AutoCodes – Buick – P0502 Buick

P0502 Buick Code - Vehicle Speed Sensor Circuit Low Input

Quick Answer

The Vehicle Speed Sensor (VSS) assembly provides vehicle speed information to the Powertrain Control Module (PCM). Common causes include Faulty Vehicle Speed Sensor, Vehicle speed sensor harness or connectors is open or shorted, Vehicle speed sensor 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: P0502 Buick indicates Vehicle Speed Sensor Circuit Low Input .
Common causes: Common causes include Faulty Vehicle Speed Sensor, Vehicle speed sensor harness or connectors is open or shorted, Vehicle speed sensor 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 19,271

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 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 P0502 Buick Description

The Vehicle Speed Sensor (VSS) assembly provides vehicle speed information to the Powertrain Control Module (PCM). The VSS assembly is a Permanent Magnet (PM) generator. The PM generator produces a pulsing AC voltage as rotor teeth on the transmission output shaft pass through the sensor's magnetic field. The AC voltage level and the number of pulses increase as the speed of the vehicle increases. The PCM converts the pulsing voltage to vehicle speed. The PCM uses the vehicle speed signal to determine shift timing and torque converter clutch (TCC) scheduling.

Vehicle Speed Sensor Location Example:

OBDII Code P0502 Buick - Vehicle Speed Sensor Circuit Low Input - AutoCodes.com — P0502 Buick Code - Vehicle Speed Sensor Circuit Low Input

What does this mean?

What are the Possible Causes of the DTC P0502 Buick?

Faulty Vehicle Speed Sensor
Vehicle speed sensor harness or connectors is open or shorted
Vehicle speed sensor circuit poor electrical connection
Faulty Powertrain Control Module (PCM)

How to Fix the DTC P0502 Buick?

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 P0502 Buick 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.

Frequently Asked Questions about P0502 Buick Code

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Mwansa Paul Muyembe
Date: April 26, 2015 at 4:52 pm

hello sir,madam
my mazda familia s wagon 2002 model,chassis #Bj5w-319321 has a PO0733 tranmission gear #3 incorrect ratio and PO745 EPC circuit fault.
please assist

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