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Tahoe / Yukon Service Manual

DTC P1006, P100F, P2B58, P2B59, P2B5B, or P2B5C

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5471891 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 P1006 Engine Coolant Flow Control Valve Control Circuit Shorted DTC P100F Engine Coolant Flow Control Valve Driver Temperature Too High DTC P2B58 Engine Coolant Flow Control Valve Current Too High DTC P2B59 Engine Coolant Flow Control Valve Control Circuit DTC P2B5B Engine Coolant Flow Control Valve Control Circuit High DTC P2B5C Engine Coolant Flow Control Valve Supply Voltage Circuit Low Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performanc
Control — Terminal 1 P1006, P2B59, P2B5C P2B5E, P2B59, U063F P1006, P2B59, P2B5B —
Control — Terminal 2 P1006, P2B59, P2B5C P2B5E, P2B59, U063F P1006, P2B59, P2B5B —

Circuit/System Description For an overview of the component/system, refer to: Cooling System Description and Operation

Circuit Description
Control — Terminal 1 The output circuit is switched from ground to 12 V to activate the component.
Control — Terminal 2 The output circuit is switched from ground to 12 V to activate the component.
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 sensors, interprets the data and adjusts the engine actuators accordingly.
Q97M Engine Coolant Flow Control Valve - Main The component is actuated by a bidirectional DC motor. Q97M is part of the component: Q97 Engine Coolant Flow Control Valve

To achieve the normal operating temperature faster, an actuator valve can block the coolant flow through the engine block. Conditions for Running the DTC Ignition/Vehicle = On Ignition Voltage = Greater than 11 V Frequency the DTC runs = Continuously — After the running conditions are met — For greater than 4 s Conditions for Setting the DTC P1006 Control Circuit = Shorted P100F Control module K20 detects: = Control Circuit — Warmer than 105°C (221°F) P2B58 Control Circuit = High Current P2B59, P2B5B, P2B5C Control Circuit = Voltage Out of Range — For greater than 2.5 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. Ignition » On / Vehicle » In Service Mode
  2. Verify DTC U063F is not set. ⇒ If DTC U063F is set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If DTC U063F is not set
  3. Perform the scan tool control function: Engine Coolant Flow Control Valve » Increase & Decrease Verify the scan tool parameter: Engine Coolant Control Valve Control Circuit High Test Status = Not Run or OK Engine Coolant Control Valve Control Circuit Low Test Status = Not Run or OK Engine Coolant Control Valve Control Circuit Open Test Status = Not Run or OK Engine Coolant Control Valve Control Circuit Shorted Test Status = Not Run or OK ⇒ If not the specified state Refer to: Circuit/System Testing ⇓ If the specified state
  4. Perform the action while monitoring the parameter: Engine Coolant Control Valve Control Circuit High Test Status = Not Run or OK Engine Coolant Control Valve Control Circuit Low Test Status = Not Run or OK Engine Coolant Control Valve Control Circuit Open Test Status = Not Run or OK Engine Coolant Control Valve Control Circuit Shorted Test Status = Not Run or OK – Wiggle the harness and connector: Q97 Engine Coolant Flow Control Valve – Wiggle the harness and connector: K20 Engine Control Module ⇒ If not the specified state Repair as necessary » Wiring / Terminal(s) / Electrical Connector(s) ⇓ If the specified state
  5. 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
  6. All OK. Circuit/System Testing
  7. Ignition/Vehicle » Off
  1. Disconnect the electrical connector: Q97M Engine Coolant Flow Control Valve - Main
  2. Ignition » On / Vehicle » In Service Mode
  3. Test for 8 to 10 V between the test points: Control circuit terminal 1 @ Component harness & Ground Control circuit terminal 2 @ Component harness & Ground ⇒ If less than 8 V 4.1. Ignition/Vehicle » Off 4.2. Disconnect the appropriate electrical connector: K20 Engine Control Module 4.3. Test for infinite resistance between the test points: Control circuit terminal 1 @ Component harness & Ground Control circuit terminal 2 @ Component harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance 4.4. Test for infinite resistance between the test points: Control circuit terminal 1 & Control circuit terminal 2 @ Component harness ⇒ If less than infinite resistance » Repair the short between the circuits. ⇓ If infinite resistance 4.5. Test for less than 2 Ω between the test points: Control circuit terminal 1 @ Component harness & Ground Control circuit terminal 2 @ Component harness & Ground ⇒ 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 10 V 4.1. Ignition/Vehicle » Off 4.2. Disconnect the appropriate electrical connector: K20 Engine Control Module 4.3. Ignition » On / Vehicle » In Service Mode 4.4. Test for less than 1 V between the test points: Control circuit terminal 1 @ Component harness & Ground 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 between 8 and 10 V
  4. Connect a test lamp between the test points: Control circuit terminal 1 & Control circuit terminal 2
  5. Perform the scan tool control function: Engine Coolant Control Valve » Increase
  6. Verify the test lamp turns On. ⇒ If the test lamp does not turn On 7.1. Ignition/Vehicle » Off & Remove » Test lamp 7.2. Disconnect the appropriate electrical connector: K20 Engine Control Module 7.3. Test for less than 2 Ω between the test points: Control circuit terminal 1 @ Component harness & Ground Control circuit terminal 2 @ Component harness & Ground ⇒ 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
  7. Test or replace the component: Q97M Engine Coolant Flow Control Valve - Main Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Engine Coolant Flow Control Valve Replacement — Q97M Engine Coolant Flow Control Valve
  • Main For control module replacement, programming, and setup refer to: Control Module References