AutoCodes – Saturn – P0850 Saturn

P0850 Saturn Code - Park/Neutral Position Switch Circuit

Quick Answer

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. Common causes include Faulty Park/Neutral Switch, Park/Neutral Switch harness is open or shorted, Park/Neutral 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: P0850 Saturn indicates Park/Neutral Position Switch Circuit.
Common causes: Common causes include Faulty Park/Neutral Switch, Park/Neutral Switch harness is open or shorted, Park/Neutral 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 1,715

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 10, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0850 Saturn 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 enable, 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 ECM Park/Neutral diagnostic monitors the Park/Neutral Signal circuit to detect Low voltage when the ECM expects to see High voltage and High voltage when the ECM expects to see Low voltage.

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

What does this mean?

What are the Possible Causes of the DTC P0850 Saturn?

Faulty Park/Neutral Switch
Park/Neutral Switch harness is open or shorted
Park/Neutral Switch circuit poor electrical connection

How to Fix the DTC P0850 Saturn?

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 P0850 Saturn 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.