AutoCodes – Chevrolet – P18BD 2016 Chevrolet Silverado

P18BD 2016 Chevrolet Silverado Code - Internal Mode Switch 'P' 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: P18BD 2016 Chevrolet Silverado indicates Internal Mode Switch 'P' 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 190

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 P18BD 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 has an invalid voltage range of 1.68 – 2.38 V for 2.7 s.

OBDII Code P18BD 2016 Chevrolet Silverado - Internal Mode Switch 'P' Circuit Stuck Off Invalid Voltage Range - AutoCodes.com — P18BD 2016 Chevrolet Silverado Code - Internal Mode Switch 'P' Circuit Stuck Off Invalid Voltage Range

What does this mean?

What are the Possible Causes of the DTC P18BD 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 P18BD 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 P18BD 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 P18BD 2016 Chevrolet Silverado code?

Need more information on how to fix the P18BD 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 P18BD 2016 Chevrolet Silverado Code

1. What does the OBDII code P18BD mean on a 2016 Chevrolet Silverado?

The code P18BD indicates an issue with the Internal Mode Switch 'P' Circuit, where the voltage range is invalid or the circuit is stuck off.

2. What are the common symptoms of code P18BD in a 2016 Chevy Silverado?

Symptoms may include the inability to shift into or out of park, a non-functioning gear indicator, or the check engine light being illuminated.

3. What causes the P18BD code to appear?

Common causes include a faulty internal mode switch, damaged wiring or connectors, or an issue with the transmission control module (TCM).

4. Can a bad internal mode switch cause the P18BD code?

Yes, a faulty internal mode switch is a primary cause of this code, as it fails to detect the correct "Park" position.

5. How do I diagnose the P18BD code?

Diagnose by inspecting the internal mode switch, checking for damaged or corroded wiring, and verifying the voltage signals using a scan tool.

6. Is it safe to drive with a P18BD code on my Chevrolet Silverado?

Driving may not be safe as the vehicle could have difficulty shifting gears, which might lead to unexpected behavior or safety concerns.

7. How can I fix the P18BD code on a 2016 Chevy Silverado?

Repairs may include replacing the internal mode switch, repairing damaged wiring or connectors, or reprogramming the TCM if necessary.

8. How much does it cost to repair a P18BD code on a 2016 Silverado?

The repair cost can vary, but replacing the internal mode switch typically costs $200-$400, plus diagnostic and labor fees.

9. Can a software update fix the P18BD code?

In some cases, a software update for the TCM may resolve the issue if it is related to programming errors.

10. Do I need a professional mechanic to fix the P18BD code?

While some experienced DIYers may handle basic diagnostics, a professional mechanic with proper tools is recommended for complex repairs like internal mode switch replacement.