Fuel System Monitor

FUEL SYSTEM MONITOR

The fuel system monitor is an on-board strategy designed to monitor and detect concerns within the fuel control system and its components. The fuel control system uses fuel trim tables stored in the powertrain control module (PCM) keep alive memory (KAM) to compensate for the variability that occurs in fuel system components due to normal wear and aging. During certain driving conditions the PCM cycles the fuel pump on and off for testing purposes and is considered normal operation. The following functional checks and component monitors are executed during the fuel system monitor:
- fuel rail pressure (FRP) sensor circuit check
- FRP operation monitor
- FRP functional check
- fuel volume control valve operation monitor
- fuel pressure control valve operation monitor
- fuel injector driver operation monitor
- fuel injector circuit check

Diagnostic trouble codes (DTCs) P0192, P0193 and P0194: The FRP sensor circuit check runs continuously whenever the key is in ON position or the engine is running. The typical monitoring duration for this check varies from 0.1 to 0.5 seconds. During this check the PCM monitors the FRP sensor and related circuitry for out of range low and out of range high voltages. The PCM also monitors the absolute value of fuel pressure rate of change and compares it to the calibrated value.

DTCs P0087 and P0088: The FRP operation monitor runs continuously whenever the engine is running. The typical monitoring duration is 5 seconds. During this operation the PCM checks if the actual fuel pressure deviates from the desired fuel pressure, by the calibrated value, while the fuel pressure control valve and fuel volume control valve have reached their minimum or maximum operational limit.

DTC P0191: The FRP functional check runs continuously whenever engine is running in part load and the FRP is at least 10 MPa (1,450 psi). The typical monitoring duration for this check is 1 second. During this check the PCM monitors the minimum and maximum FRP over the calibrated time.

DTC P2289: The FRP functional check runs continuously whenever engine has just been turned off and the key is in OFF position. The typical monitoring duration for this check is 0.4 seconds. During this check the PCM monitors the FRP shortly after the engine is turned off.

DTCs P0001, P0003 and P0004: The fuel volume control valve operation monitor runs continuously whenever the engine is running. The typical monitoring duration for this monitor is 0.5 seconds. During this operation the PCM monitors fuel volume control valve and related circuitry for continuity, out of range low and out of range high voltages.

DTCs P0090, P0091 and P0092: The fuel pressure control valve operation monitor runs continuously whenever the engine is running. The typical monitoring duration for this monitor is 0.5 seconds. During this operation the PCM monitors fuel pressure control valve and related circuitry for continuity, out of range low and out of range high voltages.

DTCs P062D and P062E: The fuel injector driver operation monitor runs continuously whenever the engine speed is above 150 RPM or once per drive cycle during certain engine conditions. The typical monitoring duration for this monitor varies between 1 and 5 seconds. During this test the PCM checks for fuel injector driver initialization, plausibility and initialization voltage errors. The PCM also monitors the injector voltage present during the main injection and end of main injection stages. The title for DTCs P062D and P062E refer to bank 1 and bank 2. Disregard the bank terminology in the DTC title. The DTC P062D when set, refers to cylinders 1, 4, 6, and 7. The DTC P062E when set, refers to cylinders 2, 3, 5, and 8.

DTCs P0201 through P0208: The fuel injector circuit check runs continuously whenever engine speed is above 150 RPM. The typical monitoring duration for this check varies between 1 and 3 seconds. During this operation the PCM checks if the main injection and end of main injection stages are present. The PCM also measures fuel injector charge and discharge time during the specified injection stage.

DTCs P1551 through P1558: The fuel injector circuit check runs continuously whenever engine speed is above 150 RPM. The typical monitoring duration for this check varies between 1 and 3 seconds. During this operation the PCM checks if the main injection and end of main injection stages are present. The PCM also checks main injection and end of main injection stage voltages and if there are any current errors reported by the fuel injector drivers.