2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 2603
Repairs/Wiring Repairs)
* Electrical Center Identification Views (See: Maintenance/Fuses and Circuit Breakers/Fuse/Application and ID)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Special Tools
J 43244 Relay Puller Pliers
Circuit/System Verification
1. Ignition OFF, open the hood to disable the Auto-Stop function. Refer to Hybrid Modes of Operation Description ( See: Hybrid Drive
Systems/Description and Operation/Hybrid Modes of Operation).
2. Ignition ON, verify the scan tool hood position parameter displays Open.
瀚慖f the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code
Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle) for DTC P254F.
3. Ignition ON, command the engine controls (EC) ignition relay ON and OFF, with a scan tool, while observing the EC ignition relay coil
control circuit status parameters listed below:
* EC Ignition Relay Ckt. Short Gnd Test Status
* EC Ignition Relay Ckt. Open Test Status
* EC Ignition Relay Ckt. Short Volts Test Status
Each parameter should display OK or Not Run in each commanded state
4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the
conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Note: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
1. Ignition OFF, disconnect the KR75 powertrain relay.
2. Verify a test lamp illuminates between both of the following relay battery voltage circuit terminals and ground:
* Terminal 85
* Terminal 30
瀚慖f the test lamp does not illuminate, test the relay battery voltage circuit for an open/high resistance ore a short to ground.
Note: The ignition voltage circuit is between the powertrain relay and the ECM. The ignition voltage is a feedback circuit.
3. Ignition OFF, verify that a test lamp does not illuminate between the ignition voltage circuit terminal 87 and ground.
瀚慖f the test lamp illuminates, test the ignition voltage circuit for a short to voltage.
4. Connect a 20 A fused jumper wire between the relay switch B+ circuit terminal 30 and the relay switch ignition voltage circuit terminal 87.
5. Ignition ON, observe the scan tool EC Ignition Relay Feedback Signal parameter. The ECM should communicate, and the parameter should
display B+.
瀚慖F not the specified value, or the ECM does not communicate, test the ignition voltage circuit between the powertrain relay and the ECM
for a short to ground or for an open/high resistance. If the circuit/connections test normal, replace the K20 ECM.
6. Ignition OFF, verify that a test lamp does not illuminate between the control circuit terminal 86 and B+.
瀚慖f the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
7. Connect a DMM set to the diode setting between the control circuit terminal 86 and ground.
8. Ignition ON, verify the DMM does not display OL.
瀚慖f the DMM displays OL, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the
K20 ECM.
9. If all circuits test normal, replace the KR75 powertrain relay.
