P1840 2014 Chevrolet Silverado Code - Internal Mode Switch 'S' 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
- P1840 2014 Chevrolet Silverado indicates Internal Mode Switch 'S' 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 P1840 2014 Chevrolet Silverado Description
What are the Possible Causes of the DTC P1840 2014 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 P1840 2014 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 P1840 2014 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 P1840 2014 Chevrolet Silverado Code
1. What does OBDII code P1840 mean on a 2014 Chevrolet Silverado?
Code P1840 indicates that the Internal Mode Switch (IMS) 'S' circuit is experiencing low voltage, which can affect the transmission's ability to detect the correct gear position.
2. What are common symptoms of code P1840 in a 2014 Chevy Silverado?
Symptoms may include erratic shifting, the transmission stuck in one gear, the check engine light illuminated, and reduced vehicle performance.
3. What causes P1840 in a 2014 Chevrolet Silverado?
The most common causes include a faulty Internal Mode Switch, damaged wiring or connectors in the IMS circuit, or a transmission control module (TCM) issue.
4. Can I drive my 2014 Chevy Silverado with a P1840 code?
While the vehicle may still be drivable, continuing to drive with this code can lead to further transmission damage and unsafe driving conditions. It’s recommended to address the issue promptly.
5. How is P1840 diagnosed on a 2014 Chevrolet Silverado?
A mechanic will use a scan tool to confirm the code, inspect the IMS circuit for damaged wiring or poor connections, and test the IMS for proper operation.
6. How do you fix code P1840 on a 2014 Chevy Silverado?
Repairs may involve replacing the Internal Mode Switch, repairing or replacing damaged wiring or connectors, or reprogramming or replacing the transmission control module if necessary.
7. What is the Internal Mode Switch in a 2014 Chevy Silverado?
The Internal Mode Switch is a sensor in the transmission that communicates the gear position to the vehicle’s computer system to ensure proper operation.
8. How much does it cost to repair P1840 in a 2014 Chevrolet Silverado?
Repair costs can vary, but replacing the Internal Mode Switch typically ranges from $200 to $500, depending on labor rates and parts availability.
9. Can a low battery cause P1840 in a 2014 Chevy Silverado?
While unlikely, a weak or failing battery can sometimes contribute to electrical issues, including triggering low voltage-related codes like P1840.
10. Is P1840 a common issue in the 2014 Chevrolet Silverado?
P1840 is not a widespread issue but can occur over time, especially in vehicles with higher mileage or those exposed to harsh operating conditions.
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