Engine-CodesBuick – P0502 Buick

P0502 Buick Code - Vehicle Speed Sensor Circuit Low Input

Quick Answer

The P0502 Buick diagnostic trouble code refers to a Vehicle Speed Sensor Circuit Low Input. Common causes include Faulty Vehicle Speed Sensor, Damaged wiring or connectors in the VSS circuit, Corrosion in the VSS circuit. 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, Damaged wiring or connectors in the VSS circuit, Corrosion in the VSS circuit.
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.
Table of contents Created and updated by William Orellana on Sep 07, 2024
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Code P0502 Buick Description

The P0502 Buick diagnostic trouble code refers to a Vehicle Speed Sensor Circuit Low Input. The Vehicle Speed Sensor (VSS) is a crucial component in a vehicle's system as it provides the Engine Control Module (ECM) with real-time data on the vehicle's speed. The ECM uses this information to calculate various parameters such as fuel injection timing, transmission shifting, and cruise control settings. When the ECM receives a low input signal from the VSS, it triggers the P0502 code, indicating that there is an issue with the VSS circuit.

OBDII Code P0502 Buick - Vehicle Speed Sensor Circuit Low Input
P0502 Buick Code - Vehicle Speed Sensor Circuit Low Input

Common Causes of P0502 Buick

  1. Faulty Vehicle Speed Sensor
  2. Damaged wiring or connectors in the VSS circuit
  3. Corrosion in the VSS circuit
  4. Malfunctioning Engine Control Module (ECM)
  5. Issues with the transmission system

Symptoms of P0502 Buick

  1. Inaccurate speedometer readings
  2. Erratic shifting patterns
  3. Limp mode activation
  4. Engine stalling
  5. Decreased fuel efficiency

How to Fix P0502 Buick

  1. Begin by conducting a visual inspection of the VSS and its wiring to check for any obvious signs of damage or corrosion.
  2. Use a multimeter to test the continuity and resistance of the VSS circuit to determine if there are any electrical issues.
  3. If the VSS circuit checks out, proceed to test the VSS itself using a scan tool to monitor its output signal while the vehicle is in motion.
  4. If the VSS is found to be faulty, replace it with a new one following the manufacturer's guidelines and reset the ECM to clear the trouble code.
  5. After completing the repair, test drive the vehicle to ensure that the issue has been resolved and that the ECM is receiving accurate speed data from the VSS.

Cost to Fix P0502 Buick

The typical repair costs for addressing a P0502 Buick code can range from $150 to $300, including parts and labor. However, it's essential to note that the specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It's advisable to check local rates for a more precise estimate. Labor rates at auto repair shops commonly range between $80 and $150 per hour, with rates potentially higher in metropolitan areas or at dealerships and lower at independent shops.

When is the Code Detected?

If the Powertrain Control Module (PCM) detects a low vehicle speed when there is a high engine speed in a drive gear range, then DTC P0502 sets.

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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

No Frequently Asked Questions about P0502 Buick Code found.

Discuss the causes and fixes for P0502 Buick OBDII Code

  • 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