AutoCodes – Chevrolet – P18BF 2017 Chevrolet Silverado

P18BF 2017 Chevrolet Silverado Code - Internal Mode Switch 'A' 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: P18BF 2017 Chevrolet Silverado indicates Internal Mode Switch 'A' 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 1,062

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 P18BF 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 A signal circuit has an invalid voltage range of 0.70 – 0.96 V, for 2.7 s.

OBDII Code P18BF 2017 Chevrolet Silverado - Internal Mode Switch 'A' Circuit Stuck On Invalid Voltage Range - AutoCodes.com — P18BF 2017 Chevrolet Silverado Code - Internal Mode Switch 'A' Circuit Stuck On Invalid Voltage Range

What does this mean?

What are the Possible Causes of the DTC P18BF 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 P18BF 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 P18BF 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 P18BF 2017 Chevrolet Silverado code?

Need more information on how to fix the P18BF 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 P18BF 2017 Chevrolet Silverado Code

1. What are common symptoms of the OBDII code P18BF in a 2017 Chevrolet Silverado?

Common symptoms include issues with shifting gears, the vehicle staying in one gear, difficulty starting the vehicle, and the Check Engine Light being illuminated.

2. What does the OBDII code P18BF on a 2017 Chevrolet Silverado indicate?

The code P18BF indicates that the Internal Mode Switch 'A' Circuit is stuck on an invalid voltage range, affecting the transmission's operation.

3. What are possible causes of the Internal Mode Switch 'A' Circuit being stuck on an invalid voltage range in a 2017 Chevrolet Silverado?

Potential causes include a faulty internal mode switch, wiring issues, damaged connectors, or a malfunctioning transmission control module.

4. How can I diagnose the cause of the OBDII code P18BF in my 2017 Chevrolet Silverado?

Diagnosing the issue may involve using a scan tool to retrieve the trouble codes, inspecting the internal mode switch and related wiring, and performing voltage tests to pinpoint the problem.

5. Can I continue driving my 2017 Chevrolet Silverado with the P18BF code present?

It is not recommended to drive the vehicle with the P18BF code active, as it can lead to transmission issues and potentially cause further damage.

6. How can I repair the Internal Mode Switch 'A' Circuit stuck on an invalid voltage range in my 2017 Chevrolet Silverado?

Repair options may include replacing the internal mode switch, repairing or replacing damaged wiring, ensuring proper connections, or recalibrating the transmission control module.

7. Will resetting the OBDII code P18BF on my 2017 Chevrolet Silverado make the issue go away?

Simply resetting the code may temporarily turn off the Check Engine Light, but if the underlying issue causing the code is not fixed, it is likely to reappear.

8. How much does it typically cost to repair the P18BF code in a 2017 Chevrolet Silverado?

The cost of repairs can vary depending on the exact cause of the issue, but it may involve parts and labor expenses ranging from a few hundred to over a thousand dollars.

9. Can I fix the Internal Mode Switch 'A' Circuit problem in my 2017 Chevrolet Silverado myself?

While some DIY enthusiasts may be able to diagnose and repair simpler issues related to the P18BF code, more complex problems may require professional expertise to ensure proper resolution.

10. How can I prevent the OBDII code P18BF from recurring in my 2017 Chevrolet Silverado?

Regular maintenance, including checking the transmission system, inspecting wiring and connectors, and addressing any warning signs promptly, can help prevent the code from reappearing.