DTC P1096, P1097, or U0617

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5501086 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 P1096 Engine Coolant Control Valve Position Sensor Circuit Low DTC P1097 Engine Coolant Control Valve Position Sensor Circuit High DTC U0617 Lost Communication with Engine Coolant Control Valve 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
K20 Engine Control Module	The control module contains a microprocessor used to process input data to control outputs.
Q74 Engine Coolant Bypass Valve	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. The component is actuated by a bidirectional DC motor. Q74 is part of the component: Q97 Engine Coolant Flow Control Valve

The valve controls the distribution of coolant through the following components: Engine Oil Cooler Radiator Transmission Fluid Cooler Conditions for Running the DTC P1096, P1097 DTC U0617 = Not set Ignition and Start Switch Signal = On Frequency the DTC runs = Continuously — After the running conditions are met U0617 Ignition and Start Switch Signal = On Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC P1096, P1097 Serial Data circuit = Not within a calibrated range U0617 Serial Data circuit = Current Out Of Range 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 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 U0617 is not set. ⇒ If DTC U0617 is set Refer to: Circuit/System Testing ⇓ If DTC U0617 is not set
3. 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
4. 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: Q74 Engine Coolant Bypass Valve
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 to 8 V between the test points: Signal circuit terminal 4 @ Component harness & Ground ⇒ If greater than 8 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 less than 4 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 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 between 4 and 8 V
7. 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