What is Error Code P0700?

The error code P0700 is a diagnostic trouble code or DTC. It’s an informative code that indicates a possibility that the transmission control system is malfunctioning. The TCM or transmission control module works in monitoring the actuators and sensors that relate to the transmission control. It detects whether there is a malfunction in the control and then sends a signal to the ECM or “engine control module” to trigger the “Service Engine Soon” light or Engine light. The ECM signal, which stores the p0700 error code, means that the TCM has detected a malfunction in the transmission controls.


P0700 error code is a common diagnostic problem in several makes of cars. Below is some information that has been put together to assist you in the diagnostic and fixing procedures in the event that you car has error code P0700. The first thing you have to know about P0700 is that it is only an information code. This means that when it is set, there is not a direct fault that is indicated in the engine. Instead there is probably just a general fault.


There are many vehicles that have a control module for the automatic transmission called TCM or “transmission control module”. The TCM and ECM (engine control module) communicates with each other in monitoring whether there are faults in the automatic transmission. When the TCM detects a fault in the automatic transmission the transmission will set the appropriate code. At the same time, the ECM is informed as well which sets in its memory the error code P0700.

When error code P0700 is set, the MIL or “malfunction indicator lamp” illuminates in order to let the driver know of the problem. In that sense, if you can see that the code is present and at the same time the MIL is illuminated, then at least one transmission code has been set in the memory of TCM. Since P0700 is an informational code only and does not point to a direct fault, you will need more specific diagnosis to identify the main problem.

Common Symptoms

The most common symptoms of a P0700 DTC include the illumination of the MIL or malfunction indicator light. The most common cause are signs such as the transmission indicates problems in drivability like slipping. Other symptoms include decrease in the fuel, vehicle not shifting properly and some adverse conditions. In some cases, performance problems may exhibit such as misfire-like symptoms or dying when you are coming to a stop.

Possible Causes

Here are possible causes why your vehicle is signaling for error code P0700. It may be because one or more of these happened:

  • Some kind of transmission problem, the TCM detected it and set the code
  • Shift solenoids that are defective
  • Valve body that is defective
  • Malfunctioning engine coolant temperature sensor
  • Transmission fluid is dirty which restricts the passage of hydraulic
  • Faulty transmission control module, although that is highly unlikely

How to Check

When it comes to diagnosing P0700 DTC, recording of the information about freeze frame is important. Aside from recording, the code setting conditions has to be duplicated together with test drive. The thing is that P0700 is hard to detect, so you will have to pay close attention to engine load, RPM, throttle position and road speed

  • To diagnose if there is a fault to the transmission, the RPM input speed has to be monitored and compared to RPM output speed.
  • Monitor the response of the Converter Lockup Solenoid when the amount of throttle has been increased. It should go to 0 percent every time the brake pedal is applied no matter what the speed.
  • To find out if there is an internal slipping of transmission, see if the Slip Speed is steady but the transmission Output Shaft Speed is decreasing.
  • When the Slip Speed remains high but the Lockup duty cycle is still at 100 percent, the Solenoid is likely defective.

How to Fix

When the error code P0700 is present, the only real possible solution that you can take would be getting a scan tool in order to communicate with the vehicle’s transmission control module. It is not possible to take specific measures to fix any problem because P0700 is an informative code which means that it only indicates general fault. In order to find out a direct fault, comprehensive diagnostic procedure must be done in order to find the direct fault that has caused for P0700 DTC to appear.

On that accord, the very first step towards fixing the problem would be to extract the code from the TCM. On the other hand, if the scan tool does not communicate with the transmission control module, then it is very likely that the problem is with the TCM itself. In that case, it is the TCM that has to be repaired.

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