AutoCodes – GMC – P2635 2016 GMC Sierra

P2635 2016 GMC Sierra Code - Fuel Pump Flow Performance

Quick Answer

The Engine Control Module (ECM) supplies voltage to the fuel pump driver control module when the ECM detects that the ignition is on. Common causes include Faulty Fuel Pump, Fuel Pump harness is open or shorted, Fuel Pump 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: P2635 2016 GMC Sierra indicates Fuel Pump Flow Performance.
Common causes: Common causes include Faulty Fuel Pump, Fuel Pump harness is open or shorted, Fuel Pump 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 551

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 Apr 14, 2023

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P2635 2016 GMC Sierra Description

The Engine Control Module (ECM) supplies voltage to the fuel pump driver control module when the ECM detects that the ignition is on. The voltage from the ECM to the fuel pump driver control module remains active for 2 s unless the engine is in crank or run. While this voltage is being received, the fuel pump driver control module closes the ground switch of the fuel pump. The fuel pump driver control module maintains correct fuel pressure based on the information from the fuel pressure sensor and varies the pulse width modulated controlled current to the fuel pump.
The Diagnostic Trouble Code (DTC) will be set when the fuel pump driver control module detects a difference of ± 60 kPa (8.7 PSI) at 400 kPa (58 PSI) request or ±45 kPa (6.5 PSI) at 300 kPa (43.5 PSI) request between the desired fuel pressure and the actual fuel pressure for approximately 10 s.

OBDII Code P2635 2016 GMC Sierra - Fuel Pump Flow Performance - AutoCodes.com — P2635 2016 GMC Sierra Code - Fuel Pump Flow Performance

What does this mean?

What are the Possible Causes of the DTC P2635 2016 GMC Sierra?

Faulty Fuel Pump
Fuel Pump harness is open or shorted
Fuel Pump circuit poor electrical connection
Faulty Fuel Pump Control Module (if applicable)

How to Fix the DTC P2635 2016 GMC Sierra?

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 a Factory Service Bulletin for the following Chevrolet Models:

- 2014-2018 Chevrolet Silverado
- 2015-2018 Chevrolet Suburban
- 2015-2018 Chevrolet Tahoe

If the Diagnostic Trouble Codes (DTC) P2635, U0074, and/or U18A2 are set, it may be found that the actual fuel pressure (low-pressure system) will be reading substantially higher than desired fuel pressure, in this case, the cause of the problem is a loss of communication between Engine Control Module (ECM) and Fuel Pump Control Module (FPCM).

- Diagnose for any communication DTCs set (U0074 would take priority over U18A2 if both set) before addressing DTC P2635.
- If DTC P2635 is not resolved by correcting the communication DTCs, only then should diagnose the DTC P2635.
- It has been found that a communication issue between the FPCM and ECM can potentially induce DTC P2635 and result in a pressure differential between actual and desired fuel system pressures.
- If the actual fuel pressure is substantially higher than desired (10 psi / 70 kPa or more), replacement of the fuel pump control module or fuel system components typically will not resolve this issue.
- If the actual fuel pressure is substantially lower than desired (10 psi / 70 kPa or more), this Factory Service Bulletin would NOT apply. It would be recommended to diagnose low actual fuel pressure.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P2635 2016 GMC Sierra 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 P2635 2016 GMC Sierra 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 P2635 2016 GMC Sierra Code

1. What are the common symptoms of OBDII code P2635 in a 2016 GMC Sierra related to Fuel Pump Flow Performance?

- Common symptoms include poor engine performance, decreased fuel efficiency, and potential stalling or hesitation during acceleration.

2. What are the possible causes of OBDII code P2635 in a 2016 GMC Sierra indicating Fuel Pump Flow Performance issues?

- The code may be triggered by a clogged fuel filter, a failing fuel pump, restricted fuel lines, or issues with the fuel pressure sensor.

3. How can I diagnose the underlying issue causing OBDII code P2635 in my 2016 GMC Sierra related to Fuel Pump Flow Performance?

- Diagnosing the issue may involve checking the fuel pressure with a gauge, inspecting the fuel filter for blockages, and testing the fuel pump for proper function.

4. Can a dirty fuel system cause OBDII code P2635 in a 2016 GMC Sierra related to Fuel Pump Flow Performance?

- Yes, a dirty fuel system can restrict fuel flow and trigger the code. Regular maintenance, such as fuel system cleaning, can help prevent this issue.

5. What are some repair tips for addressing OBDII code P2635 in a 2016 GMC Sierra indicating Fuel Pump Flow Performance problems?

- Repair tips may include replacing the fuel filter, cleaning the fuel lines, inspecting the fuel pump for wear, and resetting the code after addressing the root cause.

6. Is it safe to continue driving my 2016 GMC Sierra with OBDII code P2635 related to Fuel Pump Flow Performance?

- It is not recommended to ignore the code and continue driving, as it can lead to further engine damage or safety hazards. Prompt diagnosis and repair are advised.

7. Can a faulty fuel pressure sensor trigger OBDII code P2635 in a 2016 GMC Sierra indicating Fuel Pump Flow Performance issues?

- Yes, a malfunctioning fuel pressure sensor can inaccurately detect fuel flow performance, leading to the triggering of the code. The sensor may need to be replaced.

8. Will resetting the OBDII code P2635 in my 2016 GMC Sierra related to Fuel Pump Flow Performance resolve the issue?

- Resetting the code may temporarily clear the warning, but it will not fix the underlying problem causing the code. Proper diagnosis and repair are necessary.

9. How can I prevent OBDII code P2635 related to Fuel Pump Flow Performance issues in my 2016 GMC Sierra?

- Regular maintenance, including fuel system inspections, filter replacements, and using quality fuel, can help prevent issues that trigger this code.

10. Can extreme weather conditions impact the triggering of OBDII code P2635 in a 2016 GMC Sierra related to Fuel Pump Flow Performance?

- Yes, extreme temperatures can affect fuel flow and pressure, potentially leading to issues that trigger the code. Ensuring proper maintenance is crucial in such conditions.