AutoCodes – Pontiac – P0850 Pontiac

P0850 Pontiac 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 Pontiac 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 1,974

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
FAQs
Comments
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Code P0850 Pontiac 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 Pontiac - Park/Neutral Position Switch Circuit - AutoCodes.com — P0850 Pontiac Code - Park/Neutral Position Switch Circuit

What does this mean?

What are the Possible Causes of the DTC P0850 Pontiac?

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 Pontiac?

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 Pontiac 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 P0850 Pontiac Code

1. What does the P0850 code mean on a Pontiac?

The P0850 code indicates a problem with the Park/Neutral Position Switch Circuit, which helps the transmission and engine control modules determine if the vehicle is in park or neutral.

2. What are the common symptoms of the P0850 code on a Pontiac?

Symptoms may include difficulty starting the engine, the Check Engine Light illuminating, or improper gear engagement.

3. What causes the P0850 code on a Pontiac?

Common causes include a faulty park/neutral position switch, damaged wiring or connectors, or issues with the transmission control module.

4. Can a P0850 code affect drivability?

Yes, it can cause starting issues and potentially affect the transmission's ability to shift properly.

5. How do you diagnose the P0850 code on a Pontiac?

Diagnosis typically involves checking the park/neutral position switch, inspecting wiring and connectors, and using an OBDII scanner to confirm the code and monitor live data.

6. How do you fix the P0850 code on a Pontiac?

Repairs may include replacing the park/neutral position switch, repairing or replacing damaged wiring, or addressing issues with the transmission control module.

7. Is it safe to drive with the P0850 code on a Pontiac?

Driving with this code is not recommended, as it may cause starting or transmission issues that could lead to unsafe driving conditions.

8. How much does it cost to repair a P0850 code on a Pontiac?

Repair costs vary but typically range from $100 to $300, depending on whether the park/neutral position switch or wiring needs replacement.

9. Can a P0850 code cause the engine to stall?

While it primarily affects starting and shifting, in rare cases, it may contribute to stalling if the switch fails to properly communicate the gear position.

10. Will clearing the P0850 code solve the problem?

Clearing the code may temporarily remove the Check Engine Light, but the underlying issue needs to be fixed to prevent the code from returning.