P0865 Fault Code

TCM Communication Circuit Low

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0865 fault code signifies an issue with the Transmission Control Module (TCM) communication circuit. This code indicates that the TCM is not receiving the necessary voltage or signal, leading to possible transmission malfunctions and poor vehicle performance.

What are the symptoms of the P0865 code?

Symptoms associated with the P0865 code may include:

• Illumination of the check engine light
• Erratic shifting behavior or delayed shifting
• Transmission slipping or failure to engage
• Vehicle entering limp mode, limiting performance to protect the transmission.

What causes the P0865 code?

Common causes of the P0865 code include:

• Damaged wiring or connectors in the TCM circuit
• Faulty TCM
• Low transmission fluid levels
• Poor electrical connections
• Issues with other related sensors that impact the TCM functioning.

How to fix P0865?

To resolve the P0865 code, consider the following steps:

• Inspect the wiring and connectors for any signs of damage or corrosion and repair as necessary.
• Check transmission fluid levels and condition, and top off or replace as needed.
• Test the TCM for faults and replace it if found to be defective.
• Clear the trouble code and test drive the vehicle to ensure the issue is resolved.