2005 S60 shift interlock partial function Topic is solved

[jbeebo]

Have a 2005 S60 2.4L non turbo automatic trans 165k miles, with a strange issue. The shift interlock solenoid only works to disengage from park. Once out of Park, I can freely move the shift lever to any other position - without stepping on the brake pedal - regardless of vehicle speed - without depressing the gear shift button. This is concerning, an accidental bump of the shift lever could slam it into reverse while going down the highway I haven't had this car very long, it's always been like this.

The gear shift button is mostly broken; that obviously needs to be replaced, but I don't think that's causing the strange shift interlock function. I partially disassembled the center console and checked the shift solenoid - it does work. In Park when I depress the brake pedal I can observe and hear it move. Once out of park, solenoid no longer changes state, it's constantly energized (i.e. plunger pulled left).

I understand the way it should work is as follows (all in key position 2):
-in park, brake pedal controls the solenoid. Brake on = solenoid energized, shifter can move out of park to any gear position.
-in drive, the solenoid should be turned off, and a spring pushes the plunger to the right. Shifter is allowed to travel between N any of the drive position. Shifter is prevented from going into Reverse.
-in reverse, shifter should be turned off. Shifter is allowed to move between neutral and reverse. Shifter is prevented from moving into drive or park.

I'm not sure if vehicle speed factors into the equation. Have never driven another P2.

I read this post, which says the gear shift indicator panel is the controller for the shift solenoid. Does this mean I have a faulty indicator panel?

Someone has been in there before to install an aftermarket audio amp, I wonder if he damaged something.

Any hints or advice greatly appreciated.

[oragex]

I don't think mine has a problem, but I've once shifted in R while driving on highway (just for a second I had a manual gear reflex). The car did nothing, not even slow down, and keep driving like it was in D gear. So I shifted back to D properly.

[jbeebo]

thanks for the response. So if I understand correctly, the interlock solenoid does not prevent shifting from drive to reverse while on the highway. Instead the 2 protection measures are the button on the shifter and the TCM being smart enough to not engage reverse if the car is moving forward above some speed.

In other words, my car's shift interlock system is working normally?

[jbeebo]

An update, for posterity's sake. Replaced the shift knob with OEM 8698157 ($95). Problem solved.

Here's how the shift interlock system on a 2005 S60 auto trans is supposed to work. If no comments beside the transition it means the brake pedal and shift button are irrelevant and not needed, you can execute the action just by pushing the shifter in the direction indicated.

Pulling the shifter down / rearward:
P -> R. Key needs to be in position 2. Brake pedal depressed. Shift button depressed.
R -> N
N -> D
D -> 4. Must depress shift button
4 -> 3. Must depress shift button
3 -> 2. Must depress shift button
2 -> L. Must depress shift button

Going the other direction, pushing the shifter up / forward:
L -> 2
2 -> 3
3 -> 4
4 -> D
D -> N
N -> R. Must depress shift button
R -> P. Must depress shift button

In other words, the shift interlock solenoid is only engaged and active in key position 2, in park, with the brake pedal depressed. All other shift positions the solenoid is de-energized / not active and plays no role in the shifter mechanism.

Hope this is useful in diagnosing issues with the solenoid and shifter