2010 Cadillac Truck SRX AWD V6-3.0L Page 1309
瀚慖f less than specified range, test the signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the
K20 ECM.
瀚慖f greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
6. Install a 3 A fused jumper wire between TP sensor 1 signal circuit terminal D and the 5 V reference circuit terminal E. Verify the scan tool
TP sensor 1 voltage parameter is greater than 4.8 V.
瀚慖f less than the specified range, test the signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace
the K20 ECM.
7. If all circuits test normal, test or replace the Q38 throttle body assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the repair.
* Throttle Body Assembly Replacement (LF1) (See: Powertrain Management/Fuel Delivery and Air Induction/Throttle Body/Service and
Repair/Removal and Replacement)Throttle Body Assembly Replacement (LAU) (See: Powertrain Management/Fuel Delivery and Air
Induction/Throttle Body/Service and Repair/Removal and Replacement)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, programming, and setup
P228C
DTC P0089, P00C6, P228C, or P228D (LF1, LFW)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0089
- Fuel Pressure Regulator Performance
DTC P00C6
- Fuel Rail Pressure Low During Engine Cranking
DTC P228C
- Fuel Pressure Regulator 1 Control Performance - Low Pressure
DTC P228D
- Fuel Pressure Regulator 1 Control Performance - High Pressure
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
P0089, P228C, or P228D
