Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the computer in charge of the car's transmission has a memory problem. It's like when your game console can't save your game because the memory is broken.
The Transmission Control Module (TCM) checks its memory for errors. If it finds a problem with the memory's integrity, it triggers this code.
The P1790 code indicates that the TCM has detected an error in its internal memory, specifically related to the checksum or EPROM. This could mean that the data stored in the TCM is corrupted or the memory chip itself is faulty.
• Transmission may not shift properly
• Check Engine Light is on
• Vehicle may go into limp mode
• Faulty Transmission Control Module (TCM)
• Corrupted software in the TCM
• Electrical issues such as poor connections or damaged wiring
TCM: Transmission Control Module, the computer that controls the transmission.
EPROM: Erasable Programmable Read-Only Memory, a type of memory used in computers.
• Scan the vehicle with an OBD-II scanner to confirm the code.
• Inspect the TCM and its wiring for any visible damage.
• Check for any software updates for the TCM.
• Reprogram or update the TCM software.
• Repair or replace damaged wiring or connectors.
• Replace the TCM if it is faulty.
• OBD-II scanner
• Multimeter
• Diagnostic software for TCM
$300 - $1,200
Moderate
• Chrysler 300
• Dodge Ram
• Jeep Grand Cherokee
• Regularly update the vehicle's software.
• Ensure electrical connections are secure.
• Avoid exposing the vehicle to extreme temperatures.
Transmission Control Module Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional.
• Avoid driving the vehicle if it is in limp mode.
Check with your vehicle manufacturer; TCM issues may be covered under powertrain warranty.
This code has been more common in vehicles with aging electronics or those that have not received software updates.
Moderate – It is important to address this issue to prevent further transmission problems.
Driving with a faulty TCM can lead to unsafe driving conditions. Address the issue promptly.
• Vehicle should be at operating temperature.
• Perform tests in a controlled environment to avoid accidents.
The Transmission Control Module is typically located near the transmission or within the engine compartment.
Q: Can I drive with a P1790 code?
A: It's not recommended as it can lead to transmission issues and unsafe driving conditions.
Q: How can I prevent a P1790 code?
A: Regular maintenance and software updates can help prevent this issue.
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