PoorDad

Car is 1998 Civic LX. 150k miles. This car has an automatic transmission. 4-speed overdrive transmission.

It started having trouble shifting and the check engine light came on. I took the car to a local mechanic and he read the code. Code came up as the throttle position sensor. I soon found out that the TPS is connected to the throttle body and that is sold as a complete part with the throttle body for around $500. I was able to perform a few internet searches and discovered that the TPS can actually be removed and replaced. I did that. Bought a new TPS from Rock Auto and removed the old one. Installed the new one. Got out my volt meter and clocked the new TPS sensor to the proper voltage with the gas pedal at idle and also at wide open throttle. All checked out.

Transmission still not shifting correctly. Check engine light still on.

So, I drained and refilled the ATF last weekend. Got about 2 and 1/2 quarts out when I drained it. Refilled with new Valvoline MaxLife Dex/Merc High mileage ATF fluid. This is supposed to be an acceptable substitute over the Honda brand name fluid. I don't want to debate weather or not I should have used original Honda ATF fluid. Valvoline specifically states on the bottle that is is an acceptable alternative to the Z1 Honda fluid. I did some research and made a decision to use the Valvoline because lots of people are using it and it seams to work fine for those people. So, let's not get side-tracked here and turn this into a pi$$ing match about what fluid I used. It's done.

Okay, so drained and refilled. Idled the car in the driveway until the engine temp came up to normal. Waited for the engine cooling fan to kick on once. Car should be at operating temperature now. Cooling fan kicks off. Engine at idle.

Now I put the transmission in REVERSE and backed the car down my street in reverse at about 10 MPH.

Then I put the gear shift selector into 2 and that forces the transmission into 2nd gear. It won't take off in 1st gear and shift into 2nd. It's made this way for snow travel. So, it takes off in 2nd gear. I drive it back up the street and around the block in 2nd gear - about 20MPH.

Now I put the gear shift selector into Drive. Take off and continuously advance the throttle to rev the engine and keep it in 1st gear as long as possible before letting off and allowing the transmission to shift into 2nd gear. Revved the engine to about 5k RPM before letting off on the gas pedal and allowing it to shift into 2nd gear.

Stopped the car.

Shift selector still in Drive.

Drove the car normally for about 10-12 blocks on a long slow street through my neighborhood. This allowed the transmission to start off in 1st gear - shift to 2nd gear and finally into 3rd gear. 95% of this run was in 3rd gear.

Now I stopped the car again. Put the shift selector into Over Drive.

Drove the car normally up to about 45MPH on a long stretch of road with no stop signs or lights. Transmission shifted normally and was in Over Drive for 95% of this run.

I was basically trying to force the new fluid into each separate gear.

Took the car home and parked it. Raised the driver side of the car and removed the transmission drain plug again. Fluid is bright red and warm. Drained it. Replaced with 2 and 1/2 quarts of the Valvoline again. Checked fluid level per owner manual - engine at operating temp - car off - transmission in park - fluid checks out at proper levels.

Darn thing still won't shift right. If I put it into Drive and run it normally, it'll start off in 1st and shift to 2nd. But when it tries to shift into 3rd gear, it slips badly. I immediately let my foot off the gas pedal to avoid the transmission slamming into gear when the throttle is revved up. When the RPM's come down to around 1000RPM - the transmission will shift into 3rd gear.

I've basically tried to replace as much of the fluid as possible in my drive way. I've tried to force the transmission into each gear separately - my thought being that the fluid will travel through the valves and ports for that specific gear and hopefully flush any gummed up stuff out of the way. I then drained the fluid again and refilled. But still no joy with the shifting problem.

I have not taken the car back to read the check engine code after replacing the TPS. I am pretty sure it'll just send out the same code again. I'm sure there's a connection in the way the computer reads the TPS and the shifting of the transmission. But I'll be darned if I know how it all works and how the computer regulates it all.

I'm tempted to let my wife drive it back and forth to the grocery store and our kids' school - about 3/4 mile away for the next week or two. See if the new fluid will wash anything out and hopefully un-stick anything inside that may be causing the shift problems.

Any ideas for this broke father and part time shadetree mechanic. I really can't afford a transmission overhaul right now?

Former User

Get the code pulled ASAP. It could be the TPS code or an unexpected new code. As you guessed, the TPS signal is used by the ECU to tell the transmission when to shift gears.

After you pull the OBDII CEL code(s), reset the ECU and drive the car to see whether the same code(s) repeats. Post all codes that repeat.

PoorDad

Will pull codes.

How do I reset the ECU? Simply remove + battery cable and wait a few seconds?

Thanks

96EJ6LX

I would look on your local forum and find a cheap trans and just replace the parts you need and keep the good ones. I know it won't prob be the best solution but it can help.

Former User

96EJ6LX

Wait at least 20 min. Your battery capacitor will hold your memory like radio and clock.

PoorDad

Thank you.

I'll take it back to the local shop. He pulls codes for free with a hand held machine that plugs in under the dash. This will be the 2nd time he's pulled codes for me - probably time to slip him a $20.

edit:
Thanks for the help. I gotta get to bed. My days start at 5am and it's past my bed time. I'll have my wife take it to the local shop tomorrow and pull the code. I'll reset the ECU and report the engine codes after I get home from work tomorrow evening.

Former User

Many auto parts stores will also pull OBDII codes free of charge.

PoorDad

My wife took the car to the closest auto parts store today. They don't have a code reader. She was scared to drive the car any further. She brought it home and parked it.

There's other parts stores in the area, but they are quite a distance and I have to admit, I'm a little scared to drive this car several miles one-way to a parts store.

I told my wife to take it to the automotive repair shop tomorrow and see if they guy will pull the codes again.

Former User

In the meantime, I'd recommend that you just jump the service connector to pull the code. It's pretty straightforward.

PoorDad

Okay, jumped the service connector and pulled the OBDI code.

The code is throttle position sensor. Thats the only code it's throwing out.

As I stated in my first post, I already replaced the TPS and clocked it to the correct voltage.

Pulled the 7.5amp backup fuse tonight and left it out for exactly 10 minutes.

Reinstalled the backup fuse. Started car. Temp cold. Drove the car with the shift selector in Overdirve (normal driving position) around the neighborhood until the engine came up to operating temp. About 5 minutes.

No more check engine light
Transmission seams to be shifting normally
Brought it home and parked it. Went inside and gave the wife a hug.

Went back outside and drove the car rather aggressively in a deserted industrial park near the neighborhood. I came to a complete stop 2 times and made sure the transmission shift selector was in Overdrive. From a dead stop - floored the gas pedal - forcing it to rev up to 6500RPM before shifting from 1st gear into 2nd gear. Held the throttle down. Shifted from 2nd gear into 3rd gear at 6800RPM. No signs of slippage. Backed off the gas pedal and allowed the transmission to shift into overdrive. Was going very very fast and would have certainly gotten a ticket if I'd been spotted. Fortunate that I was able to do this on deserted stretches of road in the nearby industrial district.

Made my way out of the industrial district and back into evening traffic. Drove the car normally, in traffic, for about 8 miles around town. Seams to be driving normally.

Is it fixed?

All I had to do was pull the backup fuse out of the fuse box after I replaced the TPS sensor?

PoorDad

My wife has been driving the car for a week since we pulled the backup fuse and reset the computer.

Car seams to be working perfectly.

Thanks to all who helped out. I really appreciate it.

vtec8483

Hi Poordad, Congratulations on your repair. We too have a 1998 Civic EX auto. trans with shift issues,check engine light showed TPS out of position. Which was replaced at a shop, I was out of town. Did not fix the "trans issue" They wanted to replace trans. and then I saw your post. Was wondering how I verify that the TPS is clocked to the correct voltage and is the 7.5 amp backup fuse easily located ? Thanks for any help you might be able to supply.

PoorDad

There's 3 wires on the TPS. You need to use the volt meter to check the position.

Grab a couple sewing pins or needles. There's 3 wires. I don't remember which 2 I used, but if you stab through the outer wire insulation on 2 of them, it will register voltage. Just stab the needles through the insulation and hook it up to your volt meter. You want to put the volt meter on DC voltage and less than 20V setting. Plug the 2 leads on the volt meter into the needles.

With the car OFF, turn on the key to the RUN position. DO NOT start the car. Do not touch the gas pedal. Voltage should read about .50 or .55 volts.

Now floor the gas pedal all the way down. Voltage should read 4.55 volts.

If this is not correct, you can loosen the bolts and turn the TPS slightly clockwise or counter-clockwise until the correct voltage is displayed on the meter.

If you had a shop replace the TPS, they may have done it with a factory replacement. Thats the entire throttle body. Costs about $500 to buy it. On the stock throttle body, the TPS looks like it's not removable. It is. You just use a dremel and grind a slot in the head of the bolts that hold the TPS into place. Now use a screw driver to loosen the bolts. It's REALLY easy.

Adjust the TPS if you have too. I am not sure if the voltages I posted here are exactly correct. It's been awhile and I don't remember exactly. You should be able to do some searches here or google and find the exact voltages on the TPS.

The RESET fuse is EASY to find. It's under the hood. There's a small black fuse box located on the passenger side fender. Right next to the battery. On our LX, it was on top of the rounded part of the wheel well. It's practically staring you in the face. Open it and locate the 7.5 amp fuse. It's a little bugger. Ours was pink. Pull it out. Go have a beer or smoke a cigarette. Come back in 10 minutes and put the fuse back in. Your computer is now reset to factory baseline specs.

Turn off all accessories. Turn off the heater fan. Turn off the radio. Turn off the lights and the windshield wipers. No power drains.

Start the car. Don't touch the gas pedal or turn on the radio. Don't turn on the heater. Don't step on the brakes. No power drains or demands on the electrical system.

Let it idle for about 10 or 15 minutes. Let it idle until it comes up to normal operating temps.

The RESET fuse should have made the CEL on your dash go out. If the shop replaced your TPS correctly and clocked it correctly, the cars computer will take new readings of everything and adjust so that the car drives normally.

We've been driving the car. It shifts and drives normally. We've put about 2k miles on it. No more transmission issues.

Hope this helps. Good luck!!

vtec8483

Poordad, it worked like a charm. Shifts very smooth now! That for the quick response and great help.

PoorDad

Thats awesome vtec8483! Glad it worked out for ya.

mpavon22

Hi I also have the same problem on my civic 98 lx automatic, the rmp rev up when switching from 2nd to third gear. I'm new to honda cars and I'm trying to get a tps for my car. Every auto part store I call they tell me that my car does not require a tps, only ex dx and hx. Can somebody please help me

PoorDad

Your TPS is here.

Drill into the catalog. It's under fuel/air. $26

http://www.rockauto.com/catalog/raframecatalog.php

PoorDad

The auto parts stores don't see the TPS in their catalog because it's sold with the entire throttle body assembly. See my earlier post. The throttle body assembly DOES have a TPS mounted to it. But that throttle body assembly is $500.

Locate the TPS on the side of your throttle body. The TPS looks like it's held in with rivets. Not true. You can take a dremel cutting wheel or even a hacksaw and cut slots into the heads of those 'rivets'. You can then remove the TPS with a flat head screw driver. They are just screws with a head that snaps off from the factory. They are threaded and will unscrew very easily with a flat head screw driver. Remove the TPS and replace it. No need to spend $500 on the entire throttle body assembly.

Now you have to 'clock' it properly. The new TPS will have slots in the mounting holes so that you can twist the TPS unit slightly clockwide or counter-clockwise.

You need to go back and read my earlier post on how to hook a volt meter up to the new TPS wires. Follow the instructions on adjusting the position of the new TPS. Get it 'clocked' into the correct position so the volt meter readings are correct. Tighten the screws.

Remove the back up fuse under the hood to reset the computer. Wait 10 minutes for the computer to go completely dead. Replace the fuse.

Be diligent about not creating any power drains on the vehicle when you start it. Open the door. Sit down. DO NOT step on the brake - it's an automatic and should be in park. Turn off all accessories. Wipers - lights - turn signals - radio - heater motor. NO POWER DRAINS!!!

Do not step on the gas.

Start it. Do not touch anything. Do not rev it up. Don't turn on the stereo. Don't touch the heater controls. Just start it.

Open the door and walk away.

Let it run for 10 - 15 minutes.

Go test drive it.

Good luck!!

shixynazz

Hello everybody, im sorry to start up an old thread but i JUST created an account and am brand new to forums so bare with me haha. Okay, so i have a '98 Civic LX 4 door sedan that has this shift flare(?) not too sure if thats an accurate use of the word, but what happens is, at a light acceleration, in 2nd gear about to shift into 3rd, it seems it flings out of the end of 2nd and catches into third, causing high rpms in between. Every other gear including Reverse works fluently and strong. But the only times this does not happen is when the car is first started and cooler than running temp. it also doesn't happen if i give it a hefty foot on the gas pedal. So, Ive been on countless blogs and articles and watched tons of videos trying to do my research and figure out what the heck makes this shift flare happen!

What I've done so far:
So far from all these forums and threads, Ive seen things from changing solenoids, fluid flush, and replaced and re-calibrated Throttle position sensor, checking all major grounds, which doing each of these separately fixed others problems. Also, someone contacted Honda in hopes that there was an update to the PCM? turns out their isnt one so thats out the window. But, with that said , I've flushed transmission oil 3 times, replaced the shift solenoid pack on top of the tranny with a good one then re-calibrated it to 4.5v full throttle and .52v closed throttle and triple checked after fastening. (I think its called "shift pack A&B" or "lock out solenoid"?), Ive checked and cleaned every ground i could find on the car, and triple checked all fuses and wiring. Yet, nothing seems to make any difference in this shift flare. One thing I am unfamiliar on how to do or where it is, is to change the Transmission fluid filter?

My main goal here is to try to fix this flare hopefully with doing something externally of the transmission, and also seek help for places to check that I haven't, or should check again, just any locations that correlate and could have any participating affect in the problem. i know that theirs another shift solenoid pack on the bottom of the tranny and i think a couple other things but im not familiar with transmissions so I wouldn't know what they actually are and if they could be the culprit by malfunctioning or getting incorrect v's. If anyone has had this problem and solved it please tell how or what fixed it, also if anyone has an idea what i should try next please let me know! Thanks in advance! - Kyle

Former User

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