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Tahoe / Yukon Service Manual

DTC P026E, P10BA, P2B83, P2B84, P30AE, P30AF, U02A9, or U05AA

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5501060 DTC P026E, P10BA, P2B83, P2B84, P30AE, P30AF, U02A9, or U05AA 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 P026E Charge Air Cooler Coolant Pump Performance DTC P10BA Charge Air Cooler Coolant Pump Speed Performance DTC P2B83 Charge Air Cooler Coolant Pump Overspeed DTC P2B84 Charge Air Cooler Coolant Pump Underspeed DTC P30AE Charge Air Cooler Coolant Pump High Current DTC P30AF Charge Air Cooler Coolant Pump Low Current DTC U02A9 Lost Communication with Charge Air Cooler Coolant Pump DTC U05AA Invalid Data Received from Charge Air Cooler Coolant Pump Circuit/System Description For an overview of the component/system, refer to: Compressor Air Intake Turbocharger System Description

Circuit Description
B+ Supplied from a fuse.
Serial Data Digitally encoded information for communication between devices.
Ground Chassis Ground
Component Description
K20 Engine Control Module The control module contains a microprocessor used to process input data to control outputs. 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
Component Description
sensors, interprets the data and adjusts the engine actuators accordingly.
M10 Charge Air Cooler Coolant Pump The pump is driven by a 12 V DC motor.

Conditions for Running the DTC P026E, P10BA, P2B83, P2B84 Ignition and Start Switch Signal = On Ignition and Start Signal = Greater than 11 V Engine Coolant Pump Speed = Commanded On Charge Air Cooler Coolant Pump Speed = Greater than 1,000 RPM Engine Coolant Temperature = 40 to 104°C (126 to 258°F) Frequency the DTC runs = Continuously — After the running conditions are met P30AE, P30AF DTC U02A9 = Not set Ignition and Start Switch Signal = On » Engine Running Ignition and Start Signal = Greater than 11 V Frequency the DTC runs = Continuously — After the running conditions are met U02A9, U05AA Ignition and Start Switch Signal = On Ignition and Start Signal = Greater than 11 V Power Mode = Run Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC P026E, P10BA, P2B83, P2B84 Charge Air Cooler Coolant Pump Speed ≠ Desired Charge Air Cooler Coolant Pump Speed — For greater than 20 s P30AE, P30AF Charge Air Cooler Coolant Pump Current = Greater than a predefined threshold or Less than a predefined threshold — For greater than 4 s U02A9, U05AA Serial Data circuit = Message Counter Incorrect /Too Few Pulses /Too Many Pulses — For greater than 5 s 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 Heating/Cooling 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 » Idling — At normal operating temperature
  2. Verify DTC U02A9, U1348 is not set and no other DTCs are set. ⇒ If DTC U02A9, U1348 is set and no other DTCs are set Refer to: Circuit/System Testing ⇓ If DTC U02A9, U1348 is not set and other DTCs are set
  3. Perform the scan tool control function: Charge Air Cooler Coolant Pump » Command the component to the maximum position/speed — For greater than 180 s Verify the scan tool parameter: Charge Air Cooler Coolant Pump Dry = No Charge Air Cooler Coolant Pump Overtemperature = No Charge Air Cooler Coolant Pump Stalled = No Charge Air Cooler Coolant Pump Speed = Desired Charge Air Cooler Coolant Pump Speed ⇒ If not the specified state 3.1. Ignition/Vehicle & All vehicle systems » Off 3.2. Verify the following conditions do not exist: M10 Charge Air Cooler Coolant Pump Coolant = Correct level / Concentration Correct — Refer to: Charge Air Cooling System Draining and Filling Leaking — Refer to: Loss of Coolant Motor — Stuck Off / Restricted / Binding or Sticking — Worn Visible Damage ⇒ If a condition exists » Repair or replace as necessary ⇒ If no condition exists » Replace the component: M10 Charge Air Cooler Coolant Pump ⇓ If the specified state
  4. Perform the scan tool control function: Charge Air Cooler Coolant Pump » Command the component to the maximum position/speed & Release Control Verify the scan tool parameter: Charge Air Cooler Coolant Pump Communication Status = Okay Charge Air Cooler Coolant Pump Supply Voltage Status = Okay Charge Air Cooler Coolant Pump Internal Status = Okay ⇒ If not the specified state Refer to: Circuit/System Testing ⇓ If the specified state
  5. Perform the scan tool control function: Charge Air Cooler Coolant Pump » Command the component to the maximum position/speed Perform the action while monitoring the parameter: Charge Air Cooler Coolant Pump Speed Wiggle the harness and connector: M10 Charge Air Cooler Coolant Pump — The value should not spike or drop out. Wiggle the harness and connector: K20 Engine Control Module — The value should not spike or drop out. ⇒ If the value spikes or drops out Repair as necessary » Wiring / Terminal(s) / Electrical Connector(s) ⇓ If the value does not spike or drop out
  6. 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 is not set
  7. All OK. Circuit/System Testing
  8. Ignition/Vehicle & All vehicle systems » Off
  9. Disconnect the electrical connector: M10 Charge Air Cooler Coolant Pump
  10. Test for less than 5 Ω between the test points: Ground terminal 4 & Ground ⇒ If greater than 5 Ω 3.1. Disconnect the ground connection: Chassis Ground 3.2. Test for less than 2 Ω between the test points: Ground terminal 4 Component harness & The other end of the circuit @ Ground Connection ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Repair the open/high resistance in the ground connection. ⇓ If less than 5 Ω
  11. Ignition » On / Vehicle » In Service Mode
  12. Verify a test lamp turns On between the test points: B+ circuit terminal 1 & Ground ⇒ If the test lamp does not turn On and the circuit fuse is OK 5.1. Ignition/Vehicle » Off & Remove » Test lamp 5.2. Test for less than 2 Ω between the test points: B+ circuit terminal 1 & Output terminal @ Fuse ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Verify the fuse is OK and there is voltage at the fuse. ⇒ If the test lamp does not turn On and the circuit fuse is open 5.1. Ignition/Vehicle » Off & Remove » Test lamp 5.2. Test for infinite resistance between the test points: B+ circuit terminal 1 & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇒ If infinite resistance » Replace the component: M10 Charge Air Cooler Coolant Pump ⇓ If the test lamp turns On
  13. Connect a DMM between the test points: Serial Data circuit terminal @ Component harness & Ground Verify the DMM displays between 3.5 and 12 V & Fluctuates ⇓ If less than 3.5 V and does not fluctuate 6.1. Ignition/Vehicle » Off 6.2. Disconnect the appropriate electrical connector: K20 Engine Control Module 6.3. Test for infinite resistance between the test points: Serial Data circuit terminal 2 @ Component harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance 6.4. Test for less than 2 Ω between the test points: Serial Data 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 greater than 12 V and does not fluctuate 6.1. Ignition/Vehicle » Off 6.2. Disconnect the appropriate electrical connector: K20 Engine Control Module 6.3. Ignition » On / Vehicle » In Service Mode 6.4. Test for less than 1 V between the test points: Serial Data 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 between 3.5 and 12 and fluctuates
  14. Test or replace the component: M10 Charge Air Cooler Coolant Pump Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Charge Air Cooler Coolant Pump Replacement — M10 Charge Air Cooler Coolant Pump For control module replacement, programming, and setup refer to: Control Module References