P2635 2017 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 2017 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.
Code P2635 2017 GMC Sierra Description
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.
What are the Possible Causes of the DTC P2635 2017 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 2017 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.
Code Tech Notes
- 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 2017 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 2017 GMC Sierra code?
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Frequently Asked Questions about P2635 2017 GMC Sierra Code
1. What does OBDII code P2635 mean on a 2017 GMC Sierra?
P2635 indicates a fuel pump flow performance issue, meaning the fuel pump may not be delivering the expected fuel flow to the engine.
2. What are the common symptoms of code P2635 in a 2017 GMC Sierra?
Symptoms may include difficulty starting the engine, reduced engine performance, stalling, rough idling, or the vehicle entering limp mode.
3. What are the possible causes of code P2635?
Causes can include a failing fuel pump, clogged fuel filter, faulty fuel pressure regulator, wiring or connection issues to the fuel pump, or a malfunctioning fuel pump control module.
4. Can driving with code P2635 damage my 2017 GMC Sierra?
Yes, driving with this code can lead to engine performance issues and potentially damage the engine or other fuel system components if not addressed promptly.
5. How is code P2635 diagnosed?
A technician will inspect fuel pump performance, check for clogged filters, test fuel pressure, examine wiring and connections, and scan for additional trouble codes.
6. Can a dirty fuel filter cause a P2635 code?
Yes, a clogged fuel filter can restrict fuel flow, leading to insufficient fuel delivery and triggering the P2635 code.
7. How do I fix code P2635 on my 2017 GMC Sierra?
Repairs may include replacing the fuel pump, cleaning or replacing the fuel filter, repairing wiring or connections, or replacing the fuel pump control module.
8. Is a fuel pump replacement always necessary for code P2635?
Not necessarily. The issue could be caused by a clogged filter, faulty wiring, or a control module issue. Proper diagnosis is essential to avoid unnecessary repairs.
9. How much does it cost to repair code P2635 on a GMC Sierra?
The cost can vary depending on the root cause. A fuel pump replacement may cost $500–$1,000, while simpler fixes like replacing a fuel filter or repairing wiring will be less expensive.
10. Can I clear the P2635 code without fixing the problem?
While you can clear the code with an OBDII scanner, it will likely return if the underlying issue is not resolved.
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