AutoCodes – Chevrolet – P18B8 2016 Chevrolet Silverado

P18B8 2016 Chevrolet Silverado Code - Internal Mode Switch 'P' Circuit Shorted

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: P18B8 2016 Chevrolet Silverado indicates Internal Mode Switch 'P' Circuit Shorted.
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 276

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 P18B8 2016 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 voltage is between 0.966–1.68 V, for 1.75 s.

OBDII Code P18B8 2016 Chevrolet Silverado - Internal Mode Switch 'P' Circuit Shorted - AutoCodes.com — P18B8 2016 Chevrolet Silverado Code - Internal Mode Switch 'P' Circuit Shorted

What does this mean?

What are the Possible Causes of the DTC P18B8 2016 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 P18B8 2016 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 P18B8 2016 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 P18B8 2016 Chevrolet Silverado code?

Need more information on how to fix the P18B8 2016 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 P18B8 2016 Chevrolet Silverado Code

1. What are the common symptoms of OBDII code P18B8 in a 2016 Chevrolet Silverado?

The common symptoms include issues with shifting gears, hesitation or jerking during acceleration, and the transmission not engaging properly.

2. What does the OBDII code P18B8 'Internal Mode Switch 'P' Circuit Shorted' mean for a 2016 Chevrolet Silverado?

This code indicates a problem with the internal mode switch circuit, specifically related to the 'P' gear position.

3. What are the possible causes of OBDII code P18B8 in a 2016 Chevrolet Silverado?

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

4. How can I diagnose the OBDII code P18B8 in my 2016 Chevrolet Silverado?

Diagnosis typically involves checking the internal mode switch for proper operation, inspecting the wiring and connectors for damage, and using a scan tool to analyze the transmission control module data.

5. What are the repair options for OBDII code P18B8 in a 2016 Chevrolet Silverado?

Repair options may include replacing the internal mode switch, repairing damaged wiring or connectors, or reprogramming the transmission control module.

6. Can I still drive my 2016 Chevrolet Silverado with OBDII code P18B8 present?

It is not recommended to continue driving the vehicle with this code as it can lead to further transmission issues and potential safety risks.

7. How urgent is it to address OBDII code P18B8 in a 2016 Chevrolet Silverado?

It is important to address this code promptly to prevent further damage to the transmission system and ensure the vehicle operates safely and efficiently.

8. Will resetting the OBDII code P18B8 in my 2016 Chevrolet Silverado make it go away permanently?

Simply resetting the code without addressing the underlying issue will not make it go away permanently. The root cause of the problem needs to be diagnosed and repaired.

9. Can a DIY enthusiast fix OBDII code P18B8 in a 2016 Chevrolet Silverado?

Depending on the individual's skill level and access to tools, some DIY enthusiasts may be able to diagnose and repair this code. However, complex transmission issues are best handled by experienced professionals.

10. How much can I expect to pay to repair OBDII code P18B8 in a 2016 Chevrolet Silverado?

The cost of repairing this code can vary depending on the root cause of the issue, the required parts, and labor costs. It is advisable to obtain quotes from reputable mechanics or dealerships for an accurate estimate.