It's not uncommon for Jeep owners to see a very strange and misleading message saying "Service Transmission. Restart in Park with Vehicle in Zero Speed". When you are reading this, you may be sure that the problem is with the transmission - one of the most expensive units in your car. Also, the car won't start when you see this message.
If your Jeep shows this message, you most likely have one of three possible issues: a dying 12V battery, oxidized ground cable, or broken TCM (transmission control module). This may happen to many Jeep models but it is notorious for the 2014-2018 Jeep Cherokee.
Restart in park with vehicle in zero speed message highlights
- Common reasons:shifter cable, shifter, transmission issues
- How to fix:check if cable moves when you shift, inspect the transmission
- Possible consequences:this may leave you stranded
- Priority level:High
- Can you drive?Usually no
- DIY repair:Impossible
- Repair price range:$500-$5,000
Let's see what you can do with this!
The common reasons for the transmission error
The second part of the message says that you should restart in Park with the vehicle at zero speed. So, it means that your Jeep basically thinks your car is rolling and the transmission is not in Park. The safety features in the TCM are triggered and the vehicle can't be started.
Sometimes, you can solve it by turning on the accessory mode and trying to put the shifter in different modes (D, N, etc.) before putting it back in Park. But this will only help if the problem is minor.
Here are the reasons for this issue and ways to fix them:
1) Low 12V battery
Usually, this message will pop up when you are trying to start your Jeep. In this case, the battery will try to power all the needed units but it may fail to do that if the voltage is low. When the voltage in the system is low, almost any unit can malfunction. So, random error messages may start popping up on the dash and bothering you.
Checking the battery with the multimeter is pretty hard because it will show 12+ volts even when almost dead. So, you may decide to jump the battery or charge it to make sure it isn't the actual reason for the problem.
2) The ground cable
While it's worth checking all the ground connections when you get this issue, there is one specific ground strap that you should check in the first place. It's located behind the plastic wheel well liner on the driver's side. The strap is not protected by any isolation and it's located right under the screen washer reservoir. So, some screen washer fluid may get onto it and cause bad oxidation.
If you are stranded, just check this ground strap and maybe try cleaning the connections. If nothing helps and the strap looks heavily oxidized, you may just need a new one. The price is about $20-30 and you can clearly replace it on your own.
3) The TCM problem
There were several recalls for the 2014-2018 Jeep Cherokee connected with the control modules. The TCM recall allowed the dealers to replace the TCM in affected vehicles with zero charges for car owners.
You should check the VIN of your car at the NHTSA site to find out if your vehicle is eligible for this recall. If not, you will still need to check the TCM because it may throw this kind of message in your vehicle.
Unfortunately, checking the TCM is not that easy, so I recommend going to the dealer for this. Of course, your car will have to be towed because it won't start. But before you do that, you should try all the possible DIY repairs that are listed in this article.
What to do before going to the dealer?
So, now you know the most common reasons for this Service Transmission message in your Jeep. And before you opt to go to the dealership, pay for towing, and also pay for repairs and inspections, I suggest you should try the following:
- disconnect the battery to reset the control modules in your Jeep;
- if this doesn't help, charge or jump the battery to make sure it's not low;
- check or maybe even just replace the potentially faulty ground strap under the wheel well liner on the driver's side;
- try reading the codes with the scanner and see what is happening with your car.
If nothing helps, you will most likely need professional help to diagnose the TCM and probably replace it with a new one. Also, after the TCM replacement, your Jeep will need some reprogramming in the dealership.
About the authors
The CarAraC research team is composed of seasoned auto mechanics and automotive industry professionals, including individuals with advanced degrees and certifications in their field. Our team members boast prestigious credentials, reflecting their extensive knowledge and skills. These qualifications include: IMI: Institute of the Motor Industry, ASE-Certified Master Automobile Technicians; Coventry University, Graduate of MA in Automotive Journalism; Politecnico di Torino, Italy, MS Automotive Engineering; Ss. Cyril and Methodius University in Skopje, Mechanical University in Skopje; TOC Automotive College; DHA Suffa University, Department of Mechanical Engineering
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