AutoCodes – Generic – P0816

P0816 Code - Downshift 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: P0816 indicates Downshift 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 15,010

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
Comments
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Code P0816 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 Down switch for 1 second in Park or Neutral or the BCM detects a stuck On Tap Down switch for 10 minutes in any forward gear.

OBDII Code P0816 - Downshift Switch Circuit - AutoCodes.com — P0816 Code - Downshift Switch Circuit

What does this mean?

What are the Possible Causes of the DTC P0816?

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 P0816?

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 P0816 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.

Need more information about the P0816 code?

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Information for Specific Makes

P0816 Acura — Short In Transmission Gear Selection Switch Upshift/Dowshift Switch Circuit
P0816 Buick — Downshift Switch Circuit
P0816 Cadillac — Downshift Switch Circuit
P0816 Chevrolet — Downshift Switch Circuit
P0816 Chrysler — Downshift Switch Circuit
P0816 Dodge — Downshift Switch Circuit
P0816 GMC — Downshift Switch Circuit
P0816 Honda — Short In Transmission Gear Selection Switch Upshift/Dowshift Switch Circuit
P0816 Jeep — Downshift Switch Circuit
P0816 Mercedes-Benz — Downshift Switch Circuit
P0816 Mitsubishi — Downshift Switch Circuit

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.