2010 Cadillac CTS Sedan AWD V6-3.6L Page 984
Circuit/System Description
The fuel rail pressure sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 V reference voltage on the 5
V reference circuit and ground on the low reference circuit. The ECM receives a varying signal voltage on the signal circuit.
High pressure fuel is regulated by the high pressure fuel pump actuator, which is a part of the high pressure fuel pump. The high pressure fuel pump
actuator is a solenoid valve. The ECM provides a voltage on the actuator high control circuit and ground on the actuator low control circuit. Both
circuits are controlled through output drivers within the ECM. When deactivated, both drivers are disabled. When activated, the high control circuit
driver energizes the high pressure fuel pump actuator and the low control circuit driver pulse-width modulates (PWM) the low control circuit to
ground.
The high pressure mechanical fuel pump is driven by three lobes on the camshaft. The ECM uses the camshaft and crankshaft position sensor inputs
to synchronize the high pressure fuel pump actuator with the position of each of the camshaft lobes. The ECM regulates fuel pressure by adjusting
the portion of each pump stroke that provides fuel to the rail.
The ECM monitors the fuel rail fuel pressure sensor and the high pressure fuel pump actuator to determine if the commanded and actual pressure
are within a predetermined range, or if the amount of fuel pressure correction exceeds a calibrated pressure.
Conditions for Running the DTC
* DTC P0090, P0091, P0092, P0191, P0192, or P0193 is not set.
* The ignition 1 signal parameter is between 10-18 V.
* The engine start temperature is greater than -48掳C (-54掳F).
* The fuel level is greater than 11 %.
* The deceleration fuel cut-off (DFCO) is inactive.
* The engine speed is greater than 600 RPM once during engine start for greater than 5 s.
* The air bag is not deployed.
* DTCs P0087, P0088, and P0089 run continuously when the above conditions are met for 5 s.
Conditions for Setting the DTC
P0087
The actual fuel rail pressure is 1 MPa (145 psi) less than the desired fuel pressure. The condition exists for greater than 5 s.
P0088
The actual fuel rail pressure is 2 MPa (290 psi) greater than the desired fuel rail pressure. The condition exists for greater than 5 s.
P0089
The high pressure fuel pump actuator command necessary to maintain the desired fuel rail pressure is +/-2 MPa (290 psi) of the command expected
by the controller. The condition exists for greater than 5 s.
Action Taken When the DTC Sets
* DTCs P0087, P0088, and P0089 are Type A DTCs.
* A message center or an indicator displays Reduced Engine Power.
Conditions for Clearing the DTC
DTCs P0087, P0088, and P0089 are Type A DTCs.
Diagnostic Aids
* A condition with the fuel tank fuel pump module or fuel pump flow control module will set these DTCs.
* A skewed fuel rail pressure sensor, or an intermittent condition in the fuel rail pressure sensor circuits may set these DTCs.
* A leaking or restricted fuel injector may set DTC P0089.
Reference Information
Schematic Reference
Engine Controls Schematics (LLT) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics
(LF1) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
