90 Q45 shift solenoid 1st gear issues.

[white90esex]

I hate starting new posts for dumb questions but at this point cant figure out what happened.


Press brakes, no click from solenoid. Brake lights do come on though so the switch on the pedal is obviously functioning. Press shift lock button and I can shift into gears fine but when putting it into 1st it stays in second. Ive got all the plastics off and I can see whats hitting and what not. I seem to hear a faint click from in front of the shifter that I cant identify where its coming from.

Gonna possibly pick up a TCU from a new car that starts in 1st to eliminate the whole 2nd gear junk but for now just want to see if I can pinpoint whats causing this.

Thanks for any insight.

[Q451990]

So you're unable to shift out of park without pressing the shift lock button? If so that's probably a fuse. It's typically the one that's blown when the brake lights aren't working though. The two tips on the 1157 bulbs tend to melt together causing shorts in the lamp socket.

The not shifting in to 1st... I actually had two transmissions on my first Q swapped out under warranty because they wouldn't allow me to manually shift in to or start out in 1st on the first drive of the day. It turns out that the transmission must be fully warmed up before it'll let you use 1st gear manually. I think the first gear start TCU changed all of that - but with a 90 Q in it's stock form, it'll block out 1st unless the transmission temperature sensor says it's up to normal operating temperature. If you have a bad thermostat that is slowing down your warm-up times, it makes the problem worse.

[white90esex]

hum. interesting.

Yeah ive been wrenching on this car for a good while now and id say the last time it was moved was 8 months ago. I did go into 1st then and cant find anything that could have changed since. maybe just go 5 or 6 speed manual. Really didnt want to cause then im sure ill beat on it. just wanted something to put into drive and go.

[white90esex]

So jumpered the solenoid and its working. So maybe something to do with the green box (shift lock control unit or whatever).... Still not sure why it wont go into 1st though.

Along the lines Ive also fixed sunroof issues as well as the blower motor problem. slowly sorting this car out.

[white90esex]

Fix one problem and another pops up.

Just noticed the little display saying Head lamp, Tail lamp, Stop lamp inoperable. But all are working. So, my car is being dumb and things s*** is broken so maybe thats why it wont shift out of park and wont shift into 1st. Idk at this point. Basically chasing hopes and dreams anymore.

[Q451990]

Yeah, if it can't read the stop lamp signal that would prevent it from shifting out of park.

[white90esex]

Yeah it's odd that the lights are functioning correctly but somewhere in the car it thinks it isn't. But it is. Idk what I did lol. f*** electrical hurts my brain

[white90esex]

I hate you car lol. FML. Just gonna 5 speed and black out this fooking display.

[goody90q45]

Its probably a bad brake sensor in the trunk. Its a small box below the trunk lock behind the trim piece. Possibly a melted solder joint inside. Open it up and see if there's anything obvious. Post up a part number.

[white90esex]

Its the pink one I believe so ill check it out. I dont understand why it wont come out of park without the shift lock button being pressed and the damn 1st gear isnt working.