AutoCodes – Chevrolet – P1838 2017 Chevrolet Silverado

P1838 2017 Chevrolet Silverado Code - Internal Mode Switch 'A' Circuit High Voltage

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: P1838 2017 Chevrolet Silverado indicates Internal Mode Switch 'A' Circuit High Voltage.
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 221

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 P1838 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 voltage is greater than 2.38 V, for 1.75 s.

OBDII Code P1838 2017 Chevrolet Silverado - Internal Mode Switch 'A' Circuit High Voltage - AutoCodes.com — P1838 2017 Chevrolet Silverado Code - Internal Mode Switch 'A' Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P1838 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 P1838 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 P1838 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 P1838 2017 Chevrolet Silverado code?

Need more information on how to fix the P1838 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 P1838 2017 Chevrolet Silverado Code

1. What are the common symptoms of OBDII code P1838 on a 2017 Chevrolet Silverado?

The common symptoms of OBDII code P1838 include issues with shifting gears, difficulty starting the vehicle, and the Check Engine Light illuminating on the dashboard.

2. What does the Internal Mode Switch 'A' Circuit High Voltage mean for a 2017 Chevrolet Silverado?

The Internal Mode Switch 'A' Circuit High Voltage (P1838) indicates a potential problem with the internal mode switch, which is responsible for communicating gear position to the vehicle's computer.

3. What are the possible causes of OBDII code P1838 on a 2017 Chevrolet Silverado?

Possible causes of code P1838 include a faulty internal mode switch, damaged wiring or connectors related to the switch, or issues with the transmission control module.

4. How can I diagnose OBDII code P1838 on my 2017 Chevrolet Silverado?

Diagnosing code P1838 usually involves using a scan tool to retrieve the specific fault code, checking the internal mode switch and related wiring for damage, and testing the transmission control module for proper functioning.

5. Can I still drive my 2017 Chevrolet Silverado with OBDII code P1838?

It is not recommended to drive your vehicle with OBDII code P1838 present, as it can lead to transmission-related issues and potentially cause further damage. It's best to address the problem promptly.

6. How can I repair OBDII code P1838 on my 2017 Chevrolet Silverado?

Repairing code P1838 may involve replacing the internal mode switch, repairing or replacing damaged wiring or connectors, and ensuring the transmission control module is functioning correctly.

7. Is it possible to reset OBDII code P1838 on a 2017 Chevrolet Silverado?

While you can clear the fault code using a scan tool, it's important to address the underlying issue causing code P1838 to prevent it from reoccurring.

8. Will OBDII code P1838 on a 2017 Chevrolet Silverado cause any long-term damage if left unrepaired?

Leaving OBDII code P1838 unrepaired can potentially lead to transmission problems and other issues over time. It's best to address the problem promptly to prevent further damage.

9. Are there any preventive measures to avoid OBDII code P1838 on a 2017 Chevrolet Silverado?

Regularly servicing your vehicle, checking for any signs of transmission issues, and addressing any warning lights immediately can help prevent OBDII code P1838 from occurring.

10. How much does it typically cost to repair OBDII code P1838 on a 2017 Chevrolet Silverado?

The cost of repairing OBDII code P1838 can vary depending on the underlying issue, parts needed for replacement, and labor costs. It's recommended to consult a professional mechanic for an accurate estimate.