AutoCodes – Chevrolet – P18C1 2016 Chevrolet Silverado

P18C1 2016 Chevrolet Silverado Code - Internal Mode Switch 'C' Circuit Stuck On Invalid Voltage Range

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: P18C1 2016 Chevrolet Silverado indicates Internal Mode Switch 'C' Circuit Stuck On Invalid Voltage Range.
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 297

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 P18C1 2016 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 has an invalid voltage range of 0.70 – 0.96 V, for 2.7 s.

OBDII Code P18C1 2016 Chevrolet Silverado - Internal Mode Switch 'C' Circuit Stuck On Invalid Voltage Range - AutoCodes.com — P18C1 2016 Chevrolet Silverado Code - Internal Mode Switch 'C' Circuit Stuck On Invalid Voltage Range

What does this mean?

What are the Possible Causes of the DTC P18C1 2016 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 P18C1 2016 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 P18C1 2016 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 P18C1 2016 Chevrolet Silverado code?

Need more information on how to fix the P18C1 2016 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 P18C1 2016 Chevrolet Silverado Code

1. What are the common symptoms of OBDII code P18C1 in a 2016 Chevrolet Silverado?

- Common symptoms include issues with shifting gears, poor acceleration, and the transmission not responding as expected.

2. What does the OBDII code P18C1 'Internal Mode Switch 'C' Circuit Stuck On Invalid Voltage Range' mean for a 2016 Chevrolet Silverado?

- This code indicates a problem with the internal mode switch 'C' circuit in the transmission, specifically related to an invalid voltage range being detected.

3. What are the possible causes of the Internal Mode Switch 'C' Circuit Stuck On Invalid Voltage Range OBDII code in a 2016 Chevrolet Silverado?

- Potential causes include a faulty internal mode switch, damaged wiring or connectors, low transmission fluid levels, or issues with the transmission control module.

4. How can I diagnose the Internal Mode Switch 'C' Circuit Stuck On Invalid Voltage Range issue in my 2016 Chevrolet Silverado?

- Diagnosis typically involves using a scan tool to check for the specific trouble code, inspecting the internal mode switch and related components, and testing the circuit for voltage irregularities.

5. Are there any safety concerns associated with driving a 2016 Chevrolet Silverado with OBDII code P18C1?

- It is recommended to address the issue promptly to avoid potential transmission-related problems that could impact the vehicle's performance and safety.

6. Can I continue driving my 2016 Chevrolet Silverado with the Internal Mode Switch 'C' Circuit Stuck On Invalid Voltage Range code?

- It is not advisable to continue driving the vehicle with this code present, as it can lead to further transmission issues and potentially cause damage.

7. What are some repair tips for fixing the Internal Mode Switch 'C' Circuit Stuck On Invalid Voltage Range problem in a 2016 Chevrolet Silverado?

- Repair tips may include checking and repairing any damaged wiring, replacing the internal mode switch if necessary, ensuring proper transmission fluid levels, and resetting the trouble code after making repairs.

8. How much does it typically cost to repair the OBDII code P18C1 in a 2016 Chevrolet Silverado?

- The cost of repair can vary depending on the exact cause of the issue, but it may involve parts replacement and labor costs that can range from a few hundred to over a thousand dollars.

9. Can I reset the Internal Mode Switch 'C' Circuit Stuck On Invalid Voltage Range code in my 2016 Chevrolet Silverado myself?

- While you can attempt to clear the trouble code using an OBDII scanner, it is important to address the underlying issue causing the code to prevent it from reoccurring.

10. How can I prevent the Internal Mode Switch 'C' Circuit Stuck On Invalid Voltage Range code from appearing in my 2016 Chevrolet Silverado in the future?

- Regular maintenance checks, including inspecting the transmission components and addressing any issues promptly, can help prevent the recurrence of this code.