AutoCodes – Generic – P18C7

P18C7 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 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 2,077

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

What does this mean?

What are the Possible Causes of the DTC P18C7?

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?

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 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.

Need more information about the P18C7 code?

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Information for Specific Makes

P18C7 Buick — Gear Position Sensor Circuit 2 High Voltage
P18C7 Cadillac — Gear Position Sensor Circuit 2 High Voltage
P18C7 Chevrolet — Gear Position Sensor Circuit 2 High Voltage
P18C7 GMC — Gear Position Sensor Circuit 2 High Voltage

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 Code

1. What are the common symptoms of OBDII code P18C7 (Gear Position Sensor Circuit 2 High Voltage)?

The common symptoms include erratic shifting, transmission slipping, and illumination of the Check Engine Light.

2. What are the possible causes of OBDII code P18C7?

Possible causes of this code include a faulty gear position sensor, damaged wiring or connectors in the sensor circuit, or issues with the transmission control module.

3. How is OBDII code P18C7 diagnosed?

Diagnosis involves using a scan tool to retrieve the code, checking the sensor circuit for any visible damage, and testing the gear position sensor's voltage and resistance levels.

4. Can driving with OBDII code P18C7 cause further damage?

Continuing to drive with this code can potentially lead to further transmission issues and may result in more severe damage over time.

5. How can I repair OBDII code P18C7?

Repair options include replacing the gear position sensor, repairing or replacing damaged wiring or connectors, and clearing the trouble code with a scan tool after the repairs are completed.

6. Is it safe to continue driving my vehicle with OBDII code P18C7 present?

It is not recommended to continue driving with this code, as it can lead to transmission problems and potential safety hazards on the road.

7. Can a DIY enthusiast fix OBDII code P18C7 at home?

Depending on your skill level and access to tools, you may be able to address this issue at home by following repair guides and tutorials. However, professional diagnosis and repair are recommended for complex transmission-related issues.

8. How much does it typically cost to repair OBDII code P18C7?

The cost of repairing this code can vary depending on the extent of the damage, the parts needed, and labor costs. It is advisable to consult with a mechanic for an accurate estimate.

9. Are there any preventive measures to avoid OBDII code P18C7 in the future?

Regular maintenance of your vehicle, including checking the transmission system and sensors, can help prevent issues like OBDII code P18C7 from occurring.

10. Can resetting the trouble code clear OBDII code P18C7 permanently?

Resetting the trouble code may temporarily clear the Check Engine Light, but if the underlying issue causing OBDII code P18C7 is not addressed, the code is likely to reappear.