DTC P109F, P10A0-P10A2, or P26B7-P26B9
Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5501827 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 P109F Engine Coolant Control Valve Supply Voltage Circuit Low DTC P10A0 Engine Coolant Control Valve Current Too High DTC P10A1 Engine Coolant Control Valve Actuator Control Circuit Shorted DTC P10A2 Engine Coolant Control Valve Driver Temperature Too High DTC P26B7 Engine Coolant Control Valve Actuator Control Circuit Diagnostic Fault Information
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performanc |
|---|---|---|---|---|
| Control — Terminal 1 | P10A1, P26B8, P26BB | P26B7, P26B9, P26BB | P10A0, P10A1, P26B7, P26B9, P26BB | P26BB |
| Control — Terminal 2 | P10A1, P26B8, P26BB | P26B7, P26B9 | P10A0, P10A1, P26B7, P26B9, P26BB, P0690 | P26BB |
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 |
|---|---|
| Q74 Engine Coolant Bypass Valve | The component is actuated by a bidirectional DC motor. Q74 is part of the component: Q97 Engine Coolant Flow Control Valve |
| 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. |
Conditions for Running the DTC Ignition/Vehicle = On Ignition and Start Switch Signal = 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 P109F, P26B7, P26B8, P26B9 Control Circuit = Voltage Out of Range — For greater than 2.5 s P10A0 Control Circuit = High Current P10A1 Control Circuit = Shorted P10A2 Control module K20 detects: = Control Circuit — Warmer than 105°C (221°F) 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
- Ignition » On / Vehicle » In Service Mode
- Verify DTC U0617 is not set. ⇒ If DTC U0617 is set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If DTC U0617 is not set
- 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
- All OK. Circuit/System Testing
- Ignition/Vehicle » Off
- Disconnect the electrical connector: Q74 Engine Coolant Bypass Valve
- Ignition » On / Vehicle » In Service Mode
- Test for battery voltage between the test points: Control circuit terminal 1 @ Component harness & Ground Control circuit terminal 2 @ Component harness & Ground ⇒ If not the specified value 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 4.5. Ignition/Vehicle » Off 4.6. 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 4.7. 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 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 specified value
- Test or replace the component: Q74 Engine Coolant Bypass Valve Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Engine Coolant Flow Control Valve Replacement — Q74 Engine Coolant Bypass Valve For control module replacement, programming, and setup refer to: Control Module References