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Tahoe / Yukon Service Manual

DTC P020A-P020F

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5398958 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 P020A Cylinder 1 Fuel Injection Timing DTC P020B Cylinder 2 Fuel Injection Timing DTC P020C Cylinder 3 Fuel Injection Timing DTC P020D Cylinder 4 Fuel Injection Timing DTC P020E Cylinder 5 Fuel Injection Timing DTC P020F Cylinder 6 Fuel Injection Timing Circuit/System Description For an overview of the component/system, refer to: Fuel System Description

Circuit Description
Control circuit terminal 1 The output circuit is switched to 50 V to activate the component.
Control circuit terminal 2 The output circuit is switched to ground to activate the component.
Component Description
K20 Engine Control Module The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly.
Q17 Fuel Injector Fuel injectors are solenoid valves that inject fuel either into the intake system or directly into the cylinder. The amount of fuel injected depends on the length of the electrical pulse that is applied.

Conditions for Running the DTC DTC P0201–P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P062B, P062D, P1248–P124D, P2147, P2148, P2150, P2151, P2153, P2154 = Not set Battery Voltage = Greater than 11 V Engine = Running Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC The time to build up sufficient current to open the injector is below or above a predetermined threshold. Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type A DTC Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type A 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. Engine running.
  2. Verify there are no DTCs set related to the following component/system: Q17 Fuel Injector ⇒ If a related DTC is set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If a related DTC is not set
  3. 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.
  4. Verify the DTC does not set. ⇒ If the DTC sets Refer to: Circuit/System Testing ⇓ If the DTC does not set
  5. All OK. Circuit/System Testing
  6. Ignition/Vehicle » Off
  7. Disconnect the electrical connector: X160 Inline Harness Connector
  8. Ignition » On / Vehicle » In Service Mode
  1. Test for 16 V (±3 V) between the test points: { Q17A Fuel Injector 1 } Control circuit terminal 1 & Ground { Q17B Fuel Injector 2 } Control circuit terminal 3 & Ground { Q17C Fuel Injector 3 } Control circuit terminal 5 & Ground { Q17D Fuel Injector 4 } Control circuit terminal 7 & Ground { Q17E Fuel Injector 5 } Control circuit terminal 9 & Ground { Q17F Fuel Injector 6 } Control circuit terminal 11 & Ground ⇒ If not the specified value Refer to: DTC P0201-P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P1248-P124D, P2147, P2148, P2150, P2151, P2153, or P2154 ⇓ If the specified value
  2. Test for 0.20 V (±0.17 V) between the test points: { Q17A Fuel Injector 1 } Control circuit terminal 2 & Ground { Q17B Fuel Injector 2 } Control circuit terminal 4 & Ground { Q17C Fuel Injector 3 } Control circuit terminal 6 & Ground { Q17D Fuel Injector 4 } Control circuit terminal 8 & Ground { Q17E Fuel Injector 5 } Control circuit terminal 10 & Ground { Q17F Fuel Injector 6 } Control circuit terminal 12 & Ground ⇒ If not the specified value Refer to: DTC P0201-P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P1248-P124D, P2147, P2148, P2150, P2151, P2153, or P2154 ⇓ If the specified value
  1. Test for less than 3 Ω between the test points: { Q17A Fuel Injector 1 } Control circuit terminal 1 & Control circuit terminal 2 { Q17B Fuel Injector 2 } Control circuit terminal 3 & Control circuit terminal 4 { Q17C Fuel Injector 3 } Control circuit terminal 5 & Control circuit terminal 6 { Q17D Fuel Injector 4 } Control circuit terminal 7 & Control circuit terminal 8 { Q17E Fuel Injector 5 } Control circuit terminal 9 & Control circuit terminal 10 { Q17F Fuel Injector 6 } Control circuit terminal 11 & Control circuit terminal 12 ⇒ If 3 Ω or greater 6.1. Verify a condition does not exist with the component: Q17 Fuel Injector » Refer to: Component Testing ⇒ If a condition exists » Replace the component: Q17 Fuel Injector ⇒ If no condition exists » Repair the open/high resistance in the circuit. ⇓ If less than 3 Ω
  2. Test or replace the component: Q17 Fuel Injector Component Testing
  3. Ignition/Vehicle » Off
  4. Disconnect the electrical connector: Q17 Fuel Injector
  1. Test for 0.2 to 1.5 Ω between the test points: Component terminal 1 & Component terminal 2 ⇒ If not between 0.2 and 1.5 Ω Replace the component: Q17 Fuel Injector ⇓ If between 0.2 and 1.5 Ω
  2. Test for infinite resistance between the test points: Each terminal of the component & The component’s housing ⇒ If less than infinite resistance Replace the component: Q17 Fuel Injector ⇓ If infinite resistance
  3. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification High Pressure Diesel Fuel Injector Replacement For control module replacement, programming, and setup refer to: Control Module References