AutoCodes – Chevrolet – P18C2 2015 Chevrolet Silverado

P18C2 2015 Chevrolet Silverado Code - Internal Mode Switch 'P' Circuit Stuck On Invalid Voltage Range

Quick Answer

The internal mode switch indicates the Transmission Control Module (TCM) which gear position the vehicle operator has selected. Common causes include Faulty Transmission Internal Mode Switch, Transmission Internal Mode Switch harness is open or shorted, Transmission Internal Mode Switch 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: P18C2 2015 Chevrolet Silverado indicates Internal Mode Switch 'P' Circuit Stuck On Invalid Voltage Range.
Common causes: Common causes include Faulty Transmission Internal Mode Switch, Transmission Internal Mode Switch harness is open or shorted, Transmission Internal Mode Switch 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 277

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 Mar 23, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P18C2 2015 Chevrolet Silverado Description

The internal mode switch indicates the Transmission Control Module (TCM) which gear position the vehicle operator has selected. The internal mode switch consists of 5 separate hall effect switches. Each hall effect switch is supplied with a 9 V reference circuit and a signal circuit from the TCM. Each signal circuit for each gear selector position will have either a voltage reading of 0.70-0.96 V indicating On or 1.68-2.38 V indicating Off. The voltage values on each internal mode switch circuit will change and are dependent on the position of the gear selector. The state of each internal mode switch A/B/C/P/S signal circuit is displayed on the scan tool. The Diagnostic Trouble Code (DTC) will be set when the TCM has detected the internal mode switch P signal circuit has an invalid voltage range of 0.70 – 0.96 V for 2.7 s.

OBDII Code P18C2 2015 Chevrolet Silverado - Internal Mode Switch 'P' Circuit Stuck On Invalid Voltage Range - AutoCodes.com — P18C2 2015 Chevrolet Silverado Code - Internal Mode Switch 'P' Circuit Stuck On Invalid Voltage Range

What does this mean?

What are the Possible Causes of the DTC P18C2 2015 Chevrolet Silverado?

Faulty Transmission Internal Mode Switch
Transmission Internal Mode Switch harness is open or shorted
Transmission Internal Mode Switch circuit poor electrical connection
Faulty Transmission Control Module (TCM)

How to Fix the DTC P18C2 2015 Chevrolet Silverado?

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 P18C2 2015 Chevrolet Silverado 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 P18C2 2015 Chevrolet Silverado code?

Need more information on how to fix the P18C2 2015 Chevrolet Silverado code? Get Access to Factory Service Manuals

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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 P18C2 2015 Chevrolet Silverado Code

1. What are common symptoms of OBDII code P18C2 in a 2015 Chevrolet Silverado?

- Common symptoms include issues with shifting gears, hesitation or jerking during acceleration, and the inability to start the vehicle.

2. What does the OBDII code P18C2 'Internal Mode Switch 'P' Circuit Stuck On Invalid Voltage Range' mean for a 2015 Chevrolet Silverado?

- This code indicates a problem with the internal mode switch circuit in the transmission control module, specifically related to an invalid voltage range.

3. What are possible causes of OBDII code P18C2 in a 2015 Chevrolet Silverado?

- Possible causes include a faulty internal mode switch, damaged wiring or connectors in the circuit, or issues with the transmission control module itself.

4. How can I diagnose the OBDII code P18C2 in my 2015 Chevrolet Silverado?

- Diagnosing this code typically involves using a scan tool to retrieve the code, checking the internal mode switch for proper operation, and inspecting the wiring and connectors for any damage.

5. Can I drive my 2015 Chevrolet Silverado with OBDII code P18C2?

- It is not recommended to drive the vehicle with this code present, as it can lead to transmission issues and potential safety concerns. It's best to address the problem promptly.

6. How can I repair OBDII code P18C2 in my 2015 Chevrolet Silverado?

- Repair options may include replacing the internal mode switch, repairing any damaged wiring or connectors, or reprogramming the transmission control module to resolve the voltage range issue.

7. Is it possible to reset OBDII code P18C2 in a 2015 Chevrolet Silverado without fixing the underlying issue?

- While you can clear the code with a scan tool, it is important to address the root cause of the problem to prevent it from recurring and potentially causing more significant issues.

8. Are there any DIY tips for fixing OBDII code P18C2 in a 2015 Chevrolet Silverado?

- DIY tips may include checking and cleaning the internal mode switch connections, inspecting the wiring harness for damage, and ensuring all components are securely connected.

9. How much does it typically cost to repair OBDII code P18C2 in a 2015 Chevrolet Silverado?

- The cost of repairs can vary depending on the specific issue causing the code, but it may range from a few hundred to over a thousand dollars, including parts and labor.

10. Can a mechanic help me with diagnosing and fixing OBDII code P18C2 in my 2015 Chevrolet Silverado?

- Yes, a qualified mechanic with experience in diagnosing and repairing transmission-related issues can help identify the cause of the code and perform the necessary repairs to resolve it.