P1839 2018 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 2018 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.
Code P1839 2018 Chevrolet Silverado Description
What are the Possible Causes of the DTC P1839 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 P1839 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 P1839 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.
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Frequently Asked Questions about P1839 2018 Chevrolet Silverado Code
1. What does OBDII code P1839 mean on a 2018 Chevrolet Silverado?
P1839 indicates an "Internal Mode Switch 'C' Circuit Low Voltage," meaning the transmission control module (TCM) has detected a low voltage signal from the Internal Mode Switch (IMS) circuit 'C.'
2. What are the symptoms of code P1839 in a 2018 Chevy Silverado?
Common symptoms include the transmission being stuck in one gear, harsh shifting, the vehicle going into limp mode, or the check engine light being illuminated.
3. What causes the P1839 code on a 2018 Chevrolet Silverado?
The most common causes include a faulty Internal Mode Switch, damaged or corroded wiring or connectors, low transmission fluid, or a malfunctioning TCM.
4. How do I diagnose the P1839 code in my Silverado?
Start by checking the transmission fluid level and inspecting the IMS circuit wiring and connectors for damage or corrosion. Use a multimeter to test for proper voltage and continuity in the IMS circuit.
5. Can I drive my 2018 Silverado with the P1839 code?
It is not recommended to drive with this code, as the transmission may not shift properly, potentially causing further damage or unsafe driving conditions.
6. How do I fix a P1839 code on a 2018 Chevrolet Silverado?
Repairs may include replacing the Internal Mode Switch, repairing or replacing damaged wiring or connectors, or reprogramming/replacing the TCM if necessary.
7. Does the P1839 code require a TCM replacement?
Not always. While a faulty TCM can cause this code, most cases are resolved by repairing wiring or replacing the Internal Mode Switch.
8. How much does it cost to fix the P1839 code on a Silverado?
The repair cost can vary widely, ranging from $50 for simple wiring repairs to $1,000 or more if the TCM or Internal Mode Switch needs replacement.
9. Can low transmission fluid trigger the P1839 code?
Yes, low or contaminated transmission fluid can affect the operation of the Internal Mode Switch and lead to this code being set.
10. Is the P1839 code a common issue for 2018 Chevrolet Silverado trucks?
While not extremely common, it can occur, particularly in vehicles with high mileage or those exposed to harsh driving conditions.
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