2009 Chevrolet Silverado P0641, P06A6, and P069E Codes: Fuel System & Starting Issues Explained
I own a 2009 Chevrolet Silverado with the check engine light illuminated. My OBD2 scan tool shows three diagnostic trouble codes: P0641 (5-volt reference voltage incorrect), P06A6, and P069E (Fuel Pump Control Module requests MIL illumination). These codes are also flagged as 'pending,' indicating they may have been detected recently but not yet resolved. In addition to the codes, I've noticed a recurring issue: my truck will not start on the first attempt. I must turn the key off and then try starting it again—after that second attempt, it starts immediately every time. This behavior occurs intermittently, which makes me suspect an underlying electronic or fuel system fault. I'm looking for confirmation whether this combination of codes has been seen before in similar vehicles. Before replacing parts blindly, I'd like to understand the root causes and proper diagnostic steps. Any insights would be greatly appreciated.
What engine configuration do you have? Is your vehicle stock? Fuel pressure issues are a common concern in this scenario. I recommend starting with a fuel pressure test—this will help identify whether the problem lies in the fuel delivery system. The Fuel Pump Control Module (FPCM) is a key component in modern electronic returnless fuel systems (ERFS). It's a serviceable GMLAN device that regulates voltage to the fuel pump inside the tank, ensuring proper fuel pressure as requested by the Engine Control Module (ECM). Fuel Pump Control Module DTC P069E: - The FPCM stores diagnostic data. If a fault is detected, it sends a signal to the ECM to illuminate the Malfunction Indicator Lamp (MIL), triggering DTC P069E. - However, specific faults are stored within the FPCM itself and must be retrieved using the FPCM menu on a Tech 2 scan tool. Potential causes include: - Electrical wiring or connector issues in the FPCM circuit - Internal failure of the FPCM module - Faulty fuel line pressure sensor - Malfunctioning fuel pump MRA (Motor Resistance Assembly) - Communication errors between the FPCM and ECM Tip: When using a scan tool like Tech 2, if DTC P069E is detected, navigate to the Powertrain menu and select 'Fuel Pump Control Module' for deeper diagnostics. This will reveal stored faults and allow you to assess fuel pressure performance. Note: The FPCM is often overlooked during fuel system troubleshooting. A DIY scanner or basic OBD2 tool may not access FPCM-specific codes—professional-grade tools like Tech 2 are typically required.