AutoCodes – Buick – P18C7 Buick

P18C7 Buick Code - Gear Position Sensor Circuit 2 High Voltage

Quick Answer

The gear position sensor is a switching transistor mounted to the top of the transmission extension housing. Common causes include Faulty Gear Position Sensor, Gear Position Sensor harness is open or shorted, Gear Position Sensor 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: P18C7 Buick indicates Gear Position Sensor Circuit 2 High Voltage.
Common causes: Common causes include Faulty Gear Position Sensor, Gear Position Sensor harness is open or shorted, Gear Position Sensor 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 927

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 Feb 05, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P18C7 Buick Description

The gear position sensor is a switching transistor mounted to the top of the transmission extension housing. The four wire sensor interfaces directly with the Engine Control Module (ECM). The ECM supplies 5 V to the gear position sensor on a 5 V reference circuit and also provides a ground path on a low reference circuit. The sensor provides a Pulse Width Modulated (PWM) duty cycle to the ECM on two signal circuits that is proportional to the linear and radial position of the corresponding magnet assembly mounted to the shift shaft. The vehicle uses the gear position sensor information primarily for Active Rev Matching and Active Fuel Management. The ECM monitors the linear position signal 2 circuit for low and high voltage conditions.

OBDII Code P18C7 Buick - Gear Position Sensor Circuit 2 High Voltage - AutoCodes.com — P18C7 Buick Code - Gear Position Sensor Circuit 2 High Voltage

What does this mean?

What are the Possible Causes of the DTC P18C7 Buick?

Faulty Gear Position Sensor
Gear Position Sensor harness is open or shorted
Gear Position Sensor circuit poor electrical connection

How to Fix the DTC P18C7 Buick?

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 P18C7 Buick 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 P18C7 Buick Code

1. What are common symptoms of OBDII code P18C7 in a Buick related to the Gear Position Sensor Circuit 2 High Voltage?

- Common symptoms include rough shifting, erratic transmission behavior, and illuminated warning lights on the dashboard.

2. What are the possible causes of OBDII code P18C7 in a Buick indicating an issue with the Gear Position Sensor Circuit 2 High Voltage?

- Possible causes include a faulty gear position sensor, damaged wiring or connectors, a malfunctioning transmission control module, or internal transmission issues.

3. How can I diagnose the OBDII code P18C7 in my Buick related to the Gear Position Sensor Circuit 2 High Voltage?

- Diagnosis involves using a scan tool to read the trouble code, checking the wiring and connectors for damage, testing the gear position sensor, and inspecting the transmission control module.

4. Is it safe to continue driving my Buick with OBDII code P18C7 pointing to a problem with the Gear Position Sensor Circuit 2 High Voltage?

- It is not recommended to drive the vehicle with this code present, as it can lead to further transmission damage and potentially unsafe driving conditions.

5. How can I repair OBDII code P18C7 in my Buick related to the Gear Position Sensor Circuit 2 High Voltage?

- Repair options include replacing the gear position sensor, repairing or replacing damaged wiring or connectors, resetting the trouble code, and ensuring proper transmission operation.

6. Can a DIY enthusiast fix OBDII code P18C7 indicating an issue with the Gear Position Sensor Circuit 2 High Voltage in a Buick?

- While some basic diagnosis and repairs can be done by a DIY enthusiast, complex transmission issues may require professional expertise to ensure proper troubleshooting and repair.

7. How much does it typically cost to repair OBDII code P18C7 in a Buick associated with the Gear Position Sensor Circuit 2 High Voltage?

- Repair costs can vary depending on the exact cause of the issue, but expenses may include parts like the gear position sensor, labor for diagnosis and repair, and potential transmission module programming.

8. Are there any preventative measures to avoid encountering OBDII code P18C7 in a Buick due to Gear Position Sensor Circuit 2 High Voltage problems?

- Regular maintenance checks, prompt attention to any transmission issues, and avoiding rough driving habits can help prevent the occurrence of this trouble code.

9. Can a faulty battery or alternator cause OBDII code P18C7 to trigger in a Buick related to the Gear Position Sensor Circuit 2 High Voltage?

- While rare, electrical issues like a faulty battery or alternator can sometimes lead to voltage irregularities that affect sensor operation and trigger this particular trouble code.

10. What should I do if OBDII code P18C7 persists in my Buick even after repairs related to the Gear Position Sensor Circuit 2 High Voltage?

- If the code persists after repairs, it is advisable to seek assistance from a qualified mechanic or dealership to conduct further diagnostics and ensure the issue is fully resolved.