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DTC P0253 or P0254 - LNP or LNQ

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

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

Ignition

P0253 00

P0253 00

-

-

Control

P0253 00

P0253 00

P0254 00

-

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

    • The ignition is ON or the engine is running.
    • The ignition voltage is less than 16 V.
    • The DTCs runs continuously once the above conditions are met.

Conditions for Setting the DTC

P0253

The ECM detects the fuel pressure regulator control circuit is shorted to ground for more than 1 second.

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 P0253 00 and P0254 00 are Type A DTCs.

Conditions for Clearing the DTC

DTC P0253 00 and P0254 00 are Type A DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

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, observe the DTC information with a scan tool. DTCs P0253 00 or P0254 00 should not set.
  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.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the Q18 Fuel Pressure Regulator.
  2. Ignition ON, verify a test lamp illuminates between the ignition voltage circuit terminal 2 and ground.
  3. If the test lamp does not illuminate, repair the ignition voltage circuit for a short to ground or an open/high resistance.
  4. Ignition ON, test for 6.5-11 V between the control circuit terminal 1 and ground.
  5. If less than the specified range, test the control circuit for an open or a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.
    If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
  6. If all circuits test normal, test or replace the Q18 Fuel Pressure Regulator.

Component Testing

Static Test

  1. Ignition OFF, disconnect the harness connector at the Q18 Fuel Pressure Regulator.
  2. Test for 6-7 Ω between the control terminal 1 and the ignition voltage terminal 2.
  3. If not within the specified range, replace the Q18 Fuel Pressure Regulator.
  4. Test for infinite resistance between each terminal and the Q18 Fuel Pressure Regulator housing.
  5. If not the specified value, replace the Q18 Fuel Pressure Regulator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Fuel Injection Pump Replacement
    • Control Module References for ECM replacement, programming and setup
   


© Copyright Chevrolet. All rights reserved
   


© Copyright Chevrolet. All rights reserved