AutoCodes – Chevrolet – P18BC 2017 Chevrolet Silverado

P18BC 2017 Chevrolet Silverado Code - Internal Mode Switch 'C' Circuit Stuck Off 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: P18BC 2017 Chevrolet Silverado indicates Internal Mode Switch 'C' Circuit Stuck Off 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 309

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 P18BC 2017 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 C signal circuit has an invalid voltage range of 1.68 – 2.38 V, for 2.7 s.

OBDII Code P18BC 2017 Chevrolet Silverado - Internal Mode Switch 'C' Circuit Stuck Off Invalid Voltage Range - AutoCodes.com — P18BC 2017 Chevrolet Silverado Code - Internal Mode Switch 'C' Circuit Stuck Off Invalid Voltage Range

What does this mean?

What are the Possible Causes of the DTC P18BC 2017 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 P18BC 2017 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 P18BC 2017 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 P18BC 2017 Chevrolet Silverado code?

Need more information on how to fix the P18BC 2017 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 P18BC 2017 Chevrolet Silverado Code

1. What are the common symptoms of OBDII code P18BC on a 2017 Chevrolet Silverado?

The common symptoms of OBDII code P18BC include issues with shifting gears, hesitation or jerking during acceleration, and the Check Engine light illuminated on the dashboard.

2. What does the Internal Mode Switch 'C' Circuit Stuck Off Invalid Voltage Range mean in relation to code P18BC?

The code P18BC on a 2017 Chevrolet Silverado indicates a problem with the Internal Mode Switch 'C' circuit, specifically that it is stuck off and experiencing an invalid voltage range.

3. What are the possible causes of OBDII code P18BC on a 2017 Chevrolet Silverado?

Possible causes of code P18BC include a faulty internal mode switch, damaged wiring or connectors in the circuit, low transmission fluid level, or issues with the transmission control module.

4. How can I diagnose the Internal Mode Switch 'C' Circuit issue causing code P18BC on my 2017 Chevrolet Silverado?

Diagnosing the Internal Mode Switch 'C' Circuit issue typically involves checking the internal mode switch for proper operation, inspecting wiring and connectors for damage, and testing the circuit for voltage irregularities.

5. Can I continue driving my 2017 Chevrolet Silverado with OBDII code P18BC present?

It is not recommended to drive your vehicle with OBDII code P18BC present, as it can lead to transmission issues and potential safety hazards. It is best to have the problem diagnosed and repaired as soon as possible.

6. Is it possible to reset the OBDII code P18BC on a 2017 Chevrolet Silverado without fixing the underlying issue?

While you can clear the code temporarily by using an OBDII scanner, it will likely reappear if the underlying issue causing code P18BC is not addressed. It is important to diagnose and repair the problem to prevent further issues.

7. How can I repair the Internal Mode Switch 'C' Circuit Stuck Off issue causing OBDII code P18BC on my 2017 Chevrolet Silverado?

Repairing the Internal Mode Switch 'C' Circuit issue may involve replacing the internal mode switch, repairing damaged wiring or connectors, ensuring proper transmission fluid levels, or addressing any issues with the transmission control module.

8. Will fixing the Internal Mode Switch 'C' Circuit issue causing OBDII code P18BC on my 2017 Chevrolet Silverado be costly?

The cost of repairing the Internal Mode Switch 'C' Circuit issue can vary depending on the exact cause of the problem and whether you choose to do the repairs yourself or take your vehicle to a mechanic. It is recommended to get a diagnosis and estimate from a professional.

9. How long does it typically take to repair the Internal Mode Switch 'C' Circuit issue causing OBDII code P18BC on a 2017 Chevrolet Silverado?

The repair time for the Internal Mode Switch 'C' Circuit issue can vary depending on the complexity of the problem and the availability of parts. It may take a few hours to a full day to complete the repair.

10. Can a DIY enthusiast with basic automotive knowledge fix the Internal Mode Switch 'C' Circuit issue causing OBDII code P18BC on a 2017 Chevrolet Silverado?

While some DIY enthusiasts may be able to address simpler issues related to the Internal Mode Switch 'C' Circuit, it is recommended to have a professional diagnosis and repair more complex transmission-related problems to ensure proper resolution and safety.