AutoCodes – Buick – P0504 Buick

P0504 Buick Code - TCC Brake Switch/Cruise Control Input Mismatch

Quick Answer

The Engine Control Module (ECM) monitors the stop lamp switch signal circuit and the Torque Converter Clutch (TCC) Brake Switch/Cruise Control release signal circuit every 100 ms. Common causes include Faulty Torque Converter Clutch (TCC)/Cruise Control Release Switch, TCC/Cruise Control Release Switch harness is open or shorted, TCC/Cruise Control Release 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: P0504 Buick indicates TCC Brake Switch/Cruise Control Input Mismatch.
Common causes: Common causes include Faulty Torque Converter Clutch (TCC)/Cruise Control Release Switch, TCC/Cruise Control Release Switch harness is open or shorted, TCC/Cruise Control Release 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 838

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 01, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0504 Buick Description

The Engine Control Module (ECM) monitors the stop lamp switch signal circuit and the Torque Converter Clutch (TCC) Brake Switch/Cruise Control release signal circuit every 100 ms. The ECM monitors the status of the stop lamp switch signal circuit and the TCC Brake Switch/Cruise Control signal circuit to see if they match when the brake pedal is pressed or released. The status of the stop lamp switch input to the ECM and the TCC Brake Switch/Cruise Control input to the ECM does not match for at least 2 seconds continuously, for 10 occurrences. Each time the signals match then do not match a counter increments. When the counter reaches 10 the Diagnostic Trouble Code (DTC) will set.

OBDII Code P0504 Buick - TCC Brake Switch/Cruise Control Input Mismatch - AutoCodes.com — P0504 Buick Code - TCC Brake Switch/Cruise Control Input Mismatch

What does this mean?

What are the Possible Causes of the DTC P0504 Buick?

Faulty Torque Converter Clutch (TCC)/Cruise Control Release Switch
TCC/Cruise Control Release Switch harness is open or shorted
TCC/Cruise Control Release Switch circuit poor electrical connection
Faulty Stop Lamp Switch
Faulty Engine Control Module (ECM)

How to Fix the DTC P0504 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 P0504 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.