AutoCodes – Chevrolet – P1841 2018 Chevrolet Silverado

P1841 2018 Chevrolet Silverado Code - Internal Mode Switch 'S' 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: P1841 2018 Chevrolet Silverado indicates Internal Mode Switch 'S' 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 264

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 P1841 2018 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 S signal circuit voltage is greater than 2.38 V, for 1.75 s.

OBDII Code P1841 2018 Chevrolet Silverado - Internal Mode Switch 'S' Circuit High Voltage - AutoCodes.com — P1841 2018 Chevrolet Silverado Code - Internal Mode Switch 'S' Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P1841 2018 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 P1841 2018 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 P1841 2018 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 P1841 2018 Chevrolet Silverado code?

Need more information on how to fix the P1841 2018 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 P1841 2018 Chevrolet Silverado Code

1. What does the OBDII code P1841 mean on a 2018 Chevrolet Silverado?

P1841 signifies an issue with the Internal Mode Switch (IMS) 'S' Circuit, where the system has detected high voltage in the circuit.

2. What are the common symptoms of a P1841 code in a 2018 Chevrolet Silverado?

Symptoms can include erratic transmission shifting, the transmission staying in one gear, the check engine light illuminating, or reduced vehicle performance.

3. What causes the P1841 code to appear on a Chevrolet Silverado?

Common causes include a faulty internal mode switch, damaged wiring or connectors in the IMS circuit, corrosion at electrical connections, or a malfunctioning transmission control module (TCM).

4. Can I drive my 2018 Chevrolet Silverado with a P1841 code?

Driving with this code is not recommended as it may lead to poor transmission performance, further damage, or unsafe driving conditions.

5. How do I diagnose the P1841 code on my Silverado?

Start by using an OBDII scanner to confirm the code, then inspect the IMS circuit for damaged wiring, loose connections, or corrosion. Test the switch and related components with a multimeter if needed.

6. How do I fix the P1841 code on a 2018 Chevrolet Silverado?

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

7. How much does it cost to repair a P1841 code on a Chevrolet Silverado?

Repair costs can vary widely, ranging from $100 for minor wiring repairs to $800 or more if the internal mode switch or TCM needs replacement and reprogramming.

8. Can a bad battery cause the P1841 code to appear?

While unlikely, a weak or failing battery could indirectly contribute to voltage irregularities in the electrical system. Itâ€™s worth testing the battery and charging system as part of the diagnostic process.

9. Is the P1841 code specific to Chevrolet Silverado trucks?

No, the P1841 code can appear on other vehicles, but the diagnosis and repair process may vary depending on the make and model.

10. Do I need a professional mechanic to fix the P1841 code?

If youâ€™re familiar with automotive electrical systems and have the right tools, you may be able to repair it yourself. However, more complex issues, like TCM programming, often require professional assistance.