Engine-Codes.com
Engine-Codes – Chevrolet – P1840 2015 Chevrolet Silverado

P1840 2015 Chevrolet Silverado Code - Internal Mode Switch 'S' Circuit Low Voltage

Quick Answer

The P1840 diagnostic trouble code (DTC) for a 2015 Chevrolet Silverado indicates an issue with the Internal Mode Switch 'S' Circuit Low Voltage. Common causes include Faulty Internal Mode Switch, Damaged wiring or connectors in the 'S' circuit, Malfunctioning ECM. 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
P1840 2015 Chevrolet Silverado indicates Internal Mode Switch 'S' Circuit Low Voltage.
Common causes
Common causes include Faulty Internal Mode Switch, Damaged wiring or connectors in the 'S' circuit, Malfunctioning ECM.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 17, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P1840 2015 Chevrolet Silverado Description

The P1840 diagnostic trouble code (DTC) for a 2015 Chevrolet Silverado indicates an issue with the Internal Mode Switch 'S' Circuit Low Voltage. The Internal Mode Switch (IMS) is a component of the transmission range sensor that communicates the gear position to the vehicle's engine control module (ECM). The 'S' circuit refers to the signal wire that carries information about the gear selection. When the voltage on this circuit is lower than expected, the ECM detects a fault and triggers the P1840 code.

OBDII Code P1840 2015 Chevrolet Silverado - Internal Mode Switch 'S' Circuit Low Voltage
P1840 2015 Chevrolet Silverado Code - Internal Mode Switch 'S' Circuit Low Voltage

Common Causes of P1840 2015 Chevrolet Silverado

  1. Faulty Internal Mode Switch
  2. Damaged wiring or connectors in the 'S' circuit
  3. Malfunctioning ECM
  4. Issue with the transmission range sensor
  5. Corrosion or moisture in the electrical connections

Symptoms of P1840 2015 Chevrolet Silverado

  1. Erratic shifting behavior
  2. Harsh gear changes
  3. Transmission slipping
  4. Transmission going into limp mode
  5. Check Engine Light illuminated

How to Fix P1840 2015 Chevrolet Silverado

  1. Diagnose the P1840 code using a scan tool to verify the low voltage condition in the 'S' circuit.
  2. Inspect the Internal Mode Switch and wiring for any visible damage or corrosion.
  3. Test the voltage on the 'S' circuit to determine if it falls below the specified range.
  4. Replace the Internal Mode Switch if it is found to be faulty, and repair any damaged wiring or connectors.
  5. Clear the DTC and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P1840 2015 Chevrolet Silverado

The cost of repairing the Internal Mode Switch 'S' Circuit Low Voltage issue on a 2015 Chevrolet Silverado can vary depending on the exact cause of the problem and the labor rates at the repair facility. In general, the cost of replacing the Internal Mode Switch and addressing any wiring issues can range from $200 to $500, including parts and labor. However, it is advisable to check with local auto repair shops for a more accurate estimate based on your specific location and vehicle. Keep in mind that diagnostic time and labor rates can impact the overall cost of the repair.

Need more information about the P1840 2015 Chevrolet Silverado code?

Need more information on how to fix the P1840 2015 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1840 2015 Chevrolet Silverado code diagnosed by a professional: Find a repair shop in your area

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 P1840 2015 Chevrolet Silverado Code

1. What does OBDII code P1840 mean for a 2015 Chevrolet Silverado?

The code P1840 indicates an issue with the Internal Mode Switch 'S' Circuit registering low voltage in a 2015 Chevrolet Silverado.

2. What are the common symptoms of OBDII code P1840 in a 2015 Chevrolet Silverado?

Common symptoms of code P1840 may include issues with shifting gears, erratic transmission behavior, and the check engine light illuminating on the dashboard.

3. What are the possible causes of OBDII code P1840 in a 2015 Chevrolet Silverado?

Potential causes of code P1840 include a faulty internal mode switch, damaged wiring or connectors in the circuit, or a malfunctioning transmission control module.

4. How can I diagnose OBDII code P1840 in my 2015 Chevrolet Silverado?

Diagnosing code P1840 may involve using a diagnostic scanner to retrieve the specific fault codes, inspecting the internal mode switch and related wiring, and testing the transmission control module.

5. Can I continue driving my 2015 Chevrolet Silverado with OBDII code P1840?

It is not recommended to continue driving with code P1840 present, as it can lead to further transmission issues and potential safety hazards. It is advisable to address the problem promptly.

6. How can I repair OBDII code P1840 in my 2015 Chevrolet Silverado?

Repairing code P1840 may involve replacing the internal mode switch, repairing any damaged wiring or connectors, or reprogramming the transmission control module as necessary.

7. Should I reset the fault codes after repairing OBDII code P1840 in my 2015 Chevrolet Silverado?

Once the underlying issue causing code P1840 has been resolved, it is recommended to clear the fault codes using a diagnostic scanner to reset the check engine light and ensure proper functionality.

8. Can a DIY enthusiast fix OBDII code P1840 in a 2015 Chevrolet Silverado?

While some aspects of diagnosing and repairing code P1840 may be within reach of experienced DIY enthusiasts, it is advisable to seek professional assistance, especially for complex transmission-related issues.

9. Is OBDII code P1840 a common problem in 2015 Chevrolet Silverado vehicles?

Code P1840 related to the Internal Mode Switch 'S' Circuit low voltage may occur in 2015 Chevrolet Silverado vehicles, but its frequency can vary depending on factors such as maintenance, driving habits, and vehicle age.

10. What is the typical cost to repair OBDII code P1840 in a 2015 Chevrolet Silverado?

The cost of repairing code P1840 can vary widely based on the specific cause of the issue, parts needed for replacement, labor costs, and whether the repair is done at a dealership or an independent mechanic.

Discuss the causes and fixes for P1840 2015 Chevrolet Silverado OBDII Code

Submit a New Comment

Code P1840 2015 Chevrolet Silverado comments

No comments found for this page.