P0702: Transmission Control System Electrical OBD-II Trouble Code

If you are curious about the cause of a P0702 DTC (diagnostic trouble code) from your vehicle, the answer is very simple and very confusing depending on the vehicle’s drivability.

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The DTC P0702 – Transmission Control System – Electrical, simply means that something went wrong in the electrical system that controls the automatic transmission. It is a generic trouble code that every vehicle using OBD-II has in common.

There should always be another code stored in conjunction with P0702. That will be the key, solve that other problem and usually P0702 goes away.

The TCM monitors all of the actions electronically and mechanically of an automatic transmission. It analyzes several inputs from sensors, makes millisecond decisions, then controls several more outputs to hydraulic valves and solenoids and does all of this while keeping an eye on several more stats from the Engine Control Module (ECM).

How Serious is the P0702 Code?

The question is, how serious is the underlying condition that produced this code? The second code will provide more information on the cause of any problems. The second DTC can be from the TCM or ECM. If the vehicle is not experiencing any obvious drivability issues, the DTC may have been set from an anomaly or simply a discharged battery. If it is shifting hard or not at all, it may indicate catastrophic failure.

Taking note of any other symptoms will help with further diagnostics. Please note that if you have a manual transmission this code may not apply. It’s possible the vehicle had the ECM replaced and is using one that originally controlled an automatic transmission. Depending on make and model this may not even be possible.

Symptoms of P0702

Here are some common symptoms for P0702. Remember that your vehicle may experience some or none of these behaviors.

  • Check Engine Light illuminated
  • Traction Control Light illuminated
  • Abnormal shifting – revving higher than normal before shifting
  • Harsh shifting
  • Delayed response when changing gears
  • Stalling when slowing down
  • Limp Home Mode – limits vehicle to one gear and speed limit in order to get the car to a garage (limp home)
  • Fluid leak/burning smell from transmission area – usually red / brownish color or black if things got real bad

Causes of P0702

Depending on the make, model and year of vehicle the causes will vary. Manufacturers use unique electrical designs and engineering so a DTC can mean different things to different vehicles. These are some of the more common causes associated with P0702 being set.

How to Diagnose the P0702 Code?

To properly diagnose this code you will need a computer/scanner, a volt/ohm/amp meter (multi-meter) and probably a wiring schematic. The vehicle should first be road tested to verify concerns and gather data.

Some aftermarket code readers will only give generic codes and not sub group specific. You may have to take it to a licensed shop that has the proper equipment to read your vehicle’s subsystem codes.

Checking Transmission Trouble Code

First you can try clearing the code. Before you erase it, write down all present codes, snapshot any data is about to be cleared and any info from the first road test. If the codes will clear and not return during final road test, the code may have been set by an anomaly or glitch such as a sticky solenoid, valve or erratic sensor reading. Studying freeze frame data might provide insight to the conditions that set the code.

If the codes immediately return or come back consistently on road tests you will have to thoroughly inspect the affected circuit related to the DTC’s. This may require access to internal parts of the transmission as some solenoids and connectors will only be accessible with the transmission oil pan removed.

Common Mistakes When Diagnosing P0702

Under Diagnose

Don’t clear the code and assume because it doesn’t come right back that the vehicle is fixed. A small problem may become a big one.

Over Diagnose

Not getting all codes and data that set the P0702 code and recommending extensive repairs when a wire repair or sensor replacement would have fixed it.

What Repairs Will Fix the P0702 Code?

Codes Related to P0702

Links To Diagnostic Codes

Trouble CodeDescription
P0218Transmission Over Temperature Condition
P0700Transmission Control System (MIL Request)
P0701Transmission Control System Range/Performance
P0702Transmission Control System Electrical
P0703Torque Converter/Brake Switch B Circuit
P0704Clutch Switch In put Circuit Malfunction
P0705Transmission Range Sensor Circuit Malfunction (PRNDL Input)
P0706Transmission Range Sensor Circuit Range/Performance
P0707Transmission Range Sensor Circuit Low Input
P0708Transmission Range Sensor Circuit High Input
P0709Transmission Range Sensor Circuit intermittent
P0710Transmission Fluid Temperature Sensor Circuit
P0711Transmission Fluid Temperature Sensor Circuit Range/Performance
P0712Transmission Fluid Temperature Sensor Circuit Low Input
P0713Transmission Fluid Temperature Sensor Circuit High Input
P0714Transmission Fluid Temperature Sensor Circuit Intermittent P0715
P0715Input/Turbine Speed Sensor Circuit
P0716Input/Turbine Speed Sensor Circuit Range/Performance 
P0717Input/Turbine Speed Sensor Circuit No Signal
P0718Input/Turbine Speed Sensor Circuit Intermittent
P0719Torque Converter/Brake Switch B Circuit Low
P0720Output Speed Sensor Circuit
P0721Output Speed Sensor Circuit Range/Performance
P0722Output Speed Sensor Circuit No Signal
P0723Output Speed Sensor Circuit Intermittent
P0724 Torque Converter/Brake Switch B Circuit High
P0725Engine Speed Input Circuit
P0726Engine Speed Input Circuit Range/Performance
P0727Engine Speed Input Circuit No Signal
P0728Engine Speed Input Circuit Intermittent
P0729Gear 6 Incorrect Ratio
P0730Incorrect Gear Ratio
P0731Gear 1 Incorrect Ratio
P0732Gear 2 Incorrect Ratio
P0733Gear 3 Incorrect Ratio
P0734Gear 4 Incorrect Ratio
P0735Gear 5 Incorrect Ratio
P0736Reverse Incorrect Ratio
P0738TCM Engine Speed Output Circuit
P0739TCM Engine Speed Output Circuit Low
P0740Torque Converter Clutch Circuit Malfunction
P0741Torque Converter Clutch Circuit
P0742Torque Converter Clutch Circuit Stuck On
P0743Torque Converter Clutch Circuit Electrical
P0744Torque Converter Clutch Circuit Intermittent
P0745Pressure Control Solenoid 'A'
P0746Pressure Control Solenoid 'A' Performance or Stuck Off
P0747Pressure Control Solenoid 'A' Stuck On
P0748Pressure Control Solenoid 'A' Electrical
P0749Pressure Control Solenoid 'A' Intermittent
P0750Shift Solenoid 'A'
P0751Shift Solenoid 'A' Performance or Stuck Off
P0752Shift Solenoid 'A' Stuck On
P0753Shift Solenoid 'A' Electrical
P0754Shift Solenoid 'A' Intermittent
P0755Shift Solenoid 'B'
P0756Shift Solenoid 'B' Performance or Stuck Off
P0757Shift Solenoid 'B' Stuck On
P0758Shift Solenoid 'B' Electrical
P0759Shift Solenoid 'B' Intermittent
P0760Shift Solenoid 'C'
P0761Shift Solenoid 'C' Performance or Stuck Off
P0762Shift Solenoid 'C' Stuck On
P0763Shift Solenoid 'C' Electrical
P0764Shift Solenoid 'C' Intermittent
P0765Shift Solenoid 'D'
P0766Shift Solenoid 'D' Performance or Stuck Off
P0767Shift Solenoid 'D' Stuck On
P0768Shift Solenoid 'D' Electrical
P0769Shift Solenoid 'D' Intermittent
P0770Shift Solenoid 'E'
P0771Shift Solenoid 'E' Performance or Stuck Off
P0772Shift Solenoid 'E' Stuck On
P0773Shift Solenoid 'E' Electrical
P0774Shift Solenoid 'E' Intermittent
P0775Pressure Control Solenoid 'B'
P0776Pressure Control Solenoid 'B' Performance or Stuck Off
P0777Pressure Control Solenoid 'B' Stuck On
P0778Pressure Control Solenoid 'B' Electrical
P0779Pressure Control Solenoid 'B' Intermittent
P0780Shift Malfunction
P07811-2 Shift
P07822-3 Shift
P07833-4 Shift
P07844-5 Shift
P0785Shift/Timing Solenoid
P0786Shift/Timing Solenoid Range/Performance
P0787Shift/Timing Solenoid Low
P0788Shift/Timing Solenoid High
P0789Shift/Timing Solenoid Intermittent
P0790Normal/Performance Switch Circuit
P0791Intermediate Shaft Speed Sensor Circuit
P0792Intermediate Shaft Speed Sensor Circuit Range/Performance
P0793Intermediate Shaft Speed Sensor Circuit No Signal
P0794Intermediate Shaft Speed Sensor Circuit Intermittent
P0795Pressure Control Solenoid 'C'
P0796Pressure Control Solenoid 'C' Performance or Stuck off
P0797Pressure Control Solenoid 'C' Stuck On
P0798Pressure Control Solenoid 'C' Electrical
P0799Pressure Control Solenoid 'C' Intermittent

Links To Symptoms

Symptoms
Low Transmission Fluid
Transmission Slipping
Limp Mode
Burnt Transmission Fluid
DTC / Check Engine Codes
Lack of Responses
Torque Converter Problems
Whining, Clunking or Humming
Transmission Fluid Leak
Solenoid Problems

Comments

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