AutoCodes – Generic – P0864

P0864 Code - TCM Communication Circuit Range/Performance

Quick Answer

The Engine Control Module (ECM) monitors the Transmission Control Module (TCM). Common causes include Faulty Transmission Control Module (TCM), Transmission Control Module harness is open or shorted, Transmission Control Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0864 indicates TCM Communication Circuit Range/Performance.
Common causes: Common causes include Faulty Transmission Control Module (TCM), Transmission Control Module harness is open or shorted, Transmission Control Module circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 24,886

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 07, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0864 Description

The Engine Control Module (ECM) monitors the Transmission Control Module (TCM). The Diagnostic Trouble Code (DTC) will be set when the ECM detects a problem communicating with the TCM.

OBDII Code P0864 - TCM Communication Circuit Range/Performance - AutoCodes.com — P0864 Code - TCM Communication Circuit Range/Performance

What does this mean?

What are the Possible Causes of the DTC P0864?

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

How to Fix the DTC P0864?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0864 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0864 code?

Need more information on how to fix the P0864 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0864 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P0864 Audi — TCM Communication Circuit Range/Performance
P0864 Chrysler — TCM Communication Circuit Range/Performance
P0864 Dodge — TCM Communication Circuit Range/Performance
P0864 Jeep — TCM Communication Circuit Range/Performance
P0864 Volkswagen — TCM Communication Circuit Range/Performance

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0864 Code

What does the OBDII code P0864 mean?

The P0864 code indicates a problem with the Transmission Control Module (TCM) communication circuit, specifically involving range or performance issues in the data exchange.

What are the common symptoms of code P0864?

Symptoms may include the check engine light being illuminated, erratic transmission shifting, the vehicle entering limp mode, or poor overall transmission performance.

What causes the P0864 code to appear?

Common causes include a faulty TCM, damaged or corroded wiring and connectors in the communication circuit, or issues with the Powertrain Control Module (PCM).

Can a weak battery or alternator cause code P0864?

Yes, low voltage from a weak battery or failing alternator can disrupt the communication circuit and trigger this code.

How do I diagnose the P0864 code?

Check for other related codes, inspect the TCM wiring and connectors for damage or corrosion, test the battery and alternator for proper voltage, and verify the integrity of the TCM itself.

Is it safe to drive with the P0864 code active?

Driving with this code is not recommended, as it may cause transmission issues such as limp mode or erratic shifting, potentially leading to unsafe driving conditions.

How do I fix the P0864 code?

Repairs may include replacing damaged wiring, cleaning corroded connectors, reprogramming or replacing the TCM, or addressing any underlying power supply issues like a weak battery.

Can a software update fix the P0864 code?

In some cases, a reflash or software update for the TCM or PCM might resolve communication issues, but this depends on the specific vehicle and circumstances.

How much does it cost to repair the P0864 code?

Repair costs can vary widely, ranging from $50 to $150 for minor wiring or connector repairs, to $500 or more for TCM replacement, depending on parts and labor rates.

Will clearing the code fix the issue permanently?

Clearing the code may temporarily turn off the check engine light, but it won’t resolve the underlying problem causing the P0864 code.