We know that diagnosing bad shift solenoids can be tricky, as they can basically turn your car into a rampaging bull that’ll have you bucking your head back and forth between shifts like any other transmission component gone cuckoo.
But luckily for you, we’ve gone and ridden this rodeo so many times in all sorts of vehicles already, and there are actually specific symptoms of a bad shift solenoid that people on their first rodeo may not be aware of.
As you read through all the common bad shift solenoid symptoms we’ve listed in this guide, you hopefully get to tame your transmission before it mistakes you for a matador again!
What are the common symptoms of a bad transmission shift solenoid?
Common symptoms of a bad transmission shift solenoid include a check engine light or check transmission light, delayed shifting, skipping gears, strange noises from the engine, and being stuck in one gear.
Other bad shift solenoid symptoms include transmission slipping and transmission fluid leaks.
Any kind of problem that concerns a vehicle’s transmission system can be a pain in the backside to figure out if you’re not that familiar with it, and that includes specific components like a shift solenoid.
But luckily, we’ve been wrenching on transmissions on vehicles of all shapes and sizes for years, so we’re all too familiar with the symptoms that a bad transmission shift solenoid can start showing.
And while we’ve already given you a list of such symptoms above, a general summary just wouldn’t cut it. Thus, let’s dive deeper into each of these symptoms that tell your shift solenoid is going bye-bye!
Check Engine Light Turns On
One of the first and most obvious signs that something is going wrong with your transmission shift solenoid can be found by simply looking at your dashboard or gauge, which is an illuminated check engine light.
Your vehicle’s check engine light (CEL) is triggered by the ECU (electronic control unit), or the brains of your vehicle, and it’s also responsible for monitoring various electronic components such as the shift solenoid.
The transmission shift solenoid, like many other electronically controlled components, operates under certain parameters. So if the ECU detects unusual readings from it, the check engine light will illuminate and error codes may be stored in the ECU.
Using a diagnostic tool like an OBD-II scanner, you can confirm that there’s an issue with the shift solenoid if you get a “P0750” code, which means “Shift Solenoid A Malfunction”, or the shift solenoid that’s responsible for shifting from 1st to 2nd gear.
In some instances, the check engine light may even be accompanied by a “P0700” code instead, which is a more generic code that means a malfunction has been detected in your transmission control system.
Check Transmission Light Turns On
Whenever there is an issue with the transmission shift solenoid or any other related component, certain vehicles may have their own separate “check transmission light” that illuminates rather than the check engine light.
Instead of a small engine symbol, a check transmission or transmission warning light is usually displayed as a small gear symbol with an exclamation mark or thermometer in the middle.
It acts basically the same way as the usual check engine light, except that it’s obviously only for problems concerning the transmission.
Of course, this means that the check transmission light can also be accompanied by error codes stored in the ECU, which means you have to connect the ECU to an OBD-II scanner or any similar diagnostic tool to read the codes.
Since there are multiple shift solenoids in an automatic transmission, there can be different kinds of error codes depending on which solenoid and what the nature of the problem is.
| Transmission Shift Solenoid Error Code | Description |
| P0750 | Shift Solenoid A Malfunction |
| P0751 | Shift Solenoid A Performance/Stuck Off |
| P0752 | Shift Solenoid A Stuck On |
| P0753 | Shift Solenoid A Electrical |
| P0754 | Shift Solenoid A Intermittent |
| P0755 | Shift Solenoid B Malfunction |
| P0756 | Shift Solenoid B Performance/Stuck Off |
| P0757 | Shift Solenoid B Stuck On |
| P0758 | Shift Solenoid B Electrical |
| P0759 | Shift Solenoid B Intermittent |
| P0760 | Shift Solenoid C Malfunction |
| P0761 | Shift Solenoid C Performance/Stuck Off |
Slow or Delayed Shifting
When your transmission shift solenoid is going bad, it can start to affect the performance of your transmission when shifting gears.
You can experience the transmission being slower or delayed when shifting up or down a gear, and this is because the shift solenoid is unable to open or close properly when needed.
The delayed shifts can allow the engine to rev up for a split second before dropping into the next gear, as the shift solenoid is unable to let the transmission shift smoothly at the right time.
As a result of this delay in shifting, gear shifts when accelerating or slowing down will start to feel rough and jerky, which affects the overall driving experience.
Transmission Skips Gears
Apart from lethargic gear shifts that can unintendedly make you headbang like a rockstar, a bad shift solenoid can just downright skip an entire gear.
As we’ve mentioned earlier, there are multiple shift solenoids (typically 2 to 5) in an automatic transmission, and each one of them is assigned different sets of gears that they are responsible for shifting.
If one of the shift solenoids becomes faulty or stops working, then transmission fluid will not be able to flow properly through the needed valves necessary to make the shift happen.
To give you an example, let’s use the table we used earlier as a reference. A malfunction with “Shift Solenoid A” would mean that there is something wrong with the shift solenoid for 1st gear and 2nd gear.
Similarly, a problem with “Shift Solenoid B” usually means that there is a problem with the shift solenoid that’s responsible for shifting between the 2nd gear and the 3rd gear.
Thus, if you’ve got a problem with Shift Solenoid B, then you may be able to shift from 1st to 2nd, but not 2nd to 3rd. The transmission may “skip” 3rd and go into 4th as a result.
Strange Noises from the Engine
It’s also worth listening to anything that sounds out of the ordinary from your engine when you’ve got issues with your transmission shift solenoid, as the engine is connected to the transmission, after all.
If you suddenly hear strange grinding noises along with some vibrations while driving, be sure to pull over to the side of the road and have your transmission system checked by a mechanic to properly narrow it down to a shift solenoid issue.
Depending on the situation and even the exact automatic transmission model, other strange sounds can also include whining, ticking, humming, or gurgling in specific gears.
Regardless of the sound description, any strange noises from the engine or transmission should not be ignored, as they can potentially worsen and turn into an even more expensive transmission repair bill.
Stuck in One Gear
Now that we’ve talked about the chances that your transmission can either shift too slowly or skip a gear with a bad shift solenoid, it’s also worth adding that you can even get stuck in just one gear.
We already know that the shift solenoid opens and closes every time you make a gear shift, but once it goes bad while a gear is engaged, then you may not be able to get out of that gear at all.
If you ever get stuck in a low gear, then you will not be able to travel at faster speeds past the limit of that gear.
In contrast, if you get stuck in a higher gear, you may be able to go faster, but you will not be able to downshift when it’s time to slow down.
At that point, you will fall out of the engine’s power band, making it difficult to raise the revs to accelerate optimally due to being stuck in a higher gear.
Overheating Transmission
Transmission fluid relies on the shift solenoids to distribute the essential cooling lubricant to various components during gear shifts, so if even one of the solenoids goes out, the transmission can potentially overheat.
If a shift solenoid is unable to provide adequate lubrication and cooling to a certain part of the transmission system, components can wear out faster and produce more heat, which can possibly damage surrounding parts in the process.
However, it’s also important to check the condition of your transmission fluid, as dirty or inadequate transmission fluid can also be the culprit to a bad shift solenoid, to begin with.
Automatic transmission fluid (ATF) typically needs to be changed every 30,000 miles (48,000 km), though this also depends on the vehicle model and type of ATF. We recommend checking the owner’s manual for your specific vehicle’s interval.
And of course, if you notice a strange burning smell coming from your gear shifter or the surrounding area, then that’s a strong indication that something has overheated in your transmission, so have it checked out at once.
Transmission Slips Out of Gear (Transmission Slipping)
A shift solenoid that has gone bad can also cause your transmission to slip or suddenly pop out of gear as you’re accelerating.
One common indication that your transmission is slipping is that the car’s engine seems to rev up yet you’re not really going any faster.
When it involves the shift solenoid, this means that it has failed to shift between gears properly, so you’ll be shifted back into neutral (N) instead. This explains why the engine is freely revving and you’re not moving, as no gear has been engaged.
Additionally, the shift solenoid may be able to keep the gear engaged, yet will struggle to engage or shift to other gears, just like the “slow or delayed” shifting issue we’ve discussed prior.
Thus, transmission slipping as a symptom can also be closely tied to jerky shifts due to the shift solenoid being unable to get the shift timing right.
Leaking Transmission Fluid
It’s also a good idea to have a look underneath your car for dark red puddles, as a bad transmission shift solenoid can also cause transmission fluid to leak from the valve body itself.
In these situations, one of the shift solenoids may have failed or gotten damaged, so it will not be able to seal and hold in transmission fluid that passes through it.
If not remedied immediately, the leak may result in low transmission fluid levels, which causes a cascade of other problems we already went over such as transmission overheating and slipping.
What is a shift solenoid?
A shift solenoid is an electronically controlled component that controls the flow of transmission fluid in an automatic transmission system.
The shift solenoid acts as a valve that opens or closes to let transmission fluid flow to certain components of the transmission system.
What does a transmission shift solenoid do?
The transmission shift solenoid controls the flow of transmission fluid throughout an automatic transmission system when shifting gears or performing other related functions.
How a Shift Solenoid Works
The transmission shift solenoid is controlled by the vehicle’s computer (ECU) and TCM (transmission control module), which sends electrical currents to the shift solenoid to either open or close depending on the needs of the transmission.
A transmission shift solenoid contains what’s called a “plunger” that is loaded with a spring. This spring is then activated via a coil of wire that receives signals from both the onboard computer (ECU) and the transmission control module (TCM).
During gear shifts, the plunger receives signals from the ECU or TCM, which tells it to open up to let transmission fluid flow through the valve body and apply hydraulic pressure to the necessary clutch packs and bands.
Once these clutch packs and bands receive hydraulic pressure, this is where the mechanical process of shifting between gears actually occurs within the transmission.
There are multiple shift solenoids (referred to as a “pack”) in a typical automatic transmission, and each solenoid is responsible for shifting between specific gears.
Depending on factors like speed, driving conditions, and fuel efficiency, the ECU or TCM will shift to what it thinks is the most appropriate gear to be in via any of the shift solenoids.
Though if one of these shift solenoids becomes faulty, then the performance of the rest of the transmission system can also become affected, as there would be an incorrect flow of transmission fluid.
What causes a shift solenoid to go bad?
A transmission shift solenoid can go bad due to natural wear and tear, low transmission fluid levels, dirty or contaminated transmission fluid, and different electrical issues.
If your vehicle equipped with an automatic transmission is an older model that has already accumulated over 100,000 miles, then chances are that your shift solenoid can be already worn out.
While shift solenoids aren’t assigned an expected lifespan from production, they have still been observed to last anywhere between 50,000 to 100,000 miles on average.
However, your shift solenoid can suddenly go bad a lot earlier for other reasons, two of the most common ones being either having dirty transmission fluid or low transmission fluid levels.
Dirty transmission fluid can clog the shift solenoid and prevent it from opening or closing properly, while low transmission fluid levels can increase the risk of overheating, which also causes damage to the shift solenoid.
This is why we can’t stress enough how important it is to follow the recommended maintenance intervals for your specific vehicle, and that includes replacing your automatic transmission fluid (ATF).
Transmission fluid aside, shift solenoids can also become faulty due to issues with your electrical system. This is to nobody’s surprise, as a shift solenoid is an electronically controlled component, after all.
Hence, be sure to take your vehicle to a mechanic as soon as you notice any of the common symptoms of a bad shift solenoid we’ve listed above. Otherwise, you risk damaging your transmission even further.
How to Diagnose a Shift Solenoid Problem
In order to diagnose a problem with the shift solenoid, you need to use a diagnostic tool like an OBD-II scanner to detect the presence of error codes in your ECU.
The error codes can tell you whether it’s really a shift solenoid issue or an issue that involves another component.
How to Diagnose/Troubleshoot a Shift Solenoid Problem:
1. Look for a wiring diagram for your specific vehicle model’s transmission.
2. Locate the exact pins that connect to the bad/faulty shift solenoid.
3. Remove the wiring plug from the transmission.
4. Using an OBD-II scanner or any similar diagnostic tool, do an output test on the faulty shift solenoid.
5. Using a voltmeter or multimeter, check if you can get 12 volts and ground to the shift solenoid via its exact pin on the wiring plug.
6. Getting 12 volts and ground while still having the same error code is an indication that you may have a bad shift solenoid.
7. If you neither get 12 volts nor any ground, then there may be a problem with either your transmission control module (TCM) or the wiring system instead.
Properly diagnosing a problem with your transmission shift solenoid can prove tricky at first, as the symptoms that it tends to show can be similar to that of other issues with the transmission system.
But this is where technology comes as a big help. By using diagnostic tools such as an OBD-II scanner, you will be able to detect any error codes stored in your vehicle’s computer or “ECU”.
Any error codes that show up on the scanner will have their own description, allowing you to distinguish if the problem really lies with the shift solenoid or not.
Furthermore, the error code can even tell you which specific shift solenoid it is as well as the kind of problem. For instance, getting a “P0752” code means that “Shift Solenoid A” is stuck in the “ON” position.
Shift Solenoid Replacement Cost
Replacing a transmission shift solenoid will cost around $300 to $500 in total depending on the vehicle and brand. Parts costs range from $200 to $400 while labor costs range from $50 to $100.
Replacing an entire shift solenoid pack will cost about $400 to $700 in total for both parts and labor.
How to Prevent Shift Solenoid Failure
To prevent shift solenoid failure, be sure to change your automatic transmission fluid (ATF) at the recommended intervals, as dirty or low transmission fluids are one of the most common reasons why shift solenoids fail.
In addition, cars that have a transmission cooler will also need maintenance for that part, as any issues with the cooler can overheat the transmission fluid and result in shift solenoid failure.
Frequently Asked Questions (FAQs)
