AutoCodes – Infiniti – P1605 Infiniti

P1605 Infiniti Code - Automatic Transmission Communication

Quick Answer

The malfunction information related to Automatic Transmission is transferred through the line circuit from the Transmission Control Module (TCM) to Engine Control Module (ECM). Common causes include Weak battery, Faulty Transmission Control Module (TCM), Harness is open or shorted between TCM and Engine Control Module (ECM). 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: P1605 Infiniti indicates Automatic Transmission Communication.
Common causes: Common causes include Weak battery, Faulty Transmission Control Module (TCM), Harness is open or shorted between TCM and Engine Control Module (ECM).
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 12,431

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 Sep 30, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P1605 Infiniti Description

The malfunction information related to Automatic Transmission is transferred through the line circuit from the Transmission Control Module (TCM) to Engine Control Module (ECM). The Diagnostic Trouble Code (DTC) will set when an incorrect signal from the Transmission Control Module is sent to Engine Control Module.

OBDII Code P1605 Infiniti - Automatic Transmission Communication - AutoCodes.com — P1605 Infiniti Code - Automatic Transmission Communication

What does this mean?

What are the Possible Causes of the DTC P1605 Infiniti?

Weak battery
Faulty Transmission Control Module (TCM)
Harness is open or shorted between TCM and Engine Control Module (ECM)
Poor circuit electrical connection between TCM and ECM

How to Fix the DTC P1605 Infiniti?

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 does this mean?

Code Tech Notes

There is a Factory Service Bulletin for the 2001 Infiniti I30.
2001 Infiniti I30 Factory Service Bulletin OBDII Code P1605

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1605 Infiniti 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 P1605 Infiniti code?

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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.