Hi all,

I know this has been asked before but I seem to be up against a wall on troubleshooting and fixing. It seems a lot of threads ultimately go unanswered or are a simple fuse replacement.

I have a 1998 automatic Civic EX that is currently stuck in park.

#1 - My brake lights do come on when I press the brake pedal. All three - left, right, and center.
#2 - I checked the #7 under-hood fuse (30A) -- it is a larger "square" type fuse that I am not familiar with but it appears good.
#3 - I hear no clicking coming from the center gear shift area when I apply the brakes.
#4 - I can use the shift lock release with my key to get it into neutral - then start the car and then put it into drive.

Today I disassembled the brake switch.

After I unplugged the brake switch, it has four metal tabs inside of it.

The top two (small tabs) are open (reading of 1) when the brake is pressed. And, completed (reading of ~032) when the brake released.
The bottom two (large tabs) are completed (reading of ~068) when the brake is pressed. And, open (reading of 1) when the brake is released.

I am not sure if that is telling me anything useful or not. Or, if I am measuring the switch correctly. Not sure if the top/bottom tabs are paired or if the left/right tabs are paired. If I measure the left/right pairs of tabs, I get an open reading (reading of 1) no matter if the switch is pressed or not. Again, not sure if I am measuring the switch correctly.

I then took apart the center console and got down to the guts of the shifter. I can see the mechanism that release the shift lock and I can see the actuator. The actuator makes no noise nor does it move when the brake is released or engaged. Car not running.

I unplugged the plug from the actuator. Very tiny. I tried to use the multi-meter on the plug as well. I again used the completed circuit function,

The multi-meter read open (reading of 1) no matter if I pressed the brake or not. Again, I am not sure if I was reading this correctly or not. The car was not running.

I have been trying to research this in other threads and forums as well and I keep getting conflicting fuse numbers. My brake lights and horn work. I originally checked fuse #7 under the hood. Are there other fuses I should check?

There is also mention that the actuator can be removed and powered directly as a test. How do you "power it directly"?

If anybody has any further instructions or ideas, I would be greatly appreciative.

I am doing my best to baby this car so that I can get historic plates for it!!!

Thanks!

 

Since your brake lights do work, these are some other possible culprits:

• Blown fuse – Under-dash Fuse no. 33 (7.5A) and/or Fuse no. 25 (7.5A) – Not likely to be due to blown fuses if there are no other problems.
• Wiring issue - short or open (break) in wiring
• Brake pedal position switch
• Throttle position sensor - The voltage needs to be at less than .5 volts (this essentially tells the ECM the accelerator pedal is not depressed and the throttle is closed). If it is at a higher voltage, the ECM thinks the accelerator is depressed and the throttle is open and prevents the shift lock solenoid from energizing (you won’t be able to shift out of Park).
• ECM (Engine Control Module)
• TCM (Transmission Control Module) - Signals from Brake Switch and TPS has to go through TCM before it gets to the ECM)
• Transmission Gear Position Switch – Is the P light on? Can be faulty even if P light is on.

This is how the shift position interlock works:
When you push the brake pedal, battery voltage is sent through a Grn/Wht wire to the TCM, then the ECM. If, at the same time, you do not push the accelerator pedal, a low voltage signal is sent from the TPS through a RED/BLK wire to the TCM, and then the ECM. The ECM then applies voltage through a WHT/RED wire to the shift lock circuit in the Interlock Control Unit. When you move the A/T shift lever from the PARK position, ground is provided to the shift lock solenoid. The solenoid is then energized allowing the shift lever to be moved from the PARK position.

The issue may be due to the TCM and/or ECM. Many times after so many years, the capacitors inside go bad. You can open them up and examine the resistors and capacitors.

 

Thanks for the quick reply and the great checklist!

So, I am trying to narrow down which items I should check/replace first by starting at the top of the list and working my way down

#1 - FUSES - checked fuse 33 and 25. Visually and with multi-meter. Both are good.

#2 - BAD WIRE - too complex to track down now

#3 - BRAKE PEDAL POSITION SWITCH - Based on my original post:

Is it possible that the brake pedal position switch could still be the culprit? Is there any way to test this further? Or, for $10 should I just get a new one and check it off the list and go from there?

Thank you!

 

The list is not in any specific order of the possible cause.

To easily rule out the brake pedal position switch, just disconnect the connector to the switch. Then insert a jumper wire or small paper clip in the connector's terminal cavity where the Wht/Grn wire is to the terminal cavity where the Grn/Wht wire is. If it still doesn't shift out of Park (when you have the issue), it is not the brake pedal position switch.

The ECM is located behind the right kick panel.

 

Thanks for the quick reply.

I will check these things out as soon as I can.

Thanks!

 

Based on some other searches I did, it appears for the 1998 Civic EX that the ECM and the TCM are combined into one unit.

Can you confirm this?

Thanks again!

 

It is. As in the same box. Different circuit on the board but still a part of the ECM box and board.

 

If it was a CVT, then there is a separate TCM and ECM. Non-CVT had just a PCM.

 

When I jump the white/green and green/white terminals (these are the top and bottom on the right side when looking at the plug) with a paperclip, should the brake lights turn on?

Also, when I meter the solenoid plug to see if it is getting 12v, where would be a good ground location that a can reach with a multi-meter? I have a gut feeling that I am not getting a good ground...

I took my drive-side kick panel off and I do NOT have any sort of box at all in that area. It is just an empty cavity.

This might be a REALLY dumb question, but does the car have to be running for these tests to work?

Thanks again!

 

1. The brake lights suppose to go on if those terminals were jumped, which would be the same case if the brake pedal was plugged in and the pedal depressed. -- Brake lights will work even if the car was not turned on.

2. The Shift Lock Solenoid does require the car's ignition to be in the ON or START positions (can be running or not).

With the ignition in the ON position (car not running), you can check the connector for the Shift Lock Solenoid for power on the Yellow wire (power). You can touch the multi-meter's black lead to chassis ground, such as the bare metal chassis at the rear of the shifter.

With the brake pedal depressed, you can touch the multi-meter's black lead to the Yel/Blk wire (ground). If there is a voltage reading by touching the black lead on bare metal chassis ground; but, no voltage reading by testing with the black lead on the Yel/Blk wire, then it may indicate the ground signal was not send through the interlock system.

3. You can also test for continuity to ground on the Yel/Blk wire with the brake pedal depressed and the ignition in the ON position.

 

Thank you again for the more detailed explanations.

When I jumped those terminals my brake lights did NOT go on. But, when the brake switch is plugged in, the brake lights do go on when I applied the brake. I guess I just did not jump it correctly. I will try that again and I will also try testing the solenoid as you outlined.

Work days are back so it might take me a day or two to do this.

Thanks again!

 

This is just an idea for an inexpensive workaround if you don't want to keep trying to find the cause of the issue.

You can get a momentary switch, then wire one end to chassis ground. The other end you can just unplug the connector for the Shift Lock Solenoid and insert into the terminal cavity where the Yel/Blk wire is, then just plug it back into the solenoid. (Or you can splice into the YelBlk wire.) Yel/Blk is a yellow colored wire with a black strip running through it.

You would press the momentary switch to send a ground to the lock solenoid and shift out of Park.

 

Thank you for the additional idea.

I am hoping to have some time this weekend to test more and implement something.

Thanks!

 

I spent the better part of an hour testing what I could. Nothing panned out to be an obvious issue. I tried several times to jump the white/green and green/white tabs of the brake switch plug and I could never see my brake lights come on. However, the brake switch does work and turn on the brake lights when I would plug it in. I know I am not a mechanical genius, but I was confident enough that I could figure that out. Oh well. Hooked the brake switch back up and the brake pedal once again turns the brake lights on and off as it should.

So... I took your recommendation and wired in the above circuit. I used one of these to tap into the yellow/black wire as you suggested. I just stripped the other end bare for a quick test. Touched it to a bolt connected to the chassis n the center console. And, low and behold the actuator switched on. Yay!!! Thank you!

Now, I need to go out and get a momentary switch to wire in line and permanently secure the other end to that bolt.

I could either get an OFF/Momentary ON switch and mount it next to the center console.

Or, I was thinking, I could get an ON/Momentary OFF switch and mount it next to the brake switch so that the brake pedal actually engages it as it should.

At least I have options now and I thank you for the detailed info and hand-holding that you provided!

 

I didn't see where you checked the throttle position sensor. All the safeties are kinda in series. All conditions have to be met in order for the shifter to to be able to move. I had that problem with my honda civic and that was what fixed it. Replaced throttle position sensor.

 

I read somewhere, the integra or civic fsm, that the tps had to be at a certain voltage range in order for the solenoid to release the lock as well. This would keep you from damaging the transmission. Might be that too but seeing as how this is an older car I would think the solenoid is bad.


But then again with my recent experience on an auto db7 it turn out to be a fried tcm that cause the shift lockout and the transmission to not shift correctly..... I was lucky enough to find one in my stash of parts (kept one in case I got bored and wanted to do an automatic b in a 96-00 civic, hate me please) and my sister was back on the road.

 

Hey guys,

Sorry for the tardy reply. Life. You know...

I did not check the throttle position sensor because when I researched it, it doesn't seem that I am not having any of the other "symptoms" of a bad throttle position sensor. However, it seems easy enough to check really. So, yes, I will do that (hopefully this weekend).

In regards to the TPS, if that is what ends up being the issue, it seems like a big issue (money wise). I was doing some research and it appears they are a couple $100 dollars and if I am understanding correctly, it appears you have to take it to a dealer to have them programmed (which seems to be even more money). I don't think my 22yo civic is quite worth that amount of money investment.

I greatly appreciate the continued suggestions and support.

Thank you!

 

TPS is throttle position sensor and dealer doesn't mess with them, they have snap away bolt screws. They just replace the throttle body complete to replace a tps. You can do it yourself for the cheap but you need to dremel slots into the screw heads so you can get it out.

First just use a mulitmeter (volt meter) to check the TPS.

If you need information on how, just let us know.

 

I am sorry, I majorly misspoke.

I meant all that regarding the ECM/TCM. Not the TPS.

Yes, the TPS is the throttle position sensor. I found a YouTube video on how to test the throttle position sensor. Hopefully I can do that this weekend.

Thanks guys!

 

I know this has been a LLLLLLOOOOOOOOOOOOOOOOONNNNNNNNNGGGGGGGGGGG time coming. Life in general got busy and the Civic is our third car and rarely gets driven so it was low priority. But, I hate when people abandon threads, so I wanted to reply and give an update.

I tested various components as much as I could. I am 99% sure it is the ECM/TCM which I am not going to replace on a 23+ year old car.

I ultimately took tech8's advice and wired in a momentary switch circuit for the shift actuator.

What I did was I purchased a second brake light switch and fashioned a bracket and mounted it up under the dash so that it works just like the factor brake light switch. But, this brake switch is wired inline and acts as a momentary switch for the shift actuator.

So, press the brake and the shift actuary disengages so that you can shift. If the brake is not presses, the shifter won't shift.

It's not perfect, but this is as close to the way it is suppose to work as I could get it and still be safe. All for about $12 bucks total.

Thank you to all who gave advice and helped along the way!!!

 

I had the same problem on my 1990 civic si automatic.
I took the shifter selector apart on the passenger side of the shifter and cleaned the brass area of it with electro contact cleaner and a fine emery cloth, after that it was good with no more stuck in park and key stuck in ignition and the lights on dash showed it in park all the time now when before it would not light up the p when it was locking up

 

If you isolate it to the ECU/TCM you can also hit the u pull salvage yards and sometimes get lucky and find your ECU. However, they are a hot commodity and you usually have to go the same day the car hits the yard to get em. Save yourself a ton that way though.