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2003 DTS
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Discussion Starter #1
I have a 2003 Cadillac Deville DTS and one day it just randomly wont shift out of the PARK position. If I use the shifter lock override slot, I can get the car to shift and it will drive normally. But as soon as I put it into park it wont shift past it unless I press that button. I already checked the codes and there aren't any. Any idea what the problem could be?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,423 Posts
Shift interlock solenoid itself or the brake light switch (top of brake pedal arm) is mis-adjusted.

Just for kicks, lift the brake pedal up with your foot as far as you can, depress it as far as you can - twice. Brake/Shift interlock OK ?
 

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2002 DTS
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5 Posts
I have this exact problem, I read some where it is a sensor on the brake..researching, will post anything I find
 

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96 ETC 03 DTS, 77,81,83,89,91 Devilles, 79,82,91,92 Brougham
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I also have a 03 DTS and it was doing this same exact thing on a regular basis. Taking things apart and doing a major cleaning helped but I sense the problem may resurface anytime because I haven't replaced anything yet. Its amazing what can accumulate under that shiftier via falling through the cup holders. If the brake lights and cruise function normal chances are its the shift solenoid itself. You should feel and hear a slight click in the console each time you press the brake IF its going to allow you to shift out of park.
 

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I helped my old friend to fix his problem with his 2000 Deville DTS common problem: 'shifter stuck in park', he had to use manual interlock release by push forward the orange linkage located under neat of the console rubber mat (just before the shift lever below the ashtray), that orange linkage action pushing the solenoid out off lock position, the shift lever is free to shift to gears; This safety feature is applied on all auto transmission in this model car: step on the the brake prevent the car move before shift to reverse first gear of shifter position, other older models, there a button on the shifter lever, driver has to push before shifting or it locked will not shift out of park without push that button. In this model car the orange linkage has same function: manually take the shift lever out of lever lock at park, it does no harm but annoying you have to do that every time, specially when you in hurry...
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OK now back to my finding and fixing the problem save my buddy a bunch $$$ and I hope it may help some others have same problem from now on.
There 3 main things that caused this problem are: (1) The shift interlock fuse, (2) The brake pedal switch, and (3) The shift lever interlock solenoid control module (in the shifter assembly unit).
First thing I did (recommend do this first before dismantle the shifter assembly) checking to locating the source of the problem: Take out the top center console cover the shifter assembly (make sure to disconnect the traction control switch connector under neat before set it aside) and locate the shifter interlock control solenoid electrical connector (a 3-pin connector, attached to the RH side of the assy. frame);
Turn ON the ignition (NO need to start the engine) and use a multimeter/voltmeter (or light bulb) with 2 needle-pointed-tip probes to probe at the interlock control connector (3 pins) pins: pin 1(green /white stripe), pin 2(red, center pin) , pin 3(black)... (Note: the wire colors may different on some cars mfr'd in US/ Canada: Green/white could be Yellow, Red could be Purple)
Probing & indications:
Test (1)- Connect meter to pin 2(red (+)) pin 3(black (-)), Battery power 12V is always there when the ignition is ON, has no effect on brake pedal actions) this power is applying to solenoid circuit (this meant fuse is good, in case missing 12V here, check the Shift Lock Solenoid fuse locate at under neat rear passenger bench seat fuse box, very rare case with the short circuit at the shifter).
Test (2)- Connect meter to pin 1(green/white(+)) and pin 3(black(-)) given these indications when ignition is ON:
There is 12V appeared at pin 1(Green/white) when NOT applying Brake: the safety feature is ON, this 12V applied to solenoid control circuit turned off power to the solenoid, the solenoid plunger automatically pushed out by solenoid spring to lock position, shifter is locked at Park, and when Brake is applied the switch at brake pedal also brake the 12V supply to pin 1(green/white) become 0V, this action turned on power to activated solenoid, retracting the plunger in,(the locking pin) mechanically out of lock position free the shifting lever) these conditions indicates good working switch at brake pedal good working safety feature, if the locking circuit working good and no matter brake applied or not, the voltage found at pin 1(Green/white) always 0V: the safety feature no longer affect (OFF), shift lever never locked at park and if it's voltage found always 12V (even when apply brake): the safety feature is always ON, shifter always been locked, these condition indicate that the switch at brake pedal is bad, it does not make contacts when brake pedal at ease (NO brake applied) or does not break the contacts when brake is applied, this case replace the brake pedal switch(lower one with 2 electrical connector attached).
If the voltage results are good as described in both test (1) & (2), the problems existing at shifter assembly solenoid lock control circuitry or the solenoid itself. (Fixed & tested in may case describing below)
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Components location and disassembling:
(1) The fuse is located in the rear fuse box (under neat rear bench seat, pull bench seat up & forward and out the fuse box is found on the left (battery is on right) and diagram on lid will locates the fuse location)
(2) The brake pedal switch located above the brake pedal at end of lever (in this model car there're 2 switches at the brake pedal (the one located below with 2 electrical connector, one connector for the rear brake lights, one connector for shifter interlock), it's easy to locate & disassemble (twisted 1/4 turn CCW will pop out).
(3) The shifter interlock solenoid control module located at the shifter assembly, (disassembling by use plastic wed tools pry along the sides (approx at 4 corners) of top center console & lift up the top cover disconnect the traction control switch connector and set the cover aside; Disconnect the transmission link cable using flat screwdriver pry the connecting end cable pop out from the lever connecting pin and the yellow retainer upward out from the frame to free the cable; Dismantling the shifter assembly: With 1/4" ratchet, extension and 10mm socket (best use with a magnet ready socket prevent losing nuts) to unscrew 4 nuts holding the assembly to floor, there're 2 electrical connectors at assembly one on each side of the frame, one on the left (4pins) for floor shifter indicator light & instrument dashboard shift position indicator, one on the right (3pins) is for shifter lock control solenoid (tests performed on this one).
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My case here was testing good at the solenoid control connector as described test(1) & (2) above.
With the procedure(3), I took the shifter assembly out to the bench and I found 2 broken wires at connections soldered to the circuit board & loose solder joints (cold soldered) on the solenoid voltage control circuit at the solenoid input pins,(to me these electrically problems seem to be common, due to the vibrations for years & deterioration of the materials by weather condition etc... my case, the Red & Black broken wires are 12V supply & Ground to the circuit that is there're no power no operation occurred; these problems (broken wire connections) are not obviously seen, they are hidden behind the plastic cover).
To gain access to the solenoid circuit board on the shifter assembly, I pried the black plastic cover off, desoldered 2 solenoid input pins then pulled the circuit board totally out from the assembly for easily examining/working on the circuit board; while solenoid free from the control circuit, I use 12V supply applied to solenoid input pins to test the solenoid operation to make sure the solenoid is working the plunger in/out normally as power applied/disconnected, Examined the Green/white wire connection it's still barely connected to the board by 2,3 stranded wires, others all broke off separate from the circuit board; I desolderred all together & make new connections solder for all 3 wires to the circuit (from Right to Left order on the circuit board: Green/white, Black, Red), put some heat transferring compound on the isolated back of the power resistor, then placed circuit board over the solenoid input pins through their holes on circuit board & resoldered them in place; then performed test, (which I did not do at the first failed attempt), for proper connecting the wires I applied 12V (+) to pin 2(red), (-) to pin3(black) & watch the solenoid activated as it should (retracting the plunger, lock pin out of lock when 12V applied & released it into lock by the solenoid spring when 12V is off, It's working OK then secured the plastic cover over the board with a zip-tied (work fine with silicon sealant if you prefer).
(At first attempt it didn't work: I soldered wires (red & black, the broken wires) in wrong places (and I did not perform operation tested), I thought they would go with same order as the connector (Green/white, Red, Black) but is not on the circuit the order from Right to Left: Green/white, Black, Red).
After put everything back, reversing process as of disassembled them, the shifting operation returned to normal with the safety feature: Shifter locked at Park, and Apply Brake be able shifting out of Park at ignition ON operation perform smoothly as it should be... and... my old buddy's really happy after days of frustrating, we drove it for a final test ... to the bar.😎
... It's little too late for few were already spending $$$; but I still hope this lengthy explaining text above could do some help to someone (Cadillac Deville enthusiastic as my old buddy) on some cases... good luck.
 
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