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Tahoe / Yukon Service Manual

DTC P3187 or P3188

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5501805 Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC P3187 Fuel Pump Pressure Performance - Low Pressure DTC P3188 Fuel Pump Pressure Performance - High Pressure Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performanc
Control — Terminal 1 @ A7 Fuel Pump and Level Sensor Assembly P102A P1029 P102B P3187, P3188
Control — Terminal 2 @ A7 Fuel Pump and Level Sensor Assembly P102A P1029 P102B P3187, P3188
Control — Terminal 3 @ A7 Fuel Pump and Level Sensor Assembly P102A P1029 P102B P3187, P3188

Circuit/System Description For an overview of the component/system, refer to: Fuel System Description

Circuit Description
Control The output circuit varies between ground and 12 V.
Component Description
G12 Fuel Pump The component has a 3-phase motor. The control module converts the DC voltage from the battery to 3-phase AC to power the motor.
K111 Fuel Pump Power Control Module The control module K111 supplies the fuel pump with a PWM signal in order to achieve the desired fuel line pressure.

Conditions for Running the DTC DTC P018B, P018C, P018D, P0641, P064A, P0606, P1029, P102A, P102B, P102C, P1255, P129F, P12A6, P14D5, P165C, P2BB3, P20CD, U18A7 = Not set Fuel Pump Command = On Ignition and Start Signal = 11 to 32 V Engine Run Time = Greater than 30 s Fuel Level Sensor = Greater than 10% Frequency the DTC runs = Continuously — After the running conditions are met — For greater than 1 s Conditions for Setting the DTC The difference between the following parameters is greater than a predefined value: Desired Fuel Pressure Fuel Pressure Sensor Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type B DTC Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type B DTC Reference Information Schematic Reference Engine Controls Schematics Connector End View Reference Master Electrical Component List 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 Circuit/System Verification

  1. Ignition » On / Vehicle » In Service Mode
  2. Verify DTC U0074, U18A2 is not set as a history DTC. ⇒ If DTC U0074, U18A2 is set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If DTC U0074, U18A2 is not set
  3. Verify DTC P018B, P018C, P018D, P0231, P0232, P023F is not set. ⇒ If DTC P018B, P018C, P018D, P1029, P102A, P102B is set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If DTC P018B, P018C, P018D, P1029, P102A, P102B is not set
  4. Engine » Idling
  5. Perform the scan tool control function: Fuel Pressure » Increase & Decrease
  6. Verify the following parameters are within 45 kPa (6.5 PSI) of each other: Desired Fuel Pressure Fuel Pressure Sensor ⇒ If not within 45 kPa (6.5 PSI) of each other Refer to: Fuel System Diagnosis ⇓ If within 45 kPa (6.5 PSI) of each other
  7. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data. Verify the DTC does not set. ⇒ If the DTC sets Refer to: Fuel System Diagnosis ⇓ If the DTC does not set
  8. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification