Engine-Codes - Generic - P0866

P0866 Code - TCM Communication Circuit High

- Code Popularity: 8,590 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents

|What are the Possible Causes of the Code P0866?

  • Faulty Transmission Control Module (TCM)
  • Transmission Control Module (TCM) harness is open or shorted
  • Transmission Control Module (TCM) circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

|How to Fix the P0866 Code?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

|What is the Cost to Diagnose the Code P0866?

Labor: 1.0

The cost to diagnose the P0866 code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.

Does your Car have Safety Recalls? → Check here

|What are Code P0866 Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

|What Does the P0866 Code Mean?

The Engine Control Module (ECM) monitors the Transmission Control Module (TCM). The ECM sets the OBDII when there is a problem communicating with the TCM.

P0866 Code - TCM Communication Circuit High

|Need more Information on the P0866 Code?

Need more information on how to fix the P0866 code? Get Access to Factory Service Manuals

|Code P0866 Information for Specific Makes

|Need Help with the P0866 Code?

Get the P0866 code diagnosed by a professional: Find a repair shop in your area