P0700 – Transmission Control System Malfunction

The code P0700 is set when the vehicle’s computer notices a malfunction in the transmission control system. In most cases, this will cause a Check Engine Light to pop up on your dashboard and the vehicle might stop shifting properly.

It’s also common for P0700 to show up alongside other transmission codes, so make sure to review them all to get an idea of what’s really going on.

You don’t want to ignore this code, as it will put the vehicle in a “fail-safe” mode, making it difficult to drive. The vehicle will remain in this fail-safe mode until the problem has been addressed and the code is cleared.


This code is thrown because something is wrong with the transmission, either mechanically or electrically. Wiring harness issues are a common culprit, but sometimes it’s the transmission control module.

  • Damaged wiring
  • Problems with the shift solenoid
  • Bad transmission control module
  • Faulty transmission valve body
  • Driving while low on transmission fluid
  • Failed speed sensors
  • Converter clutch
  • Faulty engine coolant sensor


  • Check Engine Light will usually pop up on dashboard
  • Poor gas mileage
  • Transmission not shifting properly
  • Engine stalls / runs poorly

How to Fix P0700

Most mechanics will start by scanning the vehicle and checking for all the present codes, as this will allow them to see if other transmission codes are set. P0700 is usually not the only transmission code you will find, but if it is then that might be a good sign.

Using a good scanner, the mechanic will check the freeze frame data to see what was going on when the code was set by the computer. The information provided will help to diagnosis the issue and fix the source of the problem.

By this point, any good technician will clear the code and take the vehicle for a test drive to see if they can make it pop up again. It’s also worth noting that a scanner will be hooked up during the test drive so the mechanic can check the live data and check for anything out of the ordinary.

Now, the mechanic will inspect the wiring harnesses going to the transmission and check for any damages. Fortunately, a good scan tool will allow you to monitor the solenoid operation and condition of the valve body.

Common ways to fix P0700 include:

  • Replacing the transmission control module
  • Repairing or replacing wiring
  • Replacing the valve body
  • Replacing the shift solenoid

Sometimes, the problem is as simple as low transmission fluid. But there are also times when the transmission needs to be replaced entirely.