AutoCodes – GMC – C0300 GMC

C0300 GMC Code - Rear Propshaft Speed Sensor

Quick Answer

The rear propshaft speed sensor is a Permanent Magnet (PM) generator. Common causes include Faulty Rear Propshaft Speed Sensor, Rear Propshaft Speed Sensor harness is open or shorted, Rear Propshaft Speed Sensor 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: C0300 GMC indicates Rear Propshaft Speed Sensor.
Common causes: Common causes include Faulty Rear Propshaft Speed Sensor, Rear Propshaft Speed Sensor harness is open or shorted, Rear Propshaft Speed Sensor 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 20,748

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 Jun 18, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code C0300 GMC Description

The rear propshaft speed sensor is a Permanent Magnet (PM) generator. The PM generator produces a pulsing AC voltage. The AC voltage level and number of pulses increases as speed increases. The module converts the pulsating AC voltage to a propshaft RPM which is used for calculations. The propshaft RPM can be displayed with a scan tool.
This DTC detects an open, short to ground, short to voltage or faulty sensor.

OBDII Code C0300 GMC - Rear Propshaft Speed Sensor - AutoCodes.com — C0300 GMC Code - Rear Propshaft Speed Sensor

What does this mean?

What are the Possible Causes of the DTC C0300 GMC?

Faulty Rear Propshaft Speed Sensor
Rear Propshaft Speed Sensor harness is open or shorted
Rear Propshaft Speed Sensor circuit poor electrical connection

How to Fix the DTC C0300 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 does this mean?

Code Tech Notes

There is factory service bulletin for the C0300 code. The factory recommends reprogramming the Transfer Case Control Module (TCCOM) to fix the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C0300 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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Need Help with the Code?

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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 C0300 GMC Code

1. What are the common symptoms of OBDII code C0300 in a GMC related to the Rear Propshaft Speed Sensor?

- Common symptoms include issues with the vehicle's traction control system, ABS system, and potential drivability issues such as improper shifting.

2. What are the typical causes of OBDII code C0300 in a GMC specifically related to the Rear Propshaft Speed Sensor?

- The code C0300 is often triggered by a faulty rear propshaft speed sensor, damaged wiring or connectors, or issues with the sensor's signal.

3. How can I diagnose the OBDII code C0300 in a GMC related to the Rear Propshaft Speed Sensor?

- Diagnosis typically involves using a scan tool to retrieve the specific error code, checking the sensor and its wiring for damage, and testing the sensor's functionality.

4. What are some repair tips for resolving OBDII code C0300 in a GMC due to issues with the Rear Propshaft Speed Sensor?

- Repair tips may include replacing the rear propshaft speed sensor, repairing or replacing damaged wiring or connectors, and ensuring proper installation and calibration.

5. Can I drive my GMC with OBDII code C0300 related to the Rear Propshaft Speed Sensor?

- It is not recommended to drive the vehicle with this code present, as it can affect important systems like traction control and ABS, potentially compromising safety and drivability.

6. How much does it typically cost to repair OBDII code C0300 in a GMC caused by the Rear Propshaft Speed Sensor?

- Repair costs can vary depending on the exact cause of the issue, but replacing the rear propshaft speed sensor and addressing related wiring problems can range from $200 to $500.

7. Are there any preventive measures to avoid triggering OBDII code C0300 in a GMC due to the Rear Propshaft Speed Sensor?

- Regularly inspecting and maintaining the rear propshaft speed sensor, checking for any signs of damage or wear, and addressing issues promptly can help prevent this code from appearing.

8. Can weather conditions or rough terrain impact the Rear Propshaft Speed Sensor and trigger OBDII code C0300 in a GMC?

- Extreme weather conditions or rough terrain can potentially damage the rear propshaft speed sensor or its wiring, leading to the triggering of code C0300 in a GMC.

9. Will resetting the OBDII system clear the code C0300 related to the Rear Propshaft Speed Sensor in a GMC?

- Resetting the OBDII system may temporarily clear the code, but if the underlying issue with the rear propshaft speed sensor persists, the code is likely to reappear.

10. How long does it typically take to repair OBDII code C0300 in a GMC related to the Rear Propshaft Speed Sensor?

- The repair time can vary depending on the exact cause of the code and the extent of the repairs needed, but it typically takes a few hours to a full day to diagnose and fix the issue.