Engine-CodesGMC – P182C 2018 GMC Sierra

P182C 2018 GMC Sierra Code - Internal Mode Switch 'B' Circuit High Voltage

Quick Answer

The P182C diagnostic trouble code (DTC) for a 2018 GMC Sierra refers to an issue with the Internal Mode Switch 'B' Circuit High Voltage. Common causes include Faulty Internal Mode Switch, Damaged wiring connecting the switch to the TCM, Short circuit in the circuit. 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
P182C 2018 GMC Sierra indicates Internal Mode Switch 'B' Circuit High Voltage.
Common causes
Common causes include Faulty Internal Mode Switch, Damaged wiring connecting the switch to the TCM, Short circuit in the circuit.
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.
Table of contents Created and updated by William Orellana on Sep 27, 2024
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Code P182C 2018 GMC Sierra Description

The P182C diagnostic trouble code (DTC) for a 2018 GMC Sierra refers to an issue with the Internal Mode Switch 'B' Circuit High Voltage. The Internal Mode Switch (IMS) is a component of the transmission control system that helps the vehicle's computer determine the current gear selection. In this case, the 'B' circuit is reporting a higher voltage than expected, indicating a potential problem with the switch or its wiring.

OBDII Code P182C 2018 GMC Sierra - Internal Mode Switch 'B' Circuit High Voltage
P182C 2018 GMC Sierra Code - Internal Mode Switch 'B' Circuit High Voltage

Common Causes of P182C 2018 GMC Sierra

  1. Faulty Internal Mode Switch
  2. Damaged wiring connecting the switch to the TCM
  3. Short circuit in the circuit
  4. Problem with the TCM

Symptoms of P182C 2018 GMC Sierra

  1. Erratic shifting patterns
  2. Harsh shifts
  3. Transmission getting stuck in a gear
  4. Hesitation during acceleration
  5. Poor fuel efficiency

How to Fix P182C 2018 GMC Sierra

  1. Begin by conducting a thorough inspection of the Internal Mode Switch and its wiring to identify any visible damage or issues.
  2. Use a multimeter to test the voltage output of the 'B' circuit to determine if it is indeed reporting high voltage.
  3. If the IMS is faulty, replace it with a new one following the manufacturer's guidelines.
  4. Repair any damaged wiring or connectors in the circuit to ensure proper electrical connections.
  5. Clear the DTC from the vehicle's computer using a diagnostic scan tool and test drive the vehicle to confirm that the issue has been resolved.

Cost to Fix P182C 2018 GMC Sierra

The typical repair costs for addressing the Internal Mode Switch 'B' Circuit High Voltage issue can vary depending on the extent of the problem and the specific components that need to be replaced. In general, the cost of replacing the Internal Mode Switch and repairing any damaged wiring can range from $200 to $500, including parts and labor. However, it's important to note that diagnostic time and labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more accurate estimate based on your location and vehicle specifics.

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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 P182C 2018 GMC Sierra Code

1. What does the OBDII code P182C mean on a 2018 GMC Sierra?

P182C indicates a problem with the Internal Mode Switch (IMS) 'B' Circuit reporting high voltage, which can affect the transmission's ability to detect shift positions correctly.

2. What are the common symptoms of code P182C on a GMC Sierra?

Common symptoms include the transmission staying in a single gear, inability to shift properly, a check engine light, and erratic or hard shifting.

3. What causes the P182C code to appear?

Causes can include a faulty internal mode switch, damaged wiring or connectors in the IMS circuit, a short circuit, or a malfunctioning transmission control module (TCM).

4. Can I drive my 2018 GMC Sierra with the P182C code?

Driving with this code is not recommended, as it may lead to further transmission issues, reduced performance, and potential safety concerns.

5. How do I diagnose the P182C code on a GMC Sierra?

Diagnosis involves checking the IMS wiring and connectors for damage, testing the internal mode switch for proper function, and using a multimeter to verify circuit voltage levels.

6. How is the P182C code fixed?

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

7. What tools are needed to troubleshoot the P182C code?

You'll need an OBDII scanner, a multimeter for voltage testing, and possibly a repair manual or wiring diagram specific to the 2018 GMC Sierra.

8. How much does it cost to fix the P182C code on a GMC Sierra?

The cost varies depending on the issue. Replacing an internal mode switch may cost $200-$500, while wiring repairs or TCM replacement could increase the total cost.

9. Can a dirty transmission fluid cause the P182C code?

While dirty transmission fluid is unlikely to directly cause P182C, it can contribute to transmission issues that may trigger related codes or symptoms.

10. Is the P182C code covered under warranty for my 2018 GMC Sierra?

It may be covered if your vehicle is still under the powertrain warranty. Check with your dealership to confirm warranty coverage.

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