AutoCodes – Buick – P0815 Buick

P0815 Buick Code - Upshift Switch Circuit

Quick Answer

The Driver Shift Request (DSR) allows the driver to select the desired range of gears for current driving conditions. Common causes include Faulty Transmission Shift Lever, Transmission Shift Lever harness is open or shorted, Transmission Shift Lever 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: P0815 Buick indicates Upshift Switch Circuit.
Common causes: Common causes include Faulty Transmission Shift Lever, Transmission Shift Lever harness is open or shorted, Transmission Shift Lever 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 412

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 Aug 02, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0815 Buick Description

The Driver Shift Request (DSR) allows the driver to select the desired range of gears for current driving conditions. The DSR shift system is activated when the gear selector is in the manual position. The DSR system is deactivated in all other range positions. Pressing the plus (+) switch once will command the Body Control Module (BCM) to signal the Transmission Control Module (TCM) to upshift to the next high gear. Pressing the minus (−) switch once will command the BCM to signal the TCM to downshift to the next lowest or previous gear. The TCM will not allow a downshift if the transmission is compromised by over-speeding. The automatic transmission manual shift switch is comprised of three different resistor values in series and two switches. The BCM supplies a 12-volt circuit to the automatic transmission manual shift switch. The signal circuit varies the voltage back to the body control module depending on which switch is depressed. The Diagnostic Trouble Code (DTC) will be set when the BCM detects a stuck On Tap Up switch for 1 second in Park or Neutral or the BCM detects a stuck On Tap Up switch for 10 minutes in any forward gear.

OBDII Code P0815 Buick - Upshift Switch Circuit - AutoCodes.com — P0815 Buick Code - Upshift Switch Circuit

What does this mean?

What are the Possible Causes of the DTC P0815 Buick?

Faulty Transmission Shift Lever
Transmission Shift Lever harness is open or shorted
Transmission Shift Lever circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC P0815 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 P0815 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 P0815 Buick Code

1. What does the OBDII code P0815 mean on a Buick?

P0815 indicates an issue with the upshift switch circuit, which is responsible for signaling gear shifts in certain manual or semi-automatic transmissions.

2. What are the common symptoms of the P0815 code in a Buick?

Symptoms may include difficulty shifting gears, the transmission staying in one gear, reduced fuel efficiency, or the check engine light illuminating.

3. What causes the P0815 code to appear in a Buick?

Common causes include a faulty upshift switch, damaged wiring or connectors in the switch circuit, or issues with the transmission control module (TCM).

4. How do I diagnose the P0815 code in my Buick?

Start by scanning for codes using an OBDII scanner, inspect the upshift switch and its circuit for damage or corrosion, and test the switch for proper functionality with a multimeter.

5. Can I drive my Buick with the P0815 code active?

Driving with this code is not recommended as it may lead to poor transmission performance, potential damage, and unsafe driving conditions.

6. How do I fix the P0815 code on a Buick?

Repairs may involve replacing the upshift switch, repairing or replacing damaged wiring, cleaning corroded connectors, or reprogramming the TCM if necessary.

7. How much does it cost to repair the P0815 code in a Buick?

Repair costs vary but typically range from $150 to $450, depending on whether the switch, wiring, or TCM needs repair or replacement.

8. Can a dead battery cause the P0815 code in my Buick?

While a dead battery is not a direct cause, it can lead to voltage issues that may affect the transmission system and potentially trigger this code.

9. How can I prevent the P0815 code from recurring in my Buick?

Regularly inspect and maintain the transmission system, check wiring and connectors for damage, and address any transmission-related issues promptly.

10. Does the P0815 code affect only manual transmission Buicks?

This code is more commonly associated with manual or semi-automatic transmissions but may appear in some automatic transmissions with manual shifting features.