DTC P2B5E, P2B5F, or U063F

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5512374 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 P2B5E Engine Coolant Flow Control Valve Position Sensor Circuit Low DTC P2B5F Engine Coolant Flow Control Valve Position Sensor Circuit High DTC U063F Lost Communication with Coolant Diverter Valve Actuator Circuit/System Description For an overview of the component/system, refer to: Cooling System Description and Operation

Circuit	Description
5 V Reference	Regulated voltage supplied by the control module.
Serial Data	Digitally encoded information for communication between devices.
Low Reference	Grounded through the control module.

Component	Description
Q97M Engine Coolant Flow Control Valve - Main	The component is actuated by a bidirectional DC motor.
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.

To achieve the normal operating temperature faster, an actuator valve can block the coolant flow through the engine block. Conditions for Running the DTC P2B5E, P2B5F DTC U063F = Not set Ignition = On Ignition and Start Switch Signal = Greater than 11 V Frequency the DTC runs = Continuously — After the running conditions are met U063F Ignition = On Ignition and Start Switch Signal = Greater than 11 V Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC P2B5E Engine Coolant Flow Control Valve Position Sensor = Low Voltage P2B5F Engine Coolant Flow Control Valve Position Sensor = High Voltage U063F Engine Coolant Flow Control Valve Position Sensor = Lost Communication with Engine Control Module 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 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

1. Ignition » On / Vehicle » In Service Mode
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 no DTC is set
3. All OK. Circuit/System Testing

Note

It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

1. Ignition/Vehicle & All vehicle systems » Off
2. Disconnect the electrical connector: Q97M Engine Coolant Flow Control Valve - Main
3. Test for less than 10 Ω between the test points: Low Reference circuit terminal 5 & Ground ⇒ If 10 Ω or greater 3.1. Disconnect the appropriate electrical connector: @ K20 Engine Control Module 3.2. Test for less than 2 Ω between the test points: Low Reference circuit terminal 5 @ 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 less than 10 Ω
4. Ignition » On / Vehicle » In Service Mode
5. Test for 4.8 to 5.2 V between the test points: 5 V Reference circuit terminal 3 & Low Reference circuit terminal 5 ⇒ If less than 4.8 V 5.1. Ignition/Vehicle » Off 5.2. Disconnect the appropriate electrical connector: @ K20 Engine Control Module 5.3. Test for infinite resistance between the test points: 5 V Reference circuit terminal 3 @ Component harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance 5.4. Test for less than 2 Ω between the test points: 5 V Reference circuit terminal 3 @ 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 5.2 V 5.1. Ignition/Vehicle » Off 5.2. Disconnect the appropriate electrical connector: @ K20 Engine Control Module 5.3. Ignition » On / Vehicle » In Service Mode 5.4. Test for less than 1 V between the test points: 5 V Reference circuit terminal 3 @ 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 4.8 and 5.2 V
6. Test for 4.8 to 5.2 V between the test points: Signal circuit terminal 4 & Ground ⇓ If less than 4.8 V 6.1. Disconnect the appropriate electrical connector: @ K20 Engine Control Module 6.2. Test for infinite resistance between the test points: Signal circuit terminal 4 @ Component harness & Ground ⇒ If less than infinite resistance Repair the short to ground on the circuit: ⇓ If infinite resistance 6.3. Test for infinite resistance between the test points: Signal circuit terminal 4 @ Component harness & Low Reference circuit terminal 5 @ Component harness ⇒ 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: Signal circuit terminal 4 @ 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 5.2 V 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: Signal circuit terminal 4 @ 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 4.8 and 5.2 V
7. 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

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