Transmission Codes: A Guide to Understanding Your Vehicle’s Transmission

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Have your check engine light come on, and unsure what it means? A transmission code could be the culprit. The sudden appearance of a transmission error code can be confusing and alarming. 

However, knowing how to read these codes can relieve us in this situation. Read on to learn more about common transmission error codes to get your car back up and running.

What are Transmission Codes?

Your vehicle is built-in with an Onboard Diagnostic System (OBD II) that monitors your car's systems while you drive. When your check engine light illuminates, there's something wrong with your car. 

To see what transmission code was set off, you'll need an OBD scanner. Simply plug the scan tool into the car's diagnostic port, and it will read the code. It will not be clear until you fix the problem.

Distinguishing the Types of Transmission Codes

When your vehicle detects a problem related to your transmission, your OBD scanner will show usually show one, but most of the time, more than one error code pops up.

So how can you distinguish these codes? 

The standard format of transmission codes is one letter and three numbers. For example, transmission code P0700. Let's discuss the corresponding meaning of the letters and numbers of this transmission code.

What does the First Letter Mean?

The first letter of the transmission code indicates the family of Diagnostic Trouble Code (DTC). The usual letter of the transmission code is P; however, some transmission codes start with different letters such as C, B, or U. These letters refer to

  • P: Powertrain (i.e., engine and gearbox)
  • C: Chassis
  • B: Body
  • U: User network

What does the Second Digit Mean?

A transmission code that starts with a 0 is a global transmission code, which means it can be detected by all cars. The transmission codes that begin with a number other than zero are manufacturer-specific transmission codes and will only appear in specific car models from the same brand or model.

  • 0: Global or generic
  • 1: Manufacturer fault

What does the Third Character Mean?

The third character in a transmission code is either a letter or a number identifying the vehicle subsystem with an issue.

  • 7, 8, and 9 - Transmission or gearbox-related codes
  • A, B, C - Hybrid propulsion codes

What do the Fourth and Fifth Number Mean?

The last two numbers in transmission codes are a little more specific. The fourth number is the gear with problems, while the fifth number indicates what type of problem it is. It could be 0 to 99.

To make it clearer, let's take an example. For instance, code P0010:

  • P is the transmission code, the first one is 0, and it says no transmission-related codes are found.
  • The second number, "0," indicates a transmission control system (TCS) or electronic transmission control system (ETCS).
  • The 1 means transmission gear one.
  • The last number, "0," means it's an electrical issue.

Classification of Transmission Codes

Transmission codes can be classified into transmission system codes and gearshift (transmission control) codes. The transmission system codes are the most serious of all transmission codes and indicate a fault in the transmission system.

Some standard transmission system codes are:

  • P0700: Transmission System Fault
  • P0894: Transmission Fluid Pressure Sensor Circuit Malfunction
  • P1706: Transmission Range Selector Switch Circuit Malfunction

The gearshift or transmission control codes, on the other hand, are not as serious as transmission system codes and usually indicate a problem with the gearshift or transmission control systems. 

These codes indicate faults in your car's transmission, such as wear and tear of parts, low transmission fluid levels, faulty sensors, or clutches. Some common gearshift transmission control codes are:

  • P0700 – This transmission code is caused by a transmission control system or clutch actuator circuits.
  • P0705 - Transmission Range Sensor Circuit Malfunction (PRNDL Input)
  • P0715 - Input/Turbine Speed Sensor Malfunction
  • P0720 - Output Speed Sensor Malfunction

Common Transmission Codes, Causes, and Symptoms

Transmission Fault Code



P0218 Transmission Over Temperature Condition

  • Damaged front air dam or spoiler
  • Damaged cooling fan clutch
  • Low transmission fluid
  • Torque converter seal leak
  • Dirt and debris in the transmission cooler
  • Restricted transmission lines or cooler

  • Slipping
  • Not enough heater
  • Too long to warm up
  • Faulty temperature gauge

P0700 - Transmission Control System (MIL Request)

  • Low or dirty transmission fluid
  • Faulty wiring
  • Failed TCM

  • Check engine light is on
  • Erratic shifting
  • The car only runs in two gears
  • Low fuel economy

P0701 Transmission Control System Range/Performance

  • Defective torque converter clutch
  • Faulty solenoid
  • Low transmission fluid
  • Faulty sensor
  • Broken wiring or connector
  • Slipping
  • Transmission is overheating
  • Leaking of transmission fluid
  • Check Engine Light is on
  • Rough shifting
  • Limp Mode

P0702 Transmission Control System Electrical

  • Failed torque converter
  • Failed shift solenoid
  • Low transmission fluid
  • Faulty sensor
  • Damage wiring

  • Transmission slipping
  • Difficulty when shifting
  • Engine stalling

P0613 - Transmission Control Module (TCM)

  • Transmission is overheating (common)
  • Low transmission fluid
  • Defective cooling fan
  • Faulty fluid sensor
  • Rough transmission when shifting
  • Harsh transmission shifting
  • Inaccurate or stuck speedometer/odometer

P0614 - ECM/TCM Incompatible

  • Replaced TCM or ECM
  • Not compatible ECM part replacement
  • Faulty PCM
  • Corrosion build-up at the connector
  • Short or open in the wiring harness

  • Not starting
  • Engine stalls
  • Rough transmission shift patterns
  • Inaccurate speedometer or odomete

P0706 - Transmission Range Sensor Circuit Range/Performance

  • Dirty transmission fluid
  • Defective park/neutral position switch
  • Faulty transmission range sensor

  • Check Engine is on
  • Erratic shifting
  • Decreased acceleration
  • Unable to switch gears
  • Poor fuel efficiency
  • Shorted wiring to the transmission range sensor
  • Damaged valve body
  • Limp mode

P0715 - Input/Turbine Speed Sensor Circuit Malfunction

  • Defective input/turbine speed sensor
  • Failed output speed sensor
  • Faultytorque converter
  • Damaged wiring
  • Restrictions or debris input/turbine speed sensor
  • Dirt on output speed sensor

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  • Check Engine Light illuminates
  • Fail-Safe
  • The engine has harsh shifting
  • The vehicle will not move
  • No power
  • Stuck in one gear

P0720 - Output Speed Sensor Circuit Malfunction

  • Faulty output shaft speed sensor
  • Open or short in the electrical wiring or connections
  • Malfunctioning PCM
  • Delayed shifting
  • Speedometer and cruise control malfunctions
  • Accompanied by P0715 or P0500 codes

P0750 - Shift Solenoid A Malfunction

  • Faulty shift solenoid A
  • Low transmission fluid level
  • Dirty transmission fluid
  • Solenoid A has a poor electrical connection
  • Faulty valve body assembly
  • The transmission will not shift
  • Delayed shifting from 1st to 2nd
  • Engine misfire
  • Poor fuel economy
  • Limp mode

Those are the common transmission codes that you may come across. But who knows, maybe your transmission is the exception and throws a code never seen before. 

In that case, you'll need to know some of the uncommon codes so you can understand what transmission problem you're dealing with. So, here's a list of transmission codes that are not so common:

  • P0751 Shift Solenoid A Performance or 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 or 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 or Stuck Off 
  • P0762 Shift Solenoid C Stuck On 
  • P0763 Shift Solenoid C Electrical 
  • P0764 Shift Solenoid C Intermittent 
  • P0765 Shift Solenoid D Malfunction 
  • P0766 Shift Solenoid D Performance or Stuck Off 
  • P0767 Shift Solenoid D Stuck On
  • P0768Shift Solenoid D Electrical
  • P0769 Shift Solenoid D Intermittent

As the transmission code doesn't only start with the letter P, transmission codes can start with B, C, and U. If your transmission has a problem, and you find one of these codes stored in its computer, it will be helpful to know what they mean. The following lists are some common transmission codes and their accompanying problems:

  • U1000 Cannot Communicate with TCM / Class 2 Communications Failure
  • U0101 Lost Communication with TCM
  • U0402 Invalid Data Received From Transmission Control Module

Transmission Codes FAQs

1. What does transmission code mean?

A transmission code is a diagnostic trouble code that can be stored by the transmission control unit (TCM). The transmission control module will store these codes and turn on the check engine light. This way, you'll know something is wrong with your transmission.

2. What is the code for bad transmission?

There is no universal code for a bad transmission. However, some of the most common transmission codes are U1000, U0101, and U0402. If you're experiencing problems with your transmission, it's best to take your car to a professional mechanic and diagnose the issue. 

3. How do you clear a transmission code?

Clearing transmission codes is a relatively simple process. You need to turn the ignition off and then back on again. This will reset the transmission control module and clear any stored codes.

4. How are transmission codes set?

Transmission codes are set when the transmission control module detects a fault in your transmission. Many different things can cause these faults, but they all have one thing in common: They're related to transmission problems.

5. What can I use to read the transmission codes?

There are a few different ways that you can read transmission codes. The best way is by using an OBD-II scanner. This scanner plugs into your car's diagnostic port and reads the transmission control module's transmission codes.


As you can see, there are many transmission codes, and each one means something different. If your car experiences a transmission error, it's important to read the code to identify the problem. By understanding these standard codes, you will be better equipped to handle this situation and get back on the road in no time. 

Have you ever had to deal with a transmission error code? What was the outcome? Let us know in the comments below.