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P0850 GMC Code - Park/Neutral Position Switch Circuit

- Code Popularity: 1,825 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 2/3
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What are the Possible Causes of the DTC P0850 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 Internal Mode Switch (IMS)
  • Transmission Internal Mode Switch harness is open or shorted
  • Transmission Internal Mode Switch circuit poor electrical connection
  • Faulty Control Solenoid Valve Assembly
  • Faulty Engine Control Module (ECM)
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How to Fix the DTC P0850 GMC?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0850 GMC code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

What are Code Possible Symptoms?

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

Code P0850 GMC Description

The transmission manual shift shaft switch assembly, also known as the Internal Mode Switch (IMS), is a sliding contact switch attached to the manual shift shaft inside the transmission case. The Park/Neutral Position (PNP) Switch is integrated into the IMS and connects to the Transmission Control Module (TCM) lead frame through a short wire harness. The 5 inputs to the TCM from the transmission manual shift shaft switch assembly indicate the transmission gear selector lever position. This information is used for engine start enabling, engine controls as well as determining the transmission shift patterns.
The state of each input is available for display on the scan tool. The five input parameters represented are Signal A, Signal B, Signal C, Signal P (Parity), and Signal N (Park/Neutral Start Signal). Park/Neutral Signal is sent from the Park/Neutral switch directly to the Engine Control Module (ECM) and is used for engine start enable. The Park/Neutral Signal circuit is not connected to the TCM internally; the circuit uses the TCM as a pass-through connector only. The Diagnostic Trouble Code (DTC) will be set when the ECM detects the Park/Neutral switch signal equals 0 V, Low, when the IMS reports a Drive range.

OBDII Code P0850 GMC - Park/Neutral Position Switch Circuit - AutoCodes.com
P0850 GMC Code - Park/Neutral Position Switch Circuit

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Code P0850 GMC comments

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