AutoCodes – GMC – P1178 GMC

P1178 GMC Code - Fuel Pump Driver Control Module Sensor 1 Internal Supply Circuit

Quick Answer

The Fuel Pump Power Control Module is in constant communication with the Engine Control Module (ECM) regarding the operating state of the fuel pump power control system. Common causes include Faulty Fuel Pump Power Control Module, Fuel Pump Power Control Module harness is open or shorted, Fuel Pump Power Control Module 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: P1178 GMC indicates Fuel Pump Driver Control Module Sensor 1 Internal Supply Circuit.
Common causes: Common causes include Faulty Fuel Pump Power Control Module, Fuel Pump Power Control Module harness is open or shorted, Fuel Pump Power Control Module 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 770

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 Jul 24, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1178 GMC Description

The Fuel Pump Power Control Module is in constant communication with the Engine Control Module (ECM) regarding the operating state of the fuel pump power control system. Serial data messages are sent in a continuously repeating series of rolling counts with associated password protect samples. Each count/sample is assigned a value. When the ECM determines there is an error in the fuel pump control module fuel level sensor internal supply circuit, the ECM sets Diagnostic Trouble Code (DTC) P1178.

OBDII Code P1178 GMC - Fuel Pump Driver Control Module Sensor 1 Internal Supply Circuit - AutoCodes.com — P1178 GMC Code - Fuel Pump Driver Control Module Sensor 1 Internal Supply Circuit

What does this mean?

What are the Possible Causes of the DTC P1178 GMC?

Faulty Fuel Pump Power Control Module
Fuel Pump Power Control Module harness is open or shorted
Fuel Pump Power Control Module circuit poor electrical connection

How to Fix the DTC P1178 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 P1178 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.

Need more information about the P1178 GMC code?

Need more information on how to fix the P1178 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1178 GMC code diagnosed by a professional: Find a repair shop in your area

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 P1178 GMC Code

1. What are common symptoms of OBDII code P1178 in a GMC related to the Fuel Pump Driver Control Module Sensor 1 Internal Supply Circuit?

- Common symptoms include engine stalling, rough idling, and difficulty starting the vehicle.

2. What are potential causes of OBDII code P1178 in a GMC?

- Potential causes include a faulty fuel pump driver control module, wiring issues, or a malfunctioning sensor.

3. How can I diagnose the cause of OBDII code P1178 in my GMC?

- Diagnose the issue by checking the fuel pump driver control module, inspecting the wiring for damage, and testing the sensor's functionality.

4. Can a DIY enthusiast repair OBDII code P1178 in a GMC?

- While some DIY enthusiasts may be able to address this code by replacing the sensor or checking for wiring issues, it's recommended to consult a professional for accurate diagnosis and repair.

5. Is it safe to continue driving my GMC with OBDII code P1178 present?

- It is not recommended to drive your GMC with this code present, as it can lead to potential engine performance issues and safety concerns.

6. How much does it typically cost to repair OBDII code P1178 in a GMC?

- The cost of repairing this code can vary depending on the underlying cause, but it may range from $200 to $500 or more, including parts and labor.

7. Can OBDII code P1178 be triggered by a loose gas cap in a GMC?

- No, OBDII code P1178 is related to the fuel pump driver control module sensor and internal supply circuit, not a loose gas cap.

8. Will resetting the OBDII system clear the P1178 code in a GMC?

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

9. How urgent is it to address OBDII code P1178 in a GMC?

- It is important to address this code promptly to prevent potential damage to the fuel system and ensure the vehicle's proper operation.

10. Can a mechanic use a scan tool to diagnose OBDII code P1178 in a GMC?

- Yes, a mechanic can use a scan tool to retrieve the specific diagnostic trouble code (DTC) P1178 and further diagnose the issue with the fuel pump driver control module sensor 1 internal supply circuit.