DTC P1093
Fuel Rail Pressure Low During Power Enrichment
The engine control module (ECM) uses the fuel rail pressure (FRP) sensor to
determine fuel pressure to the fuel injectors. This is then compared to the calculated
target fuel pressure as determined by the ECM. The ECM adjusts the FRP by modulating
the duty cycle of the control driver of the fuel pressure regulator. Injector pulse
duration is determined by the measured rail pressure and the target injection fuel
into each cylinder. If a sensor circuit malfunction is detected, or the commanded
fuel injection pump flow is not within the proper range for a given engine load and
speed, DTCs will be set.
DTC U1000 and U1255
Circuit Description Modules connected to the class 2 serial data circuit monitor for serial
data communications during normal vehicle operation. Operating information and
commands are exchanged among the modules. When a module receives a message for
a critical operating parameter, the module records the identification number of
the module which sent the message for State of Health monitoring. A critical
operating parameter is one which, when not received, requires that the module
use a default value for that parameter. When a module does not associate an identification
number with at least one critical parameter within about five seconds of beginning
serial data communication, DTC U1000 or U1255 is set. When more than one
critical parameter does not have an identification number associated with it, the
DTC will only be reported once. The class 2 serial data line on this vehicle
is a ring/star configuration. The following modules communicate on the class 2
serial data line:
•
The body control module (BCM)
•
The digital radio reciever
•
The driver door module (DDM)
•
The electronic brake control module (EBCM)
•
The front passenger door module (FPDM)
•
The HVAC control module
•
The inflatable restraint sensing and diagnostic module (SDM)
•
The instrument panel cluster (IPC)
•
The memory seat module (MSM)
•
The powertrain control module (PCM)
•
The radio
•
The radio amplifier
•
The rear seat audio (RSA) controller
•
The rear seat entertainment (RSE) assembly w/U42
•
The rear wheel steering control module
•
The remote playback device-CD player w/U1S
•
The transfer case shift control module
•
The transmission control module (TCM) w/Allison transmission
•
The theft deterrent control module
•
The vehicle communication interface module (VCIM) w/UE1
