Fault code P1700 – a step-by-step guide to diagnosing and fixing it

Error code P1700 is displayed and the check engine light is on - what does this mean?

The DTC P1700 is a manufacturer-specific fault code that mainly occurs in Chrysler, Dodge and Jeep vehicles and indicates a problem in the automatic transmission control module (TCM). The OBD system detects a malfunction in the communication between the transmission control module and other vehicle systems. This code can have different meanings for different manufacturers, but usually refers to transmission or control module problems.

What causes can this error code have?

• Defective transmission control module (TCM)
• Faulty wiring between TCM and other control units
• Corroded or loose plug connections on the transmission control unit
• Faulty fuse in the transmission circuit
• Problems with the power supply to the TCM
• Faulty CAN bus communication
• Damaged ground wire of the transmission control unit
• Software problems in the control module

What symptoms occur in parallel with fault code P1700?

• Shifting problems: The automatic transmission shifts irregularly or not at all
• Emergency running program: The transmission gets stuck in a gear (limp mode)
• Starting problems: The vehicle is difficult or impossible to start
• Loss of power: Reduced engine power and poor acceleration
• Jerking: Unsteady idling or jerking while driving
• Warning lights: Transmission warning light in addition to the engine warning light
• No reverse drive: Reverse gear no longer works

How can the problem with error code P1700 be rectified?

• The repair requires a systematic approach, as several components may be affected.
• Replace the transmission control module: Replace the faulty TCM with a new or reconditioned control unit and have it programmed by a specialist
• Repair wiring: Check and repair all cable connections between the transmission control module and other components, replace damaged cables
• Clean plug connections: Disconnect all connectors on the TCM, clean the contacts with contact spray and restore secure fit
• Check and replace fuses: Check all transmission-related fuses in the engine compartment and interior, replace blown fuses
• Check the power supply: Measure the voltage at the TCM connector and repair any interruptions in the power supply
• Carry out a software update: Have the dealer perform a software update for the transmission control module or reprogram the module