Print 1Search REQUESTED INFORMATION Dtc Diagnostic Instructions 2012 Chevrolet Silverado 6.6L Eng 2500 Hd Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach. Diagnostic Procedure Instructions provides an overview of each diagnostic category. Dtc Descriptor DTC Performance Diagnostic Fault Information Circuit Short to Ground Open/High Resistance Short to Signal Performanc e Solenoid Supply P125 A P2294 P125 B P0087. P0088. Sensor 5 Volt Reference P0193, P0641 P0191 P0193, P0641 P0191 Sensor Signal P0192 P0193 P0193 P0191
Solenoid Low Reference P2295 P2294 P2296 P0087. P0088, Low Reference - P0191 1 P0191 1 Opens circuit fuse or opens circuit. Typical Scan Tool Data Sensor Circuit Short to Ground Open Short to Operating Conditions: Ignition ONParameter Normal Range: 30-219 MPa (4350-31, 763 psi) Sensor Signal Circuit/System Description 0 MPa (0.0 psi) 219 MPa (31, 763 psi) 219 MPa (31, 763 psi) During certain engine operating conditions the engine control module (ECM) checks the actual fuel rail pressure reported from the fuel rail pressure sensor and compares the value to a set programed value. If the values are out of the calibrated range for a set amount of time DTC will set. Conditions For Running The Dtc Fuel tank level is greater than 15 % Engine is in crank or run mode Conditions For Setting The Dtc Actual fuel rail pressure is below 15 MPa (2175 psi) for greater than 2 s. Actual fuel rail pressure exceeds 215 MPa (31, 183 psi) for greater than 1 s. Action Taken When The Dtc Sets DTC is a Type A DTC. The ECM commands the engine to operate in the Reduced Engine
Power mode. The message center displays Reduced Engine Power. Conditions For Clearing The Mil/Dtc DTC is a Type A DTC. Diagnostic Aids Water in fuel system may cause this DTC to intermittently to set. Refer to Contaminants-in-Fuel Diagnosis Gasoline in fuel system may cause this DTC to set. When power enhancing devices have been attached to the fuel rail pressure sensor circuits, this DTC may set and adversely affect the fuel system components. The addition of fuel system enhancements, such as auxiliary fuel tanks or add on fuel filters may relate to driveability complaints. Reference Information Schematic Reference Engine Controls Schematics Connector End View Reference WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX Description and Operation Fuel System Description Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs DTC Type Reference Powertrain Diagnostic Trouble Code (DTC) Type Definitions Scan Tool Reference Control Module References for scan tool information Circuit/System Verification 1 Ignition ON. 2 Observe the DTC information with a scan tool. Verify no other DTCs are set. If another DTC set Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis. If another DTC did not set
3 Observe the Sensor parameter with a scan tool. During engine cranking, the pressure should be greater than 13 MPa (1885 psi). If 13 MPa (1885 psi) or less Refer to Circuit/System Testing. If greater than 13 MPa (1885 psi) 4 Observe the Sensor parameter with a scan tool, at idle the pressure should be close to the Desired. As the engine speed increases, the Desired and the Actual should closely match each other. If pressure does not closely match Refer to Circuit/System Testing. If pressure closely matches 5 Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data. If DTC sets Refer to Circuit/System Testing. If DTC does not set 6 All OK. Circuit/System Testing 1 NOTE: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing. At idle fuel pressure regulator 2 is used to maintain the desired fuel pressure, if fuel pressure regulator 2 is leaking the actual pressure will be at least 690 kpa (100 psi) below the desired fuel pressure. Running the engine above 1700 RPM switches the fuel pressure control mode to fuel pressure regulator 1. If fuel pressure regulator 1 is leaking or binding the fuel pressure will fluctuate above and below the desired fuel pressure by greater than 690 kpa (100 psi). 2 3 Review the freeze frame data and compare to the conditions to set this DTC. If fuel pressure was low when DTC set Refer to Fuel System Diagnosis - High Pressure Side. If fuel pressure was not low when DTC set 4 NOTE: This procedure must be performed at idle and at 1800 RPM. 5 Engine at idle, command the fuel pressure incrementally through the entire fuel pressure range with a scan tool. The Actual Fuel Rail
Pressure and the Desired should be within 690 kpa (100 psi) for the entire fuel pressure range. If the desired and actual fuel pressure at idle is within 690 kpa (100 psi) and was not within 690 kpa (100 psi) at 1800 RPM Replace the Q45A Fuel Pressure Regulator 1. If the desired and actual fuel pressure at idle was not within 690 kpa (100 psi) but was within 690 kpa (100 psi) at 1800 RPM Replace the Q45B Fuel Pressure Regulator 2. If the desired and actual fuel pressure was not within 690 kpa (100 psi) at idle or at 1800 RPM Replace both Q45A Fuel Pressure Regulator 1 and Q45B Fuel Pressure Regulator 2. Inspect the fuel system for contamination, refer to Contaminants-in-Fuel Diagnosis. If the desired and actual fuel pressure at idle is within 690 kpa (100 psi) and was within 690 kpa (100 psi) at 1800 RPM 6 All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Fuel Pressure Relief Valve Replacement Perform the scan tool Diesel Particulate Filter (DPF) Regeneration Enable, procedure if the scan tool DPF Soot Mass is less than 30 g. If the scan tool DPF Soot Mass is 30 g or greater, perform the Diesel Particulate Filter (DPF) Service Regeneration procedure. Control Module References for ECM replacement, programming, and setup.