run some grounds from the negative post straight to the TCM housing, to the alternator, to the transmission, and check all other ground straps.

If that doesn't work I'm going to finally give in and take my car to an auto electric specialist.

BTW, I would actually appreciate some help. I don't mean to sound ungrateful, but one junior member giving me some shoot from the hip advice is hardly worth it.