AutoCodes – Generic – P0838

P0838 Code - Four Wheel Drive Switch Circuit Low

Quick Answer

The Transmission Control Module (TCM) monitors the Four Wheel Drive Switch Circuit signal. Common causes include Faulty Four Wheel Drive Switch, Four Wheel Drive Switch harness is open or shorted, Four Wheel Drive Switch 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: P0838 indicates Four Wheel Drive Switch Circuit Low.
Common causes: Common causes include Faulty Four Wheel Drive Switch, Four Wheel Drive Switch harness is open or shorted, Four Wheel Drive Switch 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 10,485

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 May 10, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0838 Description

The Transmission Control Module (TCM) monitors the Four Wheel Drive Switch Circuit signal. the TCM sets the OBDII code when the Four Wheel Drive Switch Circuit is not to factory specifications.

OBDII Code P0838 - Four Wheel Drive Switch Circuit Low - AutoCodes.com — P0838 Code - Four Wheel Drive Switch Circuit Low

What does this mean?

What are the Possible Causes of the DTC P0838?

Faulty Four Wheel Drive Switch
Four Wheel Drive Switch harness is open or shorted
Four Wheel Drive Switch circuit poor electrical connection

How to Fix the DTC P0838?

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 P0838 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 P0838 code?

Need more information on how to fix the P0838 code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific Makes

P0838 Chrysler — Four Wheel Drive Switch Circuit Low
P0838 Dodge — Four Wheel Drive Switch Circuit Low
P0838 Jeep — Four Wheel Drive Switch Circuit Low
P0838 Mercedes-Benz — Four Wheel Drive Switch Circuit Low

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.