2010 Cadillac CTS Sedan AWD V6-3.6L Page 1624
* 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 fan 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.
Note:
* The control circuits for the cooling fan relays are pulled-up to a voltage within the ECM, 2.6-4.6 volts on the control circuit is normal.
* The following test must be performed on all three fan relay control circuit terminals.
3. Connect the red lead of the DMM to a control circuit terminal listed below. Connect the black lead to ground. Set the DMM on the diode
setting. The DMM should display OL.
* KR20C cooling fan low speed relay terminal 86
* KR20D cooling fan high speed relay terminal 86
* KR20E cooling fan speed control relay terminal 85
瀚慖f less than the specified range, test the appropriate relay coil control circuit for a short to ground. If the circuit tests normal, replace the
K20 ECM.
Note: The following tests must be performed on all three fan relay circuits.
4. Command the cooling fan relay ON and OFF with a scan tool. The DMM should transition from OL when commanded OFF to less than 1 V
when commanded ON.
瀚慖f the circuit voltage does not correspond to the specified values, test the control circuit for an open/high resistance or for a short to
voltage. If the circuit tests normal, replace the K20 ECM.
5. If all circuits test normal, test or replace the appropriate KR20 relay.
Component Testing
1. Ignition OFF, disconnect the KR20 cooling fan relay.
2. Test for 70-110 ohm between terminals 85 and 86.
瀚慖f not within the specified range, replace the KR20 cooling fan relay.
3. Measure the resistance between the terminals listed below. The DMM should display OL.
