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Tahoe / Yukon Service Manual

DTC P0090-P0092, P00C9, P00CA, P10E6-P10E8, P10EA, P163A, P163B, P2294-P2296,

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5410013 DTC P0090-P0092, P00C9, P00CA, P10E6-P10E8, P10EA, P163A, P163B, P2294-P2296, or P233A-P233C 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 P0090 Fuel Pressure Regulator Control Circuit DTC P0091 Fuel Pressure Regulator Control Circuit Low DTC P0092 Fuel Pressure Regulator Control Circuit High DTC P00C9 Fuel Pressure Regulator High Control Circuit Low DTC P00CA Fuel Pressure Regulator High Control Circuit High DTC P10E6 Fuel Pressure Regulator 3 High Control Circuit Low DTC P10E7 Fuel Pressure Regulator 3 High Control Circuit High DTC P10E8 Fuel Pressure Regulator Control Circuit Shorted DTC P10EA Fuel Pressure Regulator 3 Control Circuit Shorted DTC P163A Control Module Fuel Pressure Regulator Control System Circuitry Performance DTC P163B Control Module Fuel Pressure Regulator 2 Control System Circuitry Performance DTC P2294 Fuel Pressure Regulator 2 Control Circuit DTC P2295 Fuel Pressure Regulator 2 Control Circuit Low DTC P2296 Fuel Pressure Regulator 2 Control Circuit High DTC P233A Fuel Pressure Regulator 3 Control Circuit DTC P233B Fuel Pressure Regulator 3 Control Circuit Low DTC P233C Fuel Pressure Regulator 3 Control Circuit High Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Control Circuit Shorted to Control Circuit Signal Performan
Control — Terminal 1 @ Q18A Fuel Pressure Regulator 1 P0091, P00C9 P0090 P0092, P00CA P0091, P00C9 P163A
Control — Terminal 2 @ Q18A Fuel Pressure Regulator 1 P0091, P00C9, P10E8 P0090 P0092, P00CA P10E8 P163A
Control — Terminal 1 @ Q18B Fuel Pressure Regulator 2 P2295 P2294. P2295 P0690, P16B3, P2296 P2295 P163B, P2293
Control — Terminal 2 @ Q18B Fuel Pressure Regulator 2 P2295 P2294. P2295 P0690, P16B3, P2296 P2295 P163B, P2293
Control — Terminal 1 @ Q18C Fuel Pressure Regulator 3 P10E6, P233B P233A P10E7, P233C P10E6, P233B P163A
Control — Terminal 2 @ Q18C Fuel Pressure Regulator 3 P10E6, P10EA, P233B P233A P10E7, P233C P10EA P163A

Typical Scan Tool Data Fuel Pressure Regulator Control Circuit High Test Status & Fuel Pressure Regulator 2, 3 Control Circuit High Test Status

Circuit Short to Ground Open Short to Voltage Control Circuit Shorted to Control Circuit
Operating Conditions: Engine Cranking or Engine Running Parameter Normal Range: Not Run or Okay
Control — Terminal 1 Okay Okay Malfunction Okay
Control — Terminal 2 Okay Okay Okay Okay

Fuel Pressure Regulator Control Circuit Low Test Status & Fuel Pressure Regulator 2, 3 Control Circuit Low Test Status

Circuit Short to Ground Open Short to Voltage Control Circuit Shorted to Control Circuit
Operating Conditions: Engine Cranking or Engine Running Parameter Normal Range: Not Run or Okay
Control — Terminal 1 Malfunction Okay Okay Okay
Control — Terminal 2 Okay Okay Okay Okay

Fuel Pressure Regulator Control Circuit Open Test Status & Fuel Pressure Regulator 2, 3 Control Circuit Open Test Status

Circuit Short to Ground Open Short to Voltage Control Circuit Shorted to Control Circuit
Operating Conditions: Engine Cranking or Engine Running Parameter Normal Range: Not Run or Okay
Control — Terminal 1 Okay Malfunction Okay Okay
Control — Terminal 2 Okay Okay Okay Okay

Fuel Pressure Regulator Control Circuit Shorted Test Status & Fuel Pressure Regulator 3 Control Circuit Shorted Test Status

Circuit Short to Ground Open Short to Voltage Control Circuit Shorted to Control Circuit
Operating Conditions: Engine Cranking or Engine Running Parameter Normal Range: Not Run or Okay
Control — Terminal 1 Okay Okay Okay Okay
Control — Terminal 2 Okay Okay Okay Malfunction

Fuel Pressure Regulator High Control Circuit High Test Status & Fuel Pressure Regulator 3 High Control Circuit High Test Status

Circuit Short to Ground Open Short to Voltage Control Circuit Shorted to Control Circuit
Operating Conditions: Engine Cranking or Engine Running Parameter Normal Range: Not Run or Okay
Control — Terminal 1 Okay Okay Okay Okay
Control — Terminal 2 Okay Okay Malfunction Okay

Fuel Pressure Regulator High Control Circuit Low Test Status & Fuel Pressure Regulator 3 High Control Circuit Low Test Status

Circuit Short to Ground Open Short to Voltage Control Circuit Shorted to Control Circuit
Operating Conditions: Engine Cranking or Engine Running Parameter Normal Range: Not Run or OK
Control — Terminal 1 Okay Okay Okay Okay
Control — Terminal 2 Malfunction Okay Okay Okay

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

Circuit Description
Control — Terminal 1 The output circuit is switched to ground to activate the component. The output is PWM controlled.
Control — Terminal 2 The output circuit is switched to 12 V to activate the component. The output is PWM controlled.
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.
Component Description
Q18A Fuel Pressure Regulator 1 & Q18C Fuel Pressure Regulator 3 The fuel pressure regulator is a solenoid valve that restricts the flow of fuel to the high pressure fuel pump and thereby controls the pressure the pump can produce.
Q18B Fuel Pressure Regulator 2 The fuel pressure regulator is the solenoid valve that controls the pressure in the fuel rail.

Conditions for Running the DTC P0090–P0092, P00C9, P00CA, P10E6–P10E8, P233A–P233C Engine = Not cranking Engine = Running Ignition and Start Signal = Greater than 11 V Frequency the DTC runs = Continuously — After the running conditions are met P163A DTC P0090, P0091, P0092 = Not set Fuel Rail Pressure is being controlled by Fuel Pressure Regulator 1 & 3. Ignition and Start Signal = Greater than 11 V Frequency the DTC runs = Continuously — After the running conditions are met P163B DTC P2294, P2295, P2296 = Not set Fuel Rail Pressure is being controlled by Fuel Pressure Regulator 2. Ignition and Start Signal = Greater than 11 V Frequency the DTC runs = Continuously — After the running conditions are met P2294–P2296 Engine = Not cranking Fuel Rail Pressure is being controlled by Fuel Pressure Regulator 2. Ignition and Start Signal = Greater than 6 V Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC P0090–P0092, P00C9, P00CA, P10E6–P10E8, P10EA, P2294–P2296, P233A–P233C Control Circuit = Commanded state does not match the actual state — For greater than 1 s P163A Condition 1 Q18A Fuel Pressure Regulator 1 — Electrical Current = Not within a calibrated range — For less than 1 s Condition 2 Q18A Fuel Pressure Regulator 1 — Control Circuit = High Resistance — For less than 1 s P163B Condition 1 Q18B Fuel Pressure Regulator 2 — Electrical Current = Not within a calibrated range — For less than 2 s Condition 2 Q18B Fuel Pressure Regulator 2 — Control Circuit = High Resistance — For less than 2 s Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type A DTC — Exceptions listed below DTC P163A, P163B = Type B DTC Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type A DTC — Exceptions listed below DTC P163A, P163B = Type B DTC Diagnostic Aids High resistance in the circuits of the component Q18A/Q18B/Q18C may set DTC P163A, P163B without setting control circuit DTC(s). 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 P0689, P0690, P1682 is not set. ⇒ If any of the DTCs are set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If none of the DTCs are set
  1. Perform the appropriate scan tool control function: Fuel Pressure Regulator 1, 2 » On and Off Verify the appropriate scan tool parameter: Fuel Pressure Regulator Control Circuit High Test Status & Fuel Pressure Regulator 2, 3 Control Circuit High Test Status = Not Run or Okay Fuel Pressure Regulator Control Circuit Low Test Status & Fuel Pressure Regulator 2, 3 Control Circuit Low Test Status = Not Run or Okay Fuel Pressure Regulator Control Circuit Open Test Status & Fuel Pressure Regulator 2, 3 Control Circuit Open Test Status = Not Run or Okay Fuel Pressure Regulator Control Circuit Shorted Test Status & Fuel Pressure Regulator 3 Control Circuit Shorted Test Status = Not Run or Okay Fuel Pressure Regulator High Control Circuit High Test Status & Fuel Pressure Regulator 3 High Control Circuit High Test Status = Not Run or Okay Fuel Pressure Regulator High Control Circuit Low Test Status & Fuel Pressure Regulator 3 High Control Circuit Low Test Status = Not Run or Okay ⇒ If not the specified state Refer to: Circuit/System Testing ⇓ If the specified state
  2. 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: Circuit/System Testing ⇓ If the DTC does not set
  3. All OK. Circuit/System Testing
  4. Ignition/Vehicle » Off
  5. Disconnect the appropriate electrical connector: Q18 Fuel Pressure Regulator
  6. Connect a test lamp between the test points: Control circuit terminal 1 & B+
  7. Ignition » On / Vehicle » In Service Mode
  1. Perform the appropriate scan tool control function: Fuel Pressure Regulator or Fuel Pressure Regulator 2 » On and Off Verify the test lamp turns On and changes brightness. ⇒ If the test lamp is always Off 5.1. Ignition/Vehicle » Off & Remove » Test lamp 5.2. Disconnect the electrical connector: X2 @ K20 Engine Control Module 5.3. Ignition » On / Vehicle » In Service Mode 5.4. Test for less than 1 V between the test points: Control circuit terminal 1 @ Component harness & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇓ If less than 1 V 5.5. Ignition/Vehicle » Off 5.6. Test for less than 2 Ω between the test points: Control circuit terminal 1 @ Component harness & The other end of the circuit @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K20 Engine Control Module ⇒ If the test lamp turns On but does not change brightness 5.1. Ignition/Vehicle » Off & Remove » Test lamp 5.2. Disconnect the appropriate electrical connector: X2 @ K20 Engine Control Module 5.3. Test for infinite resistance between the test points: Control circuit terminal 1 @ Component harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇒ If infinite resistance » Replace the component: K20 Engine Control Module ⇓ If the test lamp turns On and changes brightness
  2. Connect a test lamp between the test points: Control circuit terminal 1 & Control circuit terminal 2
  1. Perform the appropriate scan tool control function: Fuel Pressure Regulator or Fuel Pressure Regulator 2 » On and Off Verify the test lamp turns On and changes brightness. ⇒ If the test lamp is always Off 7.1. Ignition/Vehicle » Off & Remove » Test lamp 7.2. Disconnect the electrical connector: X2 @ K20 Engine Control Module 7.3. Test for infinite resistance between the test points: Control circuit terminal 2 @ Component harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance 7.4. Test for less than 2 Ω between the test points: Control circuit terminal 2 @ Component harness & The other end of the circuit @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K20 Engine Control Module ⇒ If the test lamp turns On but does not change brightness 7.1. Ignition/Vehicle » Off & Remove » Test lamp 7.2. Disconnect the electrical connector: X2 @ K20 Engine Control Module 7.3. Ignition » On / Vehicle » In Service Mode 7.4. Test for less than 1 V between the test points: Control circuit terminal 2 @ Component harness & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇒ If less than 1 V » Replace the component: K20 Engine Control Module ⇓ If the test lamp turns On and changes brightness
  2. Test or replace the component: Q18 Fuel Pressure Regulator Component Testing
  3. Ignition/Vehicle » Off
  4. Disconnect the appropriate electrical connector: Q18 Fuel Pressure Regulator
  1. Test for 0.3 to 2.0 Ω between the test points: Component terminal 1 & Component terminal 2 ⇒ If not between 0.3 and 2.0 Ω Replace the component: Q18 Fuel Pressure Regulator ⇓ If between 0.3 and 2.0 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: Q18 Fuel Pressure Regulator ⇓ If infinite resistance
  3. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification High Pressure Diesel Fuel Injection Rail Replacement — Q18B Fuel Pressure Regulator 2 High Pressure Diesel Fuel Pump Replacement — Q18A Fuel Pressure Regulator 1 & Q18C Fuel Pressure Regulator 3 For control module replacement, programming, and setup refer to: Control Module References