Transmission will not shift?

Good evening,

The first thing I would do is verify the battery is good. Low voltage will cause this issue. Make sure the battery load tests good and the cables are clean and tight.

https://www.2carpros.com/articles/automatic-transmission-problems

https://www.2carpros.com/articles/car-battery-load-test

Is the check engine light on?

When was the last time you changed the fluid?

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

Roy

i tried all these things. the battery is good, alternator charging normally, connections cleaned, transmission fluid-level fine, fluid viscosity good, fluid recently changed etc. check engine light not on and d4 not blinking. now the car is shifting fairly well when it is cold like in the morning then after seven to ten miles it will start down shifting and stay in second gear. a friend suggested it was the speed sensor but i haven't tried that yet and someone else said it could be the TCM. there is no plug-in for an obd anywhere. all fuses appear to be good. what should i do?

At this point, I would take it to a transmission shop and have them check it for you since you cannot determine the issue on your own.

Sounds like a valve body issue from here. If it were electronic, it would code.

Roy

When i start the car it runs fine but about 15 20 mins go by and it starts to down shift it will hold the rpms high but if i let off the gas or press it harder it will go up and down but the rpms r way off but the crazy thing is that if i disconnect the bat. then re connect it it works fine for about the same time until its warm

Hi jtate22153,

Is the D4 light showing and blinking when the problem occurs?

Symptoms indicates a possible fault with the TCM or its circuits.

no lights come on d4 does not blink

Get the Throttle Position Sensor checked. A voltage test would be able to determine if it is at fault.

Hello and thanks in advance for any and all help.
I have a 94 Honda Accord EX with 214000 miles on it. The car runs good, trans shifts smooth for about an hour or 30 to 40 miles of freeway driving. Then on the freeway the trans will downshift in to second gear and stay there, then the next day it starts all over again, runs fine until freeway for an hour. I have tried to test the TCM but get no blinking from the D4 light. The trans oil is a bit brown but no burnt smell at all. I changed the trans fluid with Honda ATF-Z1 trans fluid. I’m testing it now to see if that helps.
Any ideas what it could be and how to test for it?

Hi hondaguy202,

Seems the TCM is faulty and locking the shift solenoids.

When stuck in 2nd speed, does restarting the engine make any changes?

Did you try locating for fault codes without turning the engine off when it happened?

Restarting the engine has a temp fix for it ... the longer it sits the better it gets. No i have not tried getting codes from the TCM at the time of the downshift. Can you just jump the pins any time or will that hurt the system? The TCM was high on my list of what it could be, my though was that after an hour or so some of the IC in the TCM would malfunction and cause the unwanted downshift. Do you know of a way I can test to see if it is TCM/electronic parts or a hydraulic issue i.e. a blown seal for a plug screen or passage that is causing it to go into limp mode.
Thanks

Hi hondaguy202,

You can jump the SCS anytime without causing any harm whatsoever.

Seals, fluid pressure and clutches would not cause it to go into limp mode. Only electrical faults can.

The only way to test if it is the TCM is to substitute 1. You do not have any error codes so it is not possible to test if it is TCM, sensors or solenoids.

I jumped the 2P connector, swiched on the key and watched the D4 light, but it did do anything. Should the D4 light do something to let me know that it is in test mode?

The transmission will not shift. You can manually shift into 1st grear then shift into drive. Replaced Transmission, same problem. Replaced all 4 Shift Solenoids, same problem, Replaced Transmission computer ( three different times), same problem, Replaced both sensors, same problem. Now here is a different twist.... you can take the battery loose, wait about two minutes, reconect the cable. Now the transmission will operate like it should. It may take ten miles to fault out or it may take a hundred miles before it faults out. When the transmission faults the D4 lite will stay on until you disconnect the battery. Then can drive for a while OK.................

Any help?

Ok I found a better jumper and found so trouble codes
D4 code 15:Disconnected mainshaft speed sensor, shorted speed sensor or faulty speed sensor
Check engine code 22: VTEC Oil Pressure Switch
defective circuit or unplugged / defective oil pressure switch.
But I don't see how ether of those could cause the AT to downshift into second after an hour of freeway driving.
Thank you for all your input.

Hi CDs86Vette,

Thank you for the donation.

When the D4 light comes on, does it go off if you restart the engine?

Did you try to retrieve for trouble codes?

Since the TCM was replaced 3 times, the possibility of it being the cause is rather low, unless there are changes in the symptoms.

I would lean more towards a bad connection somewhere.

Test the Throttle Position Sensor to see if it is working within specs.

Hi hondaguy202,

The mainshaft sensor or its circuit might be working when it is cold and after some running it fails causing the TCM to go into limp mode. That is the reason it downshifts to 2nd speed. It could be a faulty TCM causing the circuit failure.

The VTEC malfunction should have nothing to do with the trans. It would affect the performance of the engine only. However engine performance would affect the shifting of the trans.

The D4 light will stay on until the computer is reset.

I have been unable to get any codes when the D4 light is on. I may be doing it wrong.

I have checked all the connections that I can find and they appear to be good.

Could the ECM be causing this problem?

With all that I have replaced or missed with the symptoms have not changed.

The D4 light staying ON till after resetting indicates a faulty TCM. If it is a wiring fault or any other problem, the D4 light would not come on after restarting. I might come on after some driving.

Did you bridge the SCS connector to retrieve the trouble code?
Were the replaced TCM of the correct P/N?
Were they rebuilt or used?
The ECM is linked to the TCM and could possibly be causing it if there is a fault with the power supply.

Check the ECM harness connectors for possible contaminations or loose contact.

when i drive down road full throttel the car wont shift into next gear,let up on gas an it will. it sounds like a rev limiter not letting it shift.you can also do this while in park rev up and starts popping like rev limiter is not letting you tac all the way..checked distributer plugs wires cat, converter fuel pump fuel filter changed trans fluid changed cdi box checked adj. cable from fuel injection to trans.what could it be....helpppppp

Hi rws68,

At what rpm does the engine cuts off when revving it?

How did you adjust the trans throttle pressure cable?

[quote:011fc93b37="KHLow2008"]Hi rws68,

At what rpm does the engine cuts off when revving it?

How did you adjust the trans throttle pressure cable?[/quote:011fc93b37]
4500-5000 red line at 6000
i adjusted all the way down and all the way up but did not see a change..thanks

Hi rws68,

Before the early cutting off happened, did you do any repairs/replacement of the throttle body, Throttle position sensor or ECM? A wrongly adjusted/faulty TPS would cause the problem.

The tran throttle pressure cable is to be adjusted to have exactly no free play and start moving the lever as soon as the accelerator throttle valve starts opening, ie the engine starts revving up.

[quote="KHLow2008"]Hi rws68,

Before the early cutting off happened, did you do any repairs/replacement of the throttle body, Throttle position sensor or ECM? A wrongly adjusted/faulty TPS would cause the problem.

The tran throttle pressure cable is to be adjusted to have exactly no free play and start moving the lever as soon as the accelerator throttle valve starts opening, ie the engine starts revving up.


hi KHLow2008,

bought the car as a spare and was not running.put a new spring in the distriuutor and fired right up..also someone said it may be temp sensor that it is telling the computer that the temp is at a certain degree????? would try but want to make certain tired of it nickle and dimeing me to death. also read the computer and flashed #6 it had flashed another code a while back but forgot which..thanks

Hi rws68,

I would not recommend changing anything until the part has been confirmed to be faulty.

DTC was stored but was the CEL showing?

DTC # 6 = Engine Coolant Temperature sensor.

Check the wires and connectors to see if they are properly installed.
Warm up engine to operating temperature, until cooling fans comes on and turn ignition switch off.
Disconnect ECT wire socket and measure the resistance across the 2 ECT terminals. Reading should be between 200 to 400 ohms and if not within range, ECT is faulty.

Btw, am curious about the spring in the distributor. I can't recall the distributor being equipped with any springs.

[quote:5b21e68992="KHLow2008"]Hi rws68,

I would not recommend changing anything until the part has been confirmed to be faulty.

DTC was stored but was the CEL showing?

DTC # 6 = Engine Coolant Temperature sensor.

Check the wires and connectors to see if they are properly installed.
Warm up engine to operating temperature, until cooling fans comes on and turn ignition switch off.
Disconnect ECT wire socket and measure the resistance across the 2 ECT terminals. Reading should be between 200 to 400 ohms and if not within range, ECT is faulty.

Btw, am curious about the spring in the distributor. I can't recall the distributor being equipped with any springs.[/quote:5b21e68992]

i checked the ect terminals and got nothing. i warmed up the car turned off and checked again and got nothing.the 2 fans come on as soon as i turn the switch on??? and the spring....there is a place in the distributor that i replaced a spring in it to get better conn. and it worked?? also the car will load up on gas and is hard to start up a little while after it has run awhile. i figured that the computer was telling it to give more fuel since the sensors were not reading right..any ideas..thanks wayne

i have a 1994 honda accord 2.2 liter automatic the transmission once it shifts to second i have no power even with the throttle to the floor very slow exceleration and passing gear will not kick in

Hi wayne,

Ok, I know what you mean by the spring, it is located at the tip of the ignition coil. If that helps, you need to check the ignition coil condition. It would cause the difficult starting if the sparks are weak. Check if the sparks are bluish and not orange.

ECT is located under the distributor on the cylinder head. Use ohmn meter to test. Test ECT resistance, not wire socket.

Hi there,

this will be an internal issue with the transmission, you will need to get this inspected by a transmission specialist as they will have the equipment to do all the diagnostic testing.

mark (mhpautos)

[quote:75151b502d="KHLow2008"]Hi wayne,

Ok, I know what you mean by the spring, it is located at the tip of the ignition coil. If that helps, you need to check the ignition coil condition. It would cause the difficult starting if the sparks are weak. Check if the sparks are bluish and not orange.

ECT is located under the distributor on the cylinder head. Use ohmn meter to test. Test ECT resistance, not wire socket.[/quote:75151b502d]

i didn't test the socket i had tested the 2 prongs on each of the ect. there was no reading cold or warmed up. and the fans come on as soon as you turn on the switch.as for the weak spark i understand what you mean but you can smell the rich smell of gas like it is getting too much. i pulled out in yard to clean and 2 hrs later it spit and sputtered like loaded up on gas...i drove it to work a couple of time and after 8 hrs of sitting it started up spitting and sputtering but always clears up in a couple of minutes.the car always starts up fine when is parked and started the next day..thanks

Hi wayne,

Too much fuel is being fed through the injectors and a faulty ECT can be the cause.

If the CEL keeps showing an ECT error, I would recommend replacing it first.

Transmission problem
1994 Honda Accord 4 cyl Two Wheel Drive Automatic 100K+ miles

When the transmission warms up, about a mile to two miles, it wont shift into third. It has a mild leak. Any suggestionsother than take it to a mechanic?

Hi TheInzane1,

Did you check the fluid level?
Is the D4 light blinking while driving?
Does it go into 4th when accelerator is released?

Recently bought this 1994 Accord. Made some repairs and has been running great for the last 2 wks. Today I was driving in town today, no more than 35 mph, when I noticed the transmission was not shifting properly. I brought it to a stop and tried again. It shifts fine from 1st to 2nd then holds rpms to about 2500 before shifting 3rd. That is as far as I went for fear of causing any damage. I did notice the fluid was in need of changing but I had not done it because I have made other more pressing repairs so that I could drive it work. I need some help on where to start diagnosing the problem. From the research I've done there is no servicable filter without pulling the tranny. Could it be plugged? Could the shift solenoid screen be plugged or not operating properly and how do you test. I do not believe it is shot because this was the first sign of a problem and I did not continue driving it. Hopeful anyway. Thanks waiting for response.

Is the check engine light coming On and last tune-up done? A badly needed tune-up will affect how the transmission operates.

Your transmission is slipping have it further checked out-could be clogged filter, valve body and shifting solenoid/s etc-

Tune has been done. Engine is running great. Had problem with VSS but it was replaced and has been working fine. I need to know to if there is anything I can do to diagnose and repair. I really do not have the funds to take it to a tranny shop right now. I'm a pretty good mechanic, I'm in need of some direction. Are there any easy checks I can start with and go from there, I'll pull the tranny to replace the filter if I have to. Are there any procedures that can be done by home mechanic.

You can try cleaning the valve body and also check filter other then these have it pressure tested to find out more

That tranny doesn't have a filter that is serviceable.