AutoCodes – Cadillac – P18C5 Cadillac

P18C5 Cadillac Code - Gear Position Sensor Circuit 1 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: P18C5 Cadillac indicates Gear Position Sensor Circuit 1 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 1,033

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 P18C5 Cadillac 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 radial position signal 1 circuit for low and high voltage conditions.

OBDII Code P18C5 Cadillac - Gear Position Sensor Circuit 1 High Voltage - AutoCodes.com — P18C5 Cadillac Code - Gear Position Sensor Circuit 1 High Voltage

What does this mean?

What are the Possible Causes of the DTC P18C5 Cadillac?

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

How to Fix the DTC P18C5 Cadillac?

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 P18C5 Cadillac 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 P18C5 Cadillac Code

1. What are the common symptoms of OBDII code P18C5 in a Cadillac related to the Gear Position Sensor Circuit 1 High Voltage?

- Common symptoms include issues with shifting gears, incorrect gear display on the dashboard, and possible transmission malfunctions.

2. What are the possible causes of the Gear Position Sensor Circuit 1 High Voltage fault code P18C5 in a Cadillac?

- Causes can include a malfunctioning gear position sensor, damaged wiring or connectors in the sensor circuit, or issues with the transmission control module.

3. How can I diagnose the Gear Position Sensor Circuit 1 High Voltage issue in my Cadillac when OBDII code P18C5 is triggered?

- Diagnosis involves checking the gear position sensor for proper operation, inspecting the wiring and connectors for damage, and testing the transmission control module for faults.

4. Is it safe to continue driving my Cadillac with the P18C5 fault code related to the Gear Position Sensor Circuit 1 High Voltage?

- It is not recommended to drive the vehicle with this fault code as it may lead to transmission problems or incorrect gear engagement, potentially causing unsafe driving conditions.

5. Can I reset the OBDII code P18C5 in my Cadillac related to the Gear Position Sensor Circuit 1 High Voltage without fixing the underlying issue?

- While you can clear the code temporarily, it will likely reappear until the root cause of the problem is addressed. Resetting the code without repair may result in ongoing transmission issues.

6. Are there any DIY repair tips for resolving the Gear Position Sensor Circuit 1 High Voltage fault code P18C5 in a Cadillac?

- DIY repair tips include checking and cleaning the sensor connections, inspecting the wiring for damage, and ensuring all components related to the gear position sensor are functioning correctly.

7. How much does it typically cost to repair the Gear Position Sensor Circuit 1 High Voltage fault code P18C5 in a Cadillac?

- Repair costs can vary depending on the exact cause of the issue, but expect expenses for parts and labor to range from $200 to $500 or more at a dealership or repair shop.

8. Will fixing the Gear Position Sensor Circuit 1 High Voltage fault code P18C5 in my Cadillac improve the overall performance of the vehicle?

- Yes, addressing this fault code should help restore proper transmission function, accurate gear selection, and overall driving performance in your Cadillac.

9. Can extreme weather conditions or driving habits contribute to triggering the P18C5 fault code in a Cadillac's Gear Position Sensor Circuit 1 High Voltage?

- Yes, extreme temperatures, moisture exposure, or aggressive driving can potentially impact the sensor's performance and contribute to triggering the fault code.

10. How long does it typically take to repair the Gear Position Sensor Circuit 1 High Voltage fault code P18C5 in a Cadillac?

- The repair time can vary based on the exact issue, but technicians usually require a few hours to a full day to diagnose, fix, and test the gear position sensor circuit in a Cadillac.