AutoCodes – GMC – P181E GMC

P181E GMC Code - Internal Mode Switch 2 R2 Circuit Low Voltage

Quick Answer

The automatic transmission manual shift shaft position switch assembly, also called the internal mode switch assembly, contains two sliding hall-effect switch assemblies attached to the control valve body within the transmission. Common causes include Faulty Manual Shift Shaft Position Switch Assembly, Manual Shift Shaft Position Switch Assembly harness is open or shorted, Manual Shift Shaft Position Switch Assembly 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: P181E GMC indicates Internal Mode Switch 2 R2 Circuit Low Voltage .
Common causes: Common causes include Faulty Manual Shift Shaft Position Switch Assembly, Manual Shift Shaft Position Switch Assembly harness is open or shorted, Manual Shift Shaft Position Switch Assembly 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 1,362

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 Jan 30, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P181E GMC Description

The automatic transmission manual shift shaft position switch assembly, also called the internal mode switch assembly, contains two sliding hall-effect switch assemblies attached to the control valve body within the transmission. The 9 outputs from the switches indicate which position is selected by the transmission manual shaft. Four outputs (A, B, C, P) are range selection inputs to the transmission control module (TCM). Five outputs (R1, R2, D1, D2, S) are direction selection inputs to the hybrid powertrain control module. The Range input signals are represented as TCM scan tool parameters, Internal Mode Switch A, B, C, and P. The Direction input signals are represented as hybrid powertrain control module scan tool parameters, Internal Mode Switch 2 - R1, R2, D1, D2, and S. The input voltage at the modules is high when a switch is open and low when a switch is closed to earth. Each control module independently supplies power and earth to its respective switch assembly.
The hybrid powertrain control module is internal to the power inverter module, often referred to as the drive motor generator power inverter module and is not serviced separately.

OBDII Code P181E GMC - Internal Mode Switch 2 R2 Circuit Low Voltage - AutoCodes.com — P181E GMC Code - Internal Mode Switch 2 R2 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P181E GMC?

Faulty Manual Shift Shaft Position Switch Assembly
Manual Shift Shaft Position Switch Assembly harness is open or shorted
Manual Shift Shaft Position Switch Assembly circuit poor electrical connection

How to Fix the DTC P181E GMC?

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 P181E GMC 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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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 P181E GMC Code

1. What are the common symptoms of OBDII code P181E GMC (Internal Mode Switch 2 R2 Circuit Low Voltage)?

The common symptoms of this code may include issues with shifting gears, transmission slipping, or difficulty engaging gears.

2. What can cause the OBDII code P181E GMC to appear?

The code P181E may be triggered by a faulty internal mode switch, a malfunctioning transmission range sensor, wiring issues, or a problem with the transmission control module.

3. How serious is the OBDII code P181E GMC?

The severity of this code can vary. While it may not always result in immediate drivability issues, it is important to address it promptly to prevent potential transmission problems.

4. How can I diagnose the OBDII code P181E GMC at home?

Diagnosing this code may require using an OBDII scanner to read the code and check for related transmission issues. However, comprehensive diagnosis and repair may be best handled by a professional mechanic.

5. Can I continue driving with the OBDII code P181E GMC present?

It is not recommended to continue driving with the code present, as it can lead to further damage to the transmission if left unaddressed.

6. What are some repair tips for fixing the OBDII code P181E GMC?

Repairing this code may involve replacing the internal mode switch, repairing or replacing damaged wiring, checking and calibrating the transmission range sensor, or reprogramming the transmission control module.

7. How much does it typically cost to repair the OBDII code P181E GMC?

The cost of repairing this code can vary depending on the specific underlying issue, the labor rates in your area, and whether you choose to have the repair done at a dealership or an independent repair shop.

8. Is there a way to prevent the OBDII code P181E GMC from appearing again in the future?

Regular maintenance of the transmission system, including checking for loose wiring or damaged components, can help prevent the recurrence of this code.

9. Can resetting the OBDII system clear the P181E GMC code?

Resetting the OBDII system may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear.

10. How long does it take to repair the OBDII code P181E GMC?

The repair time for this code can vary depending on the specific repairs needed and the availability of parts. It is advisable to consult with a mechanic for a more accurate estimate of repair time.