What it means
The transmission control module detects a performance fault in its gear-direction control function.
At a glance
- Usually lights the check-engine light
How it works
The transmission control module manages gear-direction commands for forward and reverse operation and monitors the related transmission response. It also depends on stable power, grounds, wiring, and communication to carry out those commands. This code sets when the module's gear-direction control function does not perform as expected, which may prevent forward or reverse engagement.
Common causes
Most likely first.
- TCM power or ground fault
- TCM internal hardware or software fault
- Related wiring or communication fault
Symptoms
- Transmission warning light
- Failure to engage or select forward or reverse
- Limited shifting or limp mode
How to diagnose it
- Scan the transmission and related modules for codes and freeze-frame data, noting whether forward, reverse, or both directions failed.
- With the vehicle secured and brakes applied, compare the selected direction with transmission range and gear-direction data reported by a capable scan tool.
- Inspect transmission-module power, ground, connectors, and related wiring for loose connections, corrosion, damage, or signs of water intrusion.
- Test module power and ground circuits and relevant communication wiring against the manufacturer's specifications.
- If power, grounds, wiring, and inputs are sound, check for applicable controller software updates and internal module faults using manufacturer diagnostic information.
Common fixes
- Repair loose, corroded, or damaged module power, ground, connector, or communication wiring.
- Correct a range or selector input fault if scan data shows that the requested direction is not reaching the module correctly.
- Reprogram the transmission control module if a manufacturer-approved software update addresses gear-direction control.
- Repair or replace the module only after its circuits, inputs, and software have been checked.
Can I keep driving?
Do not drive if the vehicle cannot reliably engage forward or reverse, or if its selected direction is uncertain. Secure the vehicle and arrange recovery; repeated attempts to engage a direction can worsen transmission damage.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.