AutoCodes – Generic – P18C6

P18C6 Code - Gear Position Sensor Circuit 2 Low 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: P18C6 indicates Gear Position Sensor Circuit 2 Low 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 1,803

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
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P18C6 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 P18C6 - Gear Position Sensor Circuit 2 Low Voltage - AutoCodes.com — P18C6 Code - Gear Position Sensor Circuit 2 Low Voltage

What does this mean?

What are the Possible Causes of the DTC P18C6?

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

How to Fix the DTC P18C6?

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 P18C6 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 P18C6 code?

Need more information on how to fix the P18C6 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P18C6 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P18C6 Buick — Gear Position Sensor Circuit 2 Low Voltage
P18C6 Cadillac — Gear Position Sensor Circuit 2 Low Voltage
P18C6 Chevrolet — Gear Position Sensor Circuit 2 Low Voltage
P18C6 GMC — Gear Position Sensor Circuit 2 Low 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 P18C6 Code

1. What are common symptoms of OBDII code P18C6 (Gear Position Sensor Circuit 2 Low Voltage)?

- Common symptoms include difficulty shifting gears, incorrect gear display on the dashboard, and potential loss of engine power.

2. What can cause the OBDII code P18C6 to trigger?

- The code P18C6 can be triggered by issues such as a faulty gear position sensor, damaged wiring or connectors in the sensor circuit, or low voltage in the sensor system.

3. How can I diagnose the OBDII code P18C6 related to the Gear Position Sensor Circuit 2 Low Voltage?

- To diagnose the code, you can use a diagnostic scanner to read the error code, inspect the gear position sensor and its wiring for damage, and perform voltage tests on the sensor circuit.

4. Can a faulty battery or alternator cause the OBDII code P18C6 to appear?

- Yes, a weak battery or alternator can lead to low voltage in the gear position sensor circuit, triggering the code P18C6.

5. What are the potential dangers of ignoring the OBDII code P18C6 related to the Gear Position Sensor Circuit 2 Low Voltage?

- Ignoring the code can lead to incorrect gear selection, transmission issues, and possible safety hazards while driving.

6. Is it safe to continue driving with the OBDII code P18C6 active?

- It is not recommended to drive with the code active, as it can cause transmission problems and potentially compromise your safety on the road.

7. How can I repair the OBDII code P18C6 myself?

- DIY repair options include checking and repairing damaged wiring, replacing the gear position sensor if needed, and ensuring proper voltage supply to the sensor circuit.

8. Can a professional mechanic help me fix the OBDII code P18C6?

- Yes, a qualified mechanic can diagnose the issue accurately, perform necessary repairs or replacements, and reset the error code using specialized equipment.

9. Are there any preventive measures to avoid the OBDII code P18C6 in the future?

- Regularly inspecting and maintaining the gear position sensor, checking the wiring for damage, and ensuring the electrical system is in good condition can help prevent the recurrence of the P18C6 code.

10. How much does it typically cost to repair the OBDII code P18C6 related to the Gear Position Sensor Circuit 2 Low Voltage?

- The repair cost can vary depending on the extent of the issue, but it may involve expenses for parts replacement, labor charges, and diagnostic fees, with an estimated range of $100 to $500 or more.

1. What are the common symptoms of OBDII code P18C6 (Gear Position Sensor Circuit 2 Low Voltage)?

- Common symptoms include erratic shifting behavior, difficulty engaging specific gears, and the transmission staying in one gear.

2. What are the possible causes of OBDII code P18C6?

- Possible causes include a faulty gear position sensor, damaged wiring or connectors in the circuit, low voltage in the sensor circuit, or a malfunctioning transmission control module.

3. How can I diagnose the Gear Position Sensor Circuit 2 Low Voltage issue?

- You can diagnose the issue by performing a visual inspection of the wiring and connectors, testing the gear position sensor for proper voltage output, and checking for any stored trouble codes in the transmission control module.

4. Can I drive my vehicle with OBDII code P18C6 present?

- It is not recommended to drive the vehicle with this code present, as it can lead to further transmission issues and potential safety hazards.

5. Is it safe to continue driving if the symptoms of OBDII code P18C6 are not severe?

- It is best to address the issue as soon as possible to prevent any further damage to the transmission and ensure the safety and reliability of your vehicle.

6. How much does it typically cost to repair OBDII code P18C6?

- The cost of repair can vary depending on the underlying cause of the issue, but it may involve replacing the gear position sensor, repairing damaged wiring or connectors, or reprogramming the transmission control module.

7. Can I reset the OBDII code P18C6 by disconnecting the battery?

- While disconnecting the battery may clear the code temporarily, it is not a permanent solution and will not address the root cause of the issue. It is recommended to diagnose and repair the problem to prevent the code from reoccurring.

8. Will OBDII code P18C6 cause my vehicle to go into limp mode?

- In some cases, this code can trigger the transmission to go into limp mode as a safety measure to prevent further damage. If your vehicle is in limp mode, it is best to address the issue promptly.

9. Can a DIY enthusiast repair OBDII code P18C6 at home?

- Depending on the cause of the issue, some DIY enthusiasts with knowledge of automotive repair may be able to address this code at home. However, complex transmission repairs are best left to professionals.

10. How often does OBDII code P18C6 occur in vehicles?

- OBDII code P18C6 related to the Gear Position Sensor Circuit 2 Low Voltage is not as common as some other transmission-related codes, but it can still occur in vehicles with electronic transmission control systems.