AutoCodes – Chevrolet – P18C0 Chevrolet

P18C0 Chevrolet Code - Internal Mode Switch 'B' 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: P18C0 Chevrolet indicates Internal Mode Switch 'B' 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.

Save to My Repairs My Repairs

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

Code Popularity 1,744

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
Add Comment

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

Code P18C0 Chevrolet 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 B signal circuit has an invalid voltage range of 0.70 – 0.96 V for 2.7 s.

OBDII Code P18C0 Chevrolet - Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range - AutoCodes.com — P18C0 Chevrolet Code - Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range

What does this mean?

What are the Possible Causes of the DTC P18C0 Chevrolet?

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 P18C0 Chevrolet?

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 P18C0 Chevrolet 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 P18C0 Chevrolet code?

Need more information on how to fix the P18C0 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P18C0 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

P18C0 2014 Chevrolet Silverado — Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range
P18C0 2015 Chevrolet Silverado — Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range
P18C0 2016 Chevrolet Silverado — Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range
P18C0 2017 Chevrolet Silverado — Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range
P18C0 2018 Chevrolet Silverado — Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range

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 P18C0 Chevrolet Code

1. What are common symptoms of OBDII code P18C0 in a Chevrolet related to the Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range?

- Common symptoms include issues with gear shifting, rough shifting, incorrect gear display on the dashboard, and potential stalling of the vehicle.

2. What are the possible causes of OBDII code P18C0 in a Chevrolet indicating the Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range?

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

3. How can I diagnose the OBDII code P18C0 related to the Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range in my Chevrolet?

- Diagnose the code by checking the internal mode switch for proper operation, inspecting the wiring and connectors for any damage, testing the battery voltage, and scanning the transmission control module for related faults.

4. Can I continue driving my Chevrolet with OBDII code P18C0 indicating the Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range?

- It is not recommended to continue driving the vehicle with this code present, as it can lead to potential transmission issues and unsafe driving conditions.

5. How can I repair OBDII code P18C0 related to the Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range in my Chevrolet?

- Repair options may include replacing the internal mode switch, repairing or replacing damaged wiring or connectors, ensuring proper battery voltage, and reprogramming or replacing the transmission control module if necessary.

6. Is it possible to reset OBDII code P18C0 in a Chevrolet without fixing the underlying issue?

- While you can clear the code using an OBDII scanner, it will likely reappear if the root cause of the Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range is not addressed.

7. How much does it typically cost to repair OBDII code P18C0 in a Chevrolet related to the Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range?

- The cost of repair can vary depending on the specific issue, but it may involve parts replacement, wiring repairs, or module reprogramming, potentially ranging from a few hundred to over a thousand dollars.

8. Are there any preventive measures to avoid encountering OBDII code P18C0 in a Chevrolet due to the Internal Mode Switch 'B' Circuit Stuck On Invalid Voltage Range?

- Regular maintenance checks, prompt addressing of any transmission-related issues, and ensuring proper battery health can help prevent the occurrence of this code.