If you’ve been driving a car with automatic transmission, you must be familiar with the term “shift interlock solenoid.” But do you know what it is and how it functions and tell if it goes bad?
A few telltale signs indicate that your car’s shift interlock solenoid is bad. One sign is that your car won’t shift out of the park, even when you press the accelerator pedal. Another sign is that your engine will stall when you shift gears.
If you’re experiencing any of these symptoms, it’s time to replace your shift interlock solenoid. You can do this yourself or have a mechanic do it for you. For more information, read on!
7 Signs That Your Shift Interlock Solenoid Is Bad
Your shift interlock solenoid is a critical piece of your car’s transmission. If it is bad, it can cause all sorts of problems. So, here are seven signs that you may need to replace your solenoid.
Warning Lights
If you have a warning light that goes off on your dashboard or flashes, it’s essential to investigate the problem. Many warning lights can be related to various systems in your car. However, one warning light connects to your Shift Interlock Solenoid.
You should know that this warning light displays “Shift Lock Solenoid” or “Park Shift Interlock.” It usually goes off when you push down your brake pedal, and your car doesn’t respond. Some vehicles will display the message “shift lock solenoid open,” indicating a problem with the solenoid.
Difficulty Shifting
If you have difficulty shifting gears, the chances are that the Shifter Interlock Solenoid is bad. If your car comes to a grinding halt or it jerks as you change gears, then something might be wrong with the solenoid.
While this symptom isn’t always due to a bad shift interlock solenoid, it’s definitely possible. Luckily, most modern cars come with diagnostic tests to determine the problem.
Difficulty Starting
One of the signs of a bad solenoid is having difficulty starting your car in general. If you turn the key and hear nothing but a click before turning your car right back off again, then it’s likely there’s something wrong with the solenoid.
When you put up a fight to start your car, it could signify a more significant problem. It may be a bad solenoid or, worse yet, a dead battery.
No Response From the Brake
If you have trouble moving the stick from the park to any other gear, then there might be a problem with your solenoid.
In cases where the car will not move out of the park, this commonly results in pushing down on the brakes without any resistance. It’s likely that your shift lock solenoid is stuck and needs immediate attention if you want to keep driving your car.
No Acceleration
Perhaps one of the more frustrating symptoms of a bad Shift Interlock Solenoid is that nothing happens when you press down on the gas pedal. When you push hard on that gas pedal, and it doesn’t even make a peep before returning to its original position, there’s a chance that your car isn’t getting the right amount of power.
Usually, this means something is wrong with how your car transmits or receives power–but not always. You might want to take it to a mechanic and let them perform some tests on your vehicle just to be sure.
No Exterior Lighting
If you’ve noticed that all of your exterior brake lights suddenly stopped working, then there may be an issue with the Shift Interlock Solenoid. This solenoid controls the locks and other safety systems within your car, which allow you to lock/unlock doors/windows and turn the lights on and off remotely.
If the lights on your car are flashing at random times, this means that there’s an electrical issue somewhere within your car’s systems.
No Interior Lighting
Just like with exterior lighting, if you notice that one or more of your interior lights stop working, it might be because of a faulty shift lock solenoid. This could also mean something is wrong with the electrical wiring throughout your system. But, it could also mean there’s a problem with the Shift Interlock Solenoid itself.
Suppose you notice any malfunctioning or strange behavior with your car’s lights. In that case, this usually means that something is wrong and requires attention as soon as possible to avoid further damage and accidents.
Check Out How Do I Know if my Shift Interlock Solenoid is Bad:
What Is A Shift Interlock Solenoid?
A shift interlock solenoid is a part of your automatic transmission that engages the top gear inside the transmission. This solenoid only allows the car to move forward, and therefore it must be engaged to allow you to drive. In some cases, this shift interlock solenoid can fail to cause it not to engage, making it impossible for you to shift from the park into any other gear.
For you to successfully test this solenoid yourself, all you need is a multimeter and an assistant to help guide your car onto a flat surface. First, you will want to check if the shift interlock solenoid itself is getting power by testing across two terminals on its connector with one lead of your multimeter. If you are getting voltage, then the shift interlock solenoid is good.
The next step will be to check if the switch that controls the shifter console works by jumping across terminals on its connector. You will want your assistant to try and move the shifter while you monitor for movement with your multimeter. If it tests fine, there is a problem with your transmission or the wiring between the two components.
If this test shows that you have issues somewhere between these components or that one isn’t putting out voltage, then it’s time for you to call a professional!
What Does A Shift Interlock Solenoid Do?
This solenoid is part of the shift interlock system, which prevents you from taking your car out of park unless you’ve your seat belt on. If the shift interlock system detects that you’re not wearing a seat belt, it electronically immobilizes the car until you buckle up.
If this solenoid malfunctions, the shift interlock system will stay engaged, and you won’t be able to take the car out of park until you fix it.
Why Is My Gear Shift Stuck?
The reason you can’t get your car in gear could be one of the following.
- The engine is not running. If you’re sure it’s neutral, try turning the key to start and see if that does it. You should hear a clicking or grinding noise if this is your problem because the starter solenoid is jammed.
- The shift linkage might be bent or jammed. A visual inspection should determine this, but it usually shows up by having difficulty engaging Drive or Reverse. If it gets jammed, the car will stop.
- The brake/clutch pedal interlock might be faulty and let you shift out of the park without actually applying the brakes (this also usually shows up by having difficulty engaging Drive or Reverse).
- Your transmission could be failing (the fluid is probably dark).
How To Fix A Stuck Gear Shifter?
If you’re driving and your gearshift becomes stuck, don’t panic! Here is a thorough tutorial you can follow to fix the issue.
- The first thing you need to do is remove your key from the ignition if possible. If it’s sticking or difficult, remove any other J-shaped hooks inside the car that may hold the key in place. If your vehicle does not have these, you can just skip this step.
- Next, you need to open the hood of your car. There should be a latch for this in the front area of the engine compartment.
- Open it up and make sure that the hood is secure! If there are small doors at either side hinge-point of your hood, open these too, even if it’s not letting you open the hood entirely.
- You need to disconnect your battery. Positive first, then Negative, but it doesn’t matter which order but do both anyways. It will prevent any accidents while you’re working on fixing this issue afterward.
- Like most cars, if your battery is in one connector, use a wrench to disconnect it.
- However, for a plastic strap over the top of your battery holding it in place, use a small screwdriver or a butter knife. Then, lift one side and slide out the metal connector underneath.
- Now, you can open up your gear shift. There will be two screws holding the paneling over the gears in place in most cases – remove these carefully as they are most likely rusty. You may need pliers or another tool depending on the rust.
- Once you have removed both screws, pull back the rubberized sealing covering around where your gear shift is inside your vehicle. Now you will see the back of your gear shifter.
- Now, take a butter knife or flat tool and gently pry around the edges until your shifter starts to move. Keep trying this until you’re able to open up the shifter cover completely.
- Once it’s open, look inside the shifter. Do you see something that looks like toothpaste squished in between two gears? This is what has likely caused your shifter to get stuck.
- Take some WD-40 and spray some on each of these areas where this jammed goo is.
- Leave some overnight if possible but at least for an hour or two so that it can break apart whatever was causing it to be stuck previously.
- After doing this, put your shifter cover back into place and see if it is working correctly.
If you are still having issues with your shifter being stuck in a position, try to spray more WD-40 around the edges of the cover until it starts sliding again. If you can’t even get this far, there may be an issue that these simple steps cannot fix.
Diagnosing A Shift Solenoid Problem
You might notice several symptoms if your car has a shift solenoid problem. The first may be that it won’t shift at all. There will either be a knock or thump as the transmission engages if it does. Either way, don’t ignore it!
Another symptom you might see is that your car just won’t go into gear, and you press the gas, and nothing happens. If you notice this, stop driving the vehicle immediately and call a tow truck to get it towed in for servicing.
It’s better not to drive any further than you have to because continuing to drive after something like this has happened may cause more damage or even destroy your transmission if left too long without repair.
If you notice your lights starting to dim when shifting gears, this could also be an indicator of a shift solenoid problem. To be sure, a qualified mechanic can check your transmission fluid level to diagnose a shift solenoid issue.
Moreover, you can use a free diagnosis check engine lights yourself without even leaving home. One way would be downloading an OBD2 app on your phone or tablet to access the sensors inside your car. Then, using a code scanner designed for vehicles, you can read live data of what is going on with your car.
All OBD2 scanners have a series of protocols to connect with the chips and sensors. A list of these protocols can be found online and downloaded into your scan tool. While not necessary, it will help you find the best way for different makes and models to communicate with each other.
Standard Trouble Codes For Shift Interlock Solenoid
An automotive trouble code is a numbered code given to a detected malfunction in a motor vehicle’s engine or emissions control system. People also call these diagnostic trouble codes “DTCs.”
Plus, technicians and engineers use them to identify and address the car’s computerized engine management and drivetrain systems.
The most common trouble codes for shift interlock solenoids include P0700, P0715, U1028, and U1041.
P0700
This trouble code is one of the most common for shift interlock solenoids. If you are getting this, it’s likely because the brake pedal position switch has failed or is malfunctioning. This will continuously signal the shift lock control module, which tells your ignition key cylinder to remain unlocked.
You may also notice that your starter will crank but not turn over. It can also cause your anti-theft system to engage by disallowing the engine from starting.
P0715
This trouble code specifies an error with the shift lock control module. It detects there were no changes within 15 seconds after entering into program mode, either opening or closing a door. Neither, by pressing and holding the UNLOCK button on the RKE transmitter.
If this fails to be corrected, you will receive a “shift lock control system malfunction.” An issue usually causes this with either the wire harness or the internal part of the shift lock control module.
U1028
The code U1028 is for open transmission range circuits. This means there could be an issue with your ignition switch, wiring, PCM, body control module (BCM), battery cables, etc. You would get this trouble code because it’s likely that there was no voltage detected within 30 seconds of entering program mode.
Since the key cylinder needs power from your car battery to enter program mode, this can cause an issue with the ignition lock cylinder turning the key. If you see this, it’s better to have your battery cables checked.
U1041
This code specifies an error with the transmission range sensor circuit with no voltage within 30 seconds after entering program mode.
Your vehicle will also give another code, U1065, once they both fail. This trouble code deals with entering program mode without any voltage, which may be due to loose wiring or failing PCM. You’ll want to check your PCM for damage or replace it.
If you are getting any of these trouble codes, you should have a mechanic look at your vehicle. If the shift interlock solenoid has given out, having this replaced will usually resolve all issues related to not starting your car.
When and How to Replace Shift Interlock Solenoid?
Several warning signs indicate the replacement of the interlock solenoid that you should watch out for.
- The “Check Engine” light comes on and stays on when there isn’t any problem with the car’s emissions system. Automatic transmissions need electrical voltage at all times to avoid damage. So, a faulty shift interlock solenoid can also affect other systems like airbags and power windows.
- The car rolls forward or backward while in the park. It can happen if you release the brake with the shifter in “P” for the park, it can happen. If you’re parking your car on a hill, this can cause an accident, so have it checked if this happens to you.
- You turn off the engine, but the “Check Engine” light stays on. If you experience this, get your automatic transmission looked at immediately because of its relation to safety features like airbags and antilock brakes that are part of your car’s computer system too.
How To Replace It?
Replacing a broken shift interlock solenoid is a pretty simple task, especially if you’ve done it before. You can usually get this done in less than an hour, and the only tools you need are a torque wrench and a Phillips-head screwdriver.
If you are experiencing difficulty shifting your automatic transmission from the park into any other gear, you should do it. If you have been having issues with your shift lock solenoid, follow the steps below to resolve it.
NOTE: There are many different transmissions available in today’s modern cars. Many have similar designs and use nearly identical components to interlock solenoids. You must use the steps below as a general guideline only.
Step 1
Park your vehicle on level ground and engage the emergency brake. Then, turn off your car’s ignition (and all accessories) and set the parking brake.
Step 2
Remove both of your car’s front side doors, then disconnect the negative terminal cable from the (-) battery post with an open-end wrench or socket wrench before touching anything else inside your vehicle with exposed metal surfaces (such as screwdrivers and wrenches).
This is important because it prevents you from accidentally short-circuiting any electrical components while performing this procedure.
Step 3
Next, remove the black rubber dust boots that surround your car’s shifter cables by prying them off with a flathead screwdriver.
Step 4
Remove the cotter pin where it attaches to your shifter arm using needle-nose pliers or cutters. Now, pull the shifter cable/arm assembly down and out of its mounting brackets on both sides.
Step 5
Locate your vehicle’s shift interlock solenoid connector at the front center of your transmission – just beneath the fuse box. Remove it by turning it counterclockwise with an open-end wrench. You will see two wires attached to this terminal post, but ignore those for now as they are not involved in this replacement procedure.
Step 6
Next, locate the shifter cable mounting brackets on both sides of your car’s transmission. These should look like small metal tubes and sit directly beside (or slightly above) where you removed the shifter cables in Step 4.
Now, use a flathead screwdriver to pry each bracket away from its mounting posts on either side one at a time – this will allow you to remove the entire shifter cable/arm assembly as an individual unit.
Step 7
Locate (and remove) the six screws that hold your vehicle’s transmission cover plate in place (two screws per corner). These screws may vary between vehicles, but they are typically around the perimeter of where you just removed that shifter arm/cable assembly.
Step 8
There are many different vehicles out there, so we can’t tell you exactly how to remove your car’s transmission cover plate. This will be up to you and your manual of choice.
However, the following steps require that you have removed your cover plate. If not, go back and do it now. Also, make sure that you have enough space inside the engine bay to work comfortably.
Step 9
Two small yellow caps sat mid-way down on either side of the transmission. These are drain plugs for releasing old fluid from your car’s automatic gearbox. This is where having a pan or bucket comes in handy for catching old fluid).
Step 10
Re-install these drain plugs before removing your car’s transmission filter by turning them clockwise until tight.
Step 11
Next, locate the four bolts that attach your car’s gearbox to its lower mounts (two on either side). These are typically just above where the two yellow caps were in Step 9. Now, remove each bolt with an open-end or socket wrench while holding the nut adjacent to it with a second wrench.
When finished, pull your transmission away from its mounting brackets so that you can see underneath it and ultimately expose the shift interlock solenoid you removed in step 5.
Step 12
Locate the connector on top of your shift interlock solenoid. There should only be one in this location, regardless of whether or not you have an electronic or cable shifter.
Once located, use a flathead screwdriver to pry off the black plastic dust cover surrounding the wire terminal posts (you will see six individual terminals when exposed).
Now, pinch each wire’s metal terminal end with needle-nose pliers and pull them out one at a time until they are all removed from their respective slots.
Step 13
Next, locate your new shift interlock solenoid, which should come with two sets of wires attached to it already – if so, ignore this step.
Step 14
Locate the wire terminals you removed from the old solenoid and match each with a corresponding terminal on your new solenoid. When attached, these wires should resemble a male/female plug with a small tab somewhere along their length.
Step 15
Now, insert each wire into its respective slot on the shift interlock solenoid until they are tight to avoid loose during vehicle operation. An easy way of doing this is by using needle-nose pliers while pushing against the wire’s outer sheath (not too hard).
Ensure that individual wires don’t touch or short-circuit against each other when inserted into the correct slots.
Step 16
Once finished, re-attach the black plastic dust cover to its original position by placing each wire’s terminal end through its respective slot until it clicks. Then, spread a protective light coating of grease over the exposed metal terminals to avoid a loss of electrical connection during vehicle operation.
Step 17
Re-install your new shift interlock solenoid into its original location and use a flathead screwdriver to tighten each bolt that secures it in place (do not fully tighten yet).
Step 18
Next, install your car’s transmission filter back onto its lower mounts using two open-end wrenches or socket wrenches. Be sure not to overtighten these bolts/nuts, as this will crack your filter’s casing.
Once tight, re-install your car’s drain plugs by hand and tighten down both caps onto each one using a screwdriver or ratchet set to the correct torque setting (do NOT overtighten these – just turn until they feel snug).
Step 19
Now reinstall your car’s transmission and secure it in place with its four bolts (two on either side) by turning them clockwise until tight. Next, reinstall any remaining filters and hoses you removed from your engine bay during this procedure.
Check Out How To Replace Shift Interlock Solenoid:
Used or Remanufactured Transmission: Which is Better?
Many people use the words “used” and “remanufactured” interchangeably, but they aren’t the same thing. Here are some distinctions between these two kinds of transmissions:
Used Transmission
A used transmission has previous wear on it because it was in another car previously. The previous owner might have traded their car in for a newer model, fixed their transmission after it broke down, or simply decided to buy a new vehicle. Either way, if you’re buying this type of transmission, you’re getting someone else’s old car part that’s taken off the car.
Sometimes the person who had this kind of transmission before will sell it to you without the year, make, and model of the car it came from. If you buy a used transmission from this type of seller, you might not even get the same year, make, and model as advertised.
Remanufactured Transmission
A remanufactured transmission is thoroughly taken apart, inspected for damage or faulty parts, then put back together with new parts. It has all-new everything inside of it ─ gaskets, seals, bearings. All of this may still look pretty good to someone who doesn’t know much about transmissions.
You might not know for sure if it’s actually brand new unless you’re buying this type of transmission from a dealer or other supplier. They can certify to you what year, make, and model the parts came from.
Also, unless you get your remanufactured transmission from a place with the same name on the warranty as the previous owner’s name, there is no warranty to keep you safe in case anything goes wrong after installation.
So which type of transmission should you buy? Well, it depends on how much money you have to spend. A used transmission would be cheaper than a remanufactured one because it doesn’t have any warranties.
On the other hand, if you want something that has no previous use and all-new parts (and maybe it even comes with a warranty), then you might as well go for a new one. It won’t cost much more than an equally equipped used car.
Cost of Repairing Shift Interlock Solenoid
As of 2007, there are an estimated 6 million cars on the road in the US with a faulty solenoid. The following is a real-world quote for how much it is to repair this issue.
Repair Cost
You can troubleshoot and potentially fix the interlock solenoid with the used transmission, approximately $2200 plus tax.
The national average for repairing shift interlock solenoids is $1,097, and this price can vary from around $800 to around $3,000.
Replacement Cost
The replacement cost for Manual Transaxle 1.8L 1998 Ford Escort 1 is mostly around $100+. But, it may be more depending on what other things are wrong with the car, which you should find out beforehand if possible. Commonly, the replacement cost for this part on a vehicle is approximately $65.
FAQs
What Location Is The Shift Interlock Solenoid In?
It is typically on the transmission side (the right for FWD applications). The exact location will vary depending on make and model, but there are some common locations though:
– On the right side of the transmission
– On the top right of the transmission (drivers side)
– On the driver’s side at the front, close to where you would expect a dipstick to be.
Will a malfunctioning shift solenoid always generate a code?
No, it depends on the ELD and its design to handle faults. Often, a shift solenoid may be bad but will not always throw a code, especially when carbon badly clogs it.
What is the purpose of a shift interlock actuator?
The shift interlock actuator (also known as a transmission range switch) tells the vehicle’s computer if the shifter is in park, neutral position, reverse or drive.
This prevents you from moving the gear shift out of the park unless your foot is on the brake pedal. If it fails, your car may not start, or you could be able to remove the key from the ignition without shifting out of the park.
Shift To Park: What Does It Mean?
A shift to park, also commonly called a gear to park or simply put in the park, refers to shifting an automatic transmission into the position that locks the car’s wheels. This automatically engages the car’s parking brake, preventing the vehicle from moving as long as the engine runs.
With a manual transmission, you simply pull up on the handbrake shifter lever and let go to engage it. You have to put it into a specific gear that engages the parking brake with an automatic transmission.
The shift to park position usually has an indicator on the dash that says “P” or some variant. It indicates that the gear is in the park, and the parking brake is engaged.
On newer cars with automatic transmissions, you also need to keep your foot on the brake pedal while shifting into the park because unless you do this, the shift-to-park function won’t work.
Final Consideration
If you’ve problems with your gear shifter and nothing happens when you move the lever, the chances are that it’s a bad shift solenoid. And to resolve this issue, you can pay heed to the 7 signs mentioned above.
Also, now you know how to diagnose potential problems and the standard trouble codes associated with this component. We hope we’ve answered all of your questions so far!
But if there’s anything else, you can go to an automotive repair or maintenance workshop to get your concerns addressed.
