AutoCodes – GMC – P0608 GMC

P0608 GMC Code - Vehicle Speed Output Circuit

Quick Answer

Various components apply a voltage to the Vehicle Speed Output circuit. Common causes include Faulty Vehicle Speed Sensor, Vehicle Speed Sensor harness is open or shorted, Vehicle Speed Sensor circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0608 GMC indicates Vehicle Speed Output Circuit.
Common causes: Common causes include Faulty Vehicle Speed Sensor, Vehicle Speed Sensor harness is open or shorted, Vehicle Speed Sensor circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 3,623

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0608 GMC Description

Various components apply a voltage to the Vehicle Speed Output circuit. The Powertrain Control Module (PCM) creates the Vehicle Speed Output signal by rapidly grounding this circuit via an internal switch called a driver. The driver operates at the same rate as the VSS signal input. The various components recognize the voltage being pulled to ground as an indication of vehicle speed.
The driver supplies the ground for the component being controlled. Each driver has a fault line which the PCM monitors. When the PCM commands a component ON, the voltage of the control circuit should be low (near 0 volts). When the PCM commands the control circuit to a component OFF, the voltage potential of the circuit should be high (near battery voltage).

OBDII Code P0608 GMC - Vehicle Speed Output Circuit - AutoCodes.com — P0608 GMC Code - Vehicle Speed Output Circuit

What does this mean?

What are the Possible Causes of the DTC P0608 GMC?

Faulty Vehicle Speed Sensor
Vehicle Speed Sensor harness is open or shorted
Vehicle Speed Sensor circuit poor electrical connection

How to Fix the DTC P0608 GMC?

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 P0608 GMC 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.

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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.