AutoCodes – Generic – P1C99

P1C99 Code - Gear Shift Position Sensor 1 Circuit

Quick Answer

This diagnostic compares the output signal of the sensor to threshold values of normal operations. Common causes include Faulty Gear Shift Position Sensor 1, Gear Shift Position Sensor 1 harness is open or shorted, Gear Shift Position Sensor 1 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: P1C99 indicates Gear Shift Position Sensor 1 Circuit.
Common causes: Common causes include Faulty Gear Shift Position Sensor 1, Gear Shift Position Sensor 1 harness is open or shorted, Gear Shift Position Sensor 1 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 3,395

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 Apr 12, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1C99 Description

This diagnostic compares the output signal of the sensor to threshold values of normal operations. When the signal is out of range the diagnostic will be considered failing. The sensor is mounted next to the 1st - 3rd gear engagement actuator to detect a linear movement of the piston. For this purpose, a permanent magnet is mounted on the piston which is moved over a complete travel stroke. The magnet position generates a saturation area in the internal ferromagnetic core of the sensor which is transformed to an output position signal. The sensor provides an output signal with Pulse Width Modulation (PWM) at a fixed frequency and duty cycle proportional to the piston position of the actuator.

OBDII Code P1C99 - Gear Shift Position Sensor 1 Circuit - AutoCodes.com — P1C99 Code - Gear Shift Position Sensor 1 Circuit

What does this mean?

What are the Possible Causes of the DTC P1C99?

Faulty Gear Shift Position Sensor 1
Gear Shift Position Sensor 1 harness is open or shorted
Gear Shift Position Sensor 1 circuit poor electrical connection
Faulty Transmission Control Module (TCM)

How to Fix the DTC P1C99?

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 P1C99 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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Information for Specific Makes

P1C99 Chrysler — Gear Shift Position Sensor 1 Circuit
P1C99 Dodge — Gear Shift Position Sensor 1 Circuit
P1C99 Fiat — Gear Shift Position Sensor 1 Circuit
P1C99 Jeep — Gear Shift Position Sensor 1 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.

Frequently Asked Questions about P1C99 Code

What does OBDII code P1C99 mean?

OBDII code P1C99 indicates a problem with the Gear Shift Position Sensor 1 Circuit, which monitors the position of the gear shift in automatic transmission vehicles.

What are the common symptoms of P1C99?

Common symptoms include the transmission not shifting properly, the vehicle being stuck in one gear, or the check engine light being illuminated.

What could cause the P1C99 code to trigger?

Causes may include a faulty gear shift position sensor, damaged wiring or connectors, or issues with the transmission control module.

How can I diagnose the issue related to P1C99?

To diagnose, start with a visual inspection of the wiring and connectors, check for any other related trouble codes, and test the gear shift position sensor for proper operation.

Is it safe to drive with the P1C99 code?

Driving with the P1C99 code is not recommended as it may result in erratic shifting or transmission damage, which can lead to safety concerns.

What are some common repairs for code P1C99?

Common repairs include replacing the gear shift position sensor, repairing or replacing damaged wiring, or reprogramming the transmission control module.

How can I prevent the P1C99 code from returning?

To prevent recurrence, ensure regular maintenance of the transmission system, check wiring for wear, and promptly address any shifting issues.

Can I clear the P1C99 code without fixing the issue?

Yes, you can clear the code using an OBDII scanner, but if the underlying problem is not resolved, the code will likely return.

What is the average cost to repair P1C99?

The cost to repair P1C99 can vary widely, but it typically ranges from $100 to $500 depending on whether you need to replace the sensor or repair wiring.