DTC P0251-P0254
| DTC P0251-P0254 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptor |
DTC P0251 00
Fuel Pressure Regulator Control Circuit Malfunction
DTC P0252 54
Fuel Pressure Regulator Performance
DTC P0253 00
Fuel Pressure Regulator Control Circuit Low Voltage
DTC P0254 00
Fuel Pressure Regulator Control Circuit High Voltage
| Diagnostic Fault Information |
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
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Ignition
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P0253 00
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P0251 00
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-
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P0252 54
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Control
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P0253 00
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P0251 00
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P0254 00
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P0252 54
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| Circuit/System Description |
The fuel pressure regulator is used to control the fuel pressure at the high pressure pump. The fuel pressure regulator is pulse width modulated (PWM). The engine control module (ECM) supplies the voltage directly to the fuel pressure regulator. The ECM controls the solenoid by grounding the control circuit with a solid state device called a driver.
| Conditions for Running the DTC |
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The ignition is ON or the engine is running.
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The ignition voltage is less than 16 V.
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The DTCs run continuously when the above conditions are met.
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| Conditions for Setting the DTC |
P0251
The ECM detects the Fuel Pressure Regulator Control Circuit is open for more than 1 s.P0252 54
The ECM detects an overtemperature at the output control driver of the fuel pressure regulator.P0253
The ECM detects the fuel pressure regulator control circuit is shorted to ground for more than 1 s.P0254
The ECM detects the fuel pressure regulator control circuit is shorted to voltage for more than 1 s.| Action Taken When the DTC Sets |
DTC P0251, P0252 54, P0253 and P0254 are type A DTCs.
| Conditions for Clearing the DTC |
DTC P0251, P0252 54, P0253 and P0254 are type A DTCs.
| Reference Information |
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Fuel System Description
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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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, check the diagnostic trouble code (DTC) information with a scan tool. DTC P0251, P0252 54, P0253 or P0254 must not be set.
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| 2. |
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
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| Circuit/System Testing |
| 1. |
Ignition OFF, disconnect the harness connector at the listed below.
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LCD, LBX, LBS Q45 Fuel Rail Pressure Regulator
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LBY Q45A Fuel Rail Pressure Regulator 1
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| 2. |
Ignition ON, verify a test lamp illuminates between the ignition voltage circuit terminal listed below and ground.
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LCD, LBX, LBS Terminal 1
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LBY Terminal 2
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| 3. |
If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If circuit tests normal, replace the K20 Engine Control Module.
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| 4. |
Ignition ON, test for 3-4 V between the control circuit terminal listed below and ground.
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LCD, LBX, LBS Terminal 2
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LBY Terminal 1
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| 5. |
If less than the specified range, test the control circuit for an open or a short to ground. If circuit tests normal, replace the K20 Engine Control Module.
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| 6. |
If greater than the specified range, test the control circuit for a short to voltage. If circuit tests normal, replace the K20 Engine Control Module.
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| 7. |
Test for less than 5 Ω on the ignition voltage circuit, and the control circuit.
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| 8. |
If greater than the specified range, repair the appropriate circuit for a high resistance.
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| 9. |
If all circuits test normal, test or replace the component listed below.
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LCD, LBX, LBS Q45 Fuel Rail Pressure Regulator
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LBY Q45A Fuel Rail Pressure Regulator 1
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| Component Testing |
Static Test
| 1. |
Ignition OFF, disconnect the harness connector at the component listed below.
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LCD, LBX, LBS Q45 Fuel Rail Pressure Regulator
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LBY Q45A Fuel Rail Pressure Regulator 1
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| 2. |
Test for 2.5-3.5 Ω between the control terminal 2 and the ignition voltage terminal 1.
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| 3. |
If not within the specified range, replace the Fuel Pressure Regulator.
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| 4. |
Test for infinite resistance between each terminal and the solenoid Fuel Pressure Regulator housing.
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| 5. |
If not the specified value, replace the Fuel Pressure Regulator.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for ECM replacement, setup, and programming
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