AutoCodes – GMC – P18B5 2014 GMC Sierra

P18B5 2014 GMC Sierra Code - Internal Mode Switch 'A' 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: P18B5 2014 GMC Sierra indicates Internal Mode Switch 'A' 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 162

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 P18B5 2014 GMC Sierra 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 voltage is between 0.966–1.68 V, for 1.75 s.

OBDII Code P18B5 2014 GMC Sierra - Internal Mode Switch 'A' Circuit Shorted - AutoCodes.com — P18B5 2014 GMC Sierra Code - Internal Mode Switch 'A' Circuit Shorted

What does this mean?

What are the Possible Causes of the DTC P18B5 2014 GMC Sierra?

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 P18B5 2014 GMC Sierra?

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 P18B5 2014 GMC Sierra 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 P18B5 2014 GMC Sierra code?

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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 P18B5 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code P18B5 in a 2014 GMC Sierra?

- Common symptoms include issues with shifting gears, hesitation when accelerating, and the transmission not responding correctly to driver inputs.

2. What does the OBDII code P18B5 'Internal Mode Switch 'A' Circuit Shorted' mean for a 2014 GMC Sierra?

- This code indicates a problem with the internal mode switch circuit 'A' in the transmission control module, leading to potential transmission operation issues.

3. What are the possible causes of OBDII code P18B5 in a 2014 GMC Sierra?

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

4. How can I diagnose the Internal Mode Switch 'A' Circuit Shorted issue in my 2014 GMC Sierra?

- Diagnosing the problem involves using a scan tool to retrieve the OBDII code, checking the wiring and connectors for damage, and testing the internal mode switch for proper operation.

5. Can I continue driving my 2014 GMC Sierra with OBDII code P18B5 present?

- It is not recommended to continue driving with this code present, as it can lead to transmission malfunctions and potential safety hazards on the road.

6. How can I repair the Internal Mode Switch 'A' Circuit Shorted issue in my 2014 GMC Sierra?

- Repairing this issue may involve replacing the internal mode switch, repairing damaged wiring or connectors, or reprogramming the transmission control module to resolve the circuit shorted problem.

7. Is it possible to reset the OBDII code P18B5 in a 2014 GMC Sierra without fixing the underlying issue?

- While you can clear the code using a scan tool, it is crucial to address the root cause of the problem to prevent further transmission issues and ensure proper vehicle operation.

8. Will a faulty internal mode switch cause permanent damage to my 2014 GMC Sierra's transmission?

- Continuing to drive with a faulty internal mode switch can potentially cause damage to the transmission if left unresolved, leading to costly repairs in the future.

9. How much does it typically cost to repair the Internal Mode Switch 'A' Circuit Shorted issue in a 2014 GMC Sierra?

- The cost of repair can vary depending on the exact cause of the problem, but it may range from a few hundred to over a thousand dollars, including parts and labor.

10. Can I prevent OBDII code P18B5 from occurring in my 2014 GMC Sierra in the future?

- Regular maintenance, including checking the transmission system for any signs of wear or damage, can help prevent issues like the Internal Mode Switch 'A' Circuit Shorted problem from occurring.