94 GXE Automatic 133k

For about 2 months now on the 94, I have noticed my shift solenoid not "clicking" consistently when I push down on the brake to shift out of Park. Here is how it will behave:
* Sometimes it will "click" on the first push of the brake

* Sometimes if I push the brake down 3 or 4 times the "click" will be faint and then will "click" like normal

At about the same time, even when a "click" could be heard, shifting out of Park was much stiffer than in the past. Shifting in any other gears have not noticeably changed.

The first step I took was the el-cheapo route: replacing the 2 shifter bushings: the one above the cat and the one on top of the transmission.

While the overall shifting into a gear is somewhat smoother, it is still stiff when shifting from Park and the solenoid clicking remains intermittent. I was hopeful the new bushings would alleviate the stiff shift from Park, but they did not. I didn't think the solenoid would be affected at all, and it was not as well.


In doing some dot orgy 3rd gen forum research, I have discovered the following:

Matt [93SE variety ] has stated that there is a switch on the brake pedal that should be checked/cleaned and also says the switch in the solenoid is bad. A few others have stated this as well.

http://forums.maxima.org/showthread....shift+solenoid

http://forums.maxima.org/showthread....ght=shift+park

dc944 says that the 2 switches at the brake pedal are for:

Switch 1) Cruise control only
Switch 2) Brake lamps only

http://forums.maxima.org/showthread....threadid=55238

He alludes to a control unit on the passenger side foot well (I assume near the keyless entry box) that could be faulty. I've seen maybe one or two other people discuss this "control unit".

He contends that if the brakes are lighting properly, then that eliminates that particular switch even if it is controlling the solenoid switch as well.

Matt93SE's suggestion of hooking the shift solenoid direct to a +12V source is what I intend to do tomorrow. Other than that, I'm not real sure how to proceed.

Any other thoughts or opinions out there?

 

Courtesy of Matt93SE

Check the FSM first (or do a polarity check with a test light) before you stick +12V to the solenoid. It takes a ground pulse.

The intermittent connections are USUALLY caused by dirty contacts on a switch, but not always the case. I could check the switch on the brake pedal first.

BTW.. the brake light or CC switch are probably the same one that controls the shift solenoid. Dunno which one, but one would assume it would be the brake light.

 

Courtesy of abdul

My experience was to check the shift module control unit by the passenger door kickpanel. I had the same symptoms and the unit is about ~$75-80. Replacing it cured the problem. The relay inside it is a micro-relay and it went bad. Looking in hindsight, I probably could have replaced it for about $5 from digikey.


BTW the shift module is what always goes; the solenoid does not. I ran the 12 volt test and the solenoid clicked fine. I have access to an Alldata system and that control unit was an "item of customer interest".

Translation from Nissanspeak = Always breaks down

 

Courtesy of Craig B

The location of the shift module control unit is directly behind the passenger side kick panel. There is one screw in there and then you can pop it off (may need to remove door sill, can't remember for sure).

It's on a bracket that goes into a hole that goes towards the outside of the car. There will also be 2 relays (probably blue) right next to it. It has 15 wires going into it.

If you know how to solder or know someone who does, it may be worth a shot to take out the shift module control unit and resolder all the joints.

 

More courtesy of Craig B

Do you have a FSM?

If you do, there is a special section in the AT section about shift lock system and diagnostic the system does use the brake lamp switch above the brake pedal which is the one with red/yellow and red/white wires in it.

It looks like there is a small 5 wire harness going into the shifter assembly (if you pop off the shifter panel, it'll be coming from the ebrake area). It's actually a 6 wire harness with 4 on the bottom row and two on the top row, but only one of those top ones is used.

There should be a light blue wire in one the the middle two of the bottom row (not sure which side is L/R). This wire should get 12V when you press the brake pedal and 0 when not pressed. This is shift lock solenoid output signal. If you are having troubles, you could just wire this to +12v ignition (not constant so people cant move the shifter when the car isn't on).

I mentioned you could put ignition source to that wire to energize the solenoid. You could do this by a switch or something if you want, but you could probably do it easily with just a little jumper. If you look at the shift module control unit (in the kick panel), you will find the light blue wire there also (goes from this unit to the shift solenoid). Right next to the light blue wire at the main unit is a green wire which is coming from the fuse box and is an ignition source. I'd say unplug the whole harness going into the main unit and just put a jumper across those 2 wires and see how that works.

The only concern is that then the shift solenoid would always be on when ignition is on and it may burn it out or something. I'm not sure about that part.

 

Wow Bill, your Kewl

 

Try holding down the brake one time when the solenoid doesn't click and jiggle the shifter back and forth. If this frees up the solenoid I think your problem is the transmission inhibitor switch. I've had one go on my '89 and one on my '91 with similar symtoms. They corrode inside to the point of just about seizing up, making shifting stiff and therefore putting pressure on the solenoid. The other thing you may notice is you shift indents have moved slightly. This also confirms this switch because it controls those stop points. Hope this helps!

 

Right now, I doubt it's the inhibitor switch. The issues that would lead one to think inhibitor switch just aren't showing themselves.


I'm following the shift lock diagnosis procedure in the FSM and I haven't isolated the problem down. One thing I now understand better is the shift lock control unit in the passenger footwell clicks consistently when I push on the brake. The issue is the shift lock solenoid isn't consistently clicking.

As I described in the first post, the shift lock control unit clicks each time I push the brake pedal, and it can be several times before the actual shift lock solenoid clicks. This explains why I would hear a "faint" click before hearing the relatively "loud" click of the shift solenoid. The "faint" click is the relay in the shift lock control unit operating behind the passenger footwell where it can't be easily heard.

I thought it was the shift lock solenoid not having a strong path to ground and/or inproper voltage.


I'll continue to dig.....

 

ok...im way 2 stupid for all this stuff...but are you talking about the thing that clicks to let u out of park when u press on the brake? i had 2 replace mine...when i took it apart the connections and everything were really corroded so the unit probably wasnt bad, the connections were...this was the part underneath the shifter itself...spensive little bugger 2...like $70 or sumthin

 

It can be the solenoid itself. It can also be the shift control unit (discussed above), which is basically another relay that sends a signal to the shift solenoid to operate.


I would rather not throw money at a problem, but rather make sure of what is wrong.

The solenoid passed a bench test (direct 12V hookup and it clicks consistently), so it's down to the signal delivered by the shift control unit or the wire running from there to the harness that the solenoid connects to.

The FSM procedure was not combed over very well, even in the '94 FSM version. There are inconsistencies and vagueness and oddities in their approach to testing which makes it all the more fun.

 

tru...i see your point...maybe u could bypass the harness to see if thats the problem? i know mine was all corroded to hell...i had 2 use the little button to get outa park for a while...of course it could b sumthin else cause i think mine went b/c the guy that had the car b/f me spilled all kinds of stuff (i found french fries and all kinds of crap in the car, and i imagine he spilled coke of whatever down there and it corroded stuff...gaw)

 

If you should need any parts and want the cheap way out I got most of those things on the '91 I'm parting.