2010 Cadillac CTS Sedan AWD V6-3.6L Page 1451
Diagnostic Aids
* The scan tool cooling fan output control operates as follows:
- Cooling Fan Relay 1 operates the fan at a low speed
- Cooling Fan Relay 2 and 3 operates one fan at a high speed
- Cooling Fan Relay 1, 2 and 3 operates the fan at a high speed
* KR20 cooling fan relay identification:
- KR20C cooling fan low speed FAN 1 Relay
- KR20D cooling fan high speed FAN 2 Relay
- KR20E cooling fan speed control FAN 3 or S/P Relay
* When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the
correct orientation in the fuse block. Test the mating electrical terminals for tightness.
Reference Information
Schematic Reference
Engine Cooling Schematics (See: Engine, Cooling and Exhaust/Cooling System/Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Cooling System Description and Operation (LF1, LLT) (See: Engine, Cooling and Exhaust/Cooling System/Description and Operation)Cooling
System Description and Operation (LSA) (See: Engine, Cooling and Exhaust/Cooling System/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
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
Circuit/System Verification
1. Ignition ON, command the KR20 cooling fan relays ON and OFF with a scan tool. Listen or feel the relay click.
2. Ignition ON, observe the scan tool Cooling Fan Relay 1 and the Cooling Fan Relay 2 and 3 Control Circuit Test Status parameters. Command
the cooling fans ON and OFF with a scan tool. Verify all of the Cooling Fan Relay Control Circuit Test Status parameters display OK or Not
Run in each of the commanded states.
3. Engine operating, observe the DTC information with a scan tool. DTC P0480, P0481, P0691, P0692, P0693, or P0694 should not set.
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
1. Ignition OFF, disconnect all of the KR20 cooling fan relays.
Note: The following tests must be performed on all three fan relay circuits.
2. Ignition ON, verify that a test lamp illuminates between ground and the relay coil ignition circuit terminal listed below:
* KR20C cooling fan low speed relay terminal 85
* KR20D cooling fan high speed relay terminal 85
* KR20E cooling fan speed control relay terminal 86
瀚慖f the test lamp does not illuminate, test the relay coil ignition circuit for a short to ground or an open/high resistance. If the circuit tests
normal and the relay coil ignition circuit fuse is open, test all components connected to the ignition circuit and replace as necessary.
