Engine-Codes - GMC - P0816 GMC

P0816 GMC Code - Downshift Switch Circuit

- Code Popularity: 212 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents
ChatAC AutoCodes.com AI Chat

What are the Possible Causes of the DTC P0816 GMC?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Transmission Shift Lever
  • Transmission Shift Lever harness is open or shorted
  • Transmission Shift Lever circuit poor electrical connection
  • Faulty Body Control Module (BCM)
⚠ Does your GMC have Safety Recalls? → Check here

How to Fix the DTC P0816 GMC?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Search for P0816 GMC Questions and Answers: Search here →

What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P0816 GMC code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

What Does the P0816 GMC Code Mean?

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.

P0816 GMC Code - Downshift Switch Circuit

Need more Information on the Code?

Need more information on how to fix the P0816 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0816 GMC code diagnosed by a professional: Find a repair shop in your area