AutoCodes – Chevrolet – P1839 2017 Chevrolet Silverado

P1839 2017 Chevrolet Silverado Code - Internal Mode Switch 'C' Circuit Low 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: P1839 2017 Chevrolet Silverado indicates Internal Mode Switch 'C' Circuit Low 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 379

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 P1839 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 C signal circuit voltage is less than 0.7 V, for 1.75 s.

OBDII Code P1839 2017 Chevrolet Silverado - Internal Mode Switch 'C' Circuit Low Voltage - AutoCodes.com — P1839 2017 Chevrolet Silverado Code - Internal Mode Switch 'C' Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P1839 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 P1839 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 P1839 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 P1839 2017 Chevrolet Silverado code?

Need more information on how to fix the P1839 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 P1839 2017 Chevrolet Silverado Code

1. What are the common symptoms of OBDII code P1839 in a 2017 Chevrolet Silverado?

The common symptoms include issues with shifting gears, transmission slipping, and the vehicle may go into limp mode.

2. What can cause the Internal Mode Switch 'C' Circuit Low Voltage code in a 2017 Chevrolet Silverado?

Possible causes include a faulty internal mode switch, damaged wiring or connectors, low voltage in the circuit, or a problem with the transmission control module.

3. How serious is the P1839 code in a 2017 Chevrolet Silverado?

The P1839 code can cause significant transmission issues and potentially lead to further damage if not addressed promptly. It is important to diagnose and repair the issue as soon as possible.

4. Can I continue driving my 2017 Chevrolet Silverado with the Internal Mode Switch 'C' Circuit Low Voltage code?

It is not recommended to continue driving the vehicle with this code present, as it can lead to transmission problems and potentially unsafe driving conditions.

5. How can I diagnose the Internal Mode Switch 'C' Circuit Low Voltage issue in my 2017 Chevrolet Silverado?

Diagnosis typically involves using a scan tool to read the OBDII codes, checking the internal mode switch and related wiring for damage, and testing the voltage in the circuit.

6. Can I repair the P1839 code in my 2017 Chevrolet Silverado myself?

Depending on your level of automotive expertise, you may be able to repair the issue yourself by replacing the internal mode switch, repairing damaged wiring, or addressing any other identified causes. However, professional help is recommended for more complex repairs.

7. Is it expensive to fix the Internal Mode Switch 'C' Circuit Low Voltage code in a 2017 Chevrolet Silverado?

The cost of repairs for this code can vary depending on the root cause of the issue and whether professional help is needed. It's best to get a diagnostic assessment to determine the exact cost.

8. How long does it take to repair the P1839 code in a 2017 Chevrolet Silverado?

The repair time can vary based on the specific cause of the issue and the complexity of the repair. Simple fixes like replacing a sensor may take less time compared to more extensive repairs involving the transmission control module.

9. Will resetting the OBDII code P1839 in my 2017 Chevrolet Silverado make it go away permanently?

Resetting the code may temporarily clear the warning light, but if the underlying issue causing the code is not fixed, it is likely to reappear. It's crucial to address the root cause of the problem for a permanent solution.

10. Can the OBDII code P1839 in a 2017 Chevrolet Silverado affect fuel efficiency?

Yes, if left unresolved, the P1839 code can impact fuel efficiency due to the transmission not functioning optimally. Addressing the issue promptly can help prevent further fuel consumption issues.