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I’m occasionally having problems with my ’07 Chevy Cobalt (with automatic transmission) where it will get stuck in Park. When I press the release button on the gear shift, a loud click is audible from beneath the steering column, and it remains locked in Park as if I had forgotten to press the brakes. When it works correctly, I don’t hear the same click (there may be a softer click but it’s hard to tell if it isn’t just the physical click of the release button).

Once, while the gear shift was working, I also noticed that when I shifted back into Park, the car doors didn’t automatically unlock as they usually do. At another point in time, they did unlock, but with an unusual delay.

Searching for this finds a lot of questions about people with similar symptoms, but who also cannot remove their key from the ignition. I have never experienced that. Since this seems to be related to the feature that prevents you from moving out of Park without your foot on the brakes, I checked and determined that the brake lights do work correctly when the brake pedal is pressed.

Searching also suggests—but I’m not at all certain—that the culprit for the refusal to shift out of Park is likely the “shift interlock solenoid,” which is plugged in under the gear shift (and distinct, as I understand it, from the “shifter solenoid,” which is also attached to the gear shift and controls the actual shifting of gears, and has totally different symptoms when it starts to go). I haven’t been able to find good information about the auto-unlock feature, whether that’s more symptoms of the same problem or a symptom of some other problem. Also, the fact that the loud click seems to be coming from under the steering column rather than under the gear shift has me worried that the failure is actually in the solenoid that’s under there, instead. But my understanding is that if that were failing, the brake lights wouldn’t work, and they haven’t shown any trouble.

Unfortunately, the ’07 Cobalt does not have a shift interlock override, as many other (newer?) models do, so I can’t test if that’s the problem by using the override. The only advice in the manual about it is to take it to the dealer. This is a very old car that we’re trying to replace (and don’t expect much of anything in trade-in value anyway), so I really don’t want to invest more into this if I don’t have to.

So, does anyone know (or have strong, backed-up suspicions of) what’s causing this, whether that’s the shift interlock solenoid or something else? My assumption is the two problems are related but if that’s wrong, I’d definitely like to know (the shifting issue is far more serious than the auto-unlock). I’d also definitely appreciate pictures of the part I need, and instructions for doing the replacement (if it is reasonably user-serviceable, which the shift interlock solenoid appears to be), if that’d be possible.

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There are several safety features in our vehicles to prevent shifting an automatic and keeping the steering column locked. The shift lock is a solenoid to prevent shifting an automatic and requires pressing the brake pedal first to energize the park shift lock solenoid to allow shifting out of Park position when the engine's running. Engine off, ignition in ACC or ON, the shift lever can be moved out of Park position. There are two brake switches under the brake lever assembly. One switch is for the brake lights and cruise control. The other is for the Park shift solenoid. There's also a Park/Neutral safety switch to prevent starting in Reverse or Drive (D2, OD). Although designed for long term reliability, it's mounted on the transmission, this can wear out or become misaligned if work is performed on the xmission. You should not be able to start the engine in R or D. Only P and N are wired to allow starting the engine. The Park/Neutral safety switch prevents anyone from inadvertently starting an engine in Drive or Reverse whether applying the brake or not. If your shift lever is in the console, there should be a shift lock solenoid and tab that locks/unlocks the shift lever. It can be as simple as lifting up the shift boot with frame and moving the tab to one side to unlock the shift lever otherwise simply turning the ignition switch to ACC or ON without starting should allow moving the shift lever without pressing the brake pedal.

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    This is a vaguely-related infodump that doesn’t even necessarily apply to my car, since—as noted in the question—my car does not have a “tab” that can override the lock and release the shifter. This does not help me; answers need to interface with the actual question more, or else I could just ask my question of Google or ChatGPT and get about the same level of usefulness.
    – KRyan
    May 25, 2023 at 16:04
  • Well, if no one here has the expertise to give you an answer, then I suggest searching Chevy Cobalt forums. There may be experts there as well as possible GM techs willing to answer questions. I can understand your predicament and short of going to GM for repairs, online help are available as there are experts with help, free or fee. I know that my '03 GM/Saturn L300 has the park shift lock solenoid and tab in the console shift assembly that can be moved with a pencil or finger to release the shift lever.
    – F Dryer
    May 26, 2023 at 21:19

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