2010 Cadillac CTS Sedan AWD V6-3.6L Page 1561
瀚慖f the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
瀚慖f the test lamp is always OFF, test the control circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace
the ECM.
11. If all circuits test normal, test or replace the A/C clutch relay.
Component Testing
1. Ignition OFF, disconnect the A/C COMP relay.
2. Test for 60-180 ohms between terminals 85 and 86.
瀚慖f the resistance is not within the specified range, replace the relay.
3. Test for infinite resistance between the following terminals:
* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87
瀚慖f not the specified value, replace the relay.
4. Install a 30-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test
for less than 2 ohms between terminals 30 and 87.
瀚慖f greater than the specified range, replace the relay.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Air Conditioning Compressor Replacement (LF1, LLT) (See: Heating and Air Conditioning/Compressor HVAC/Service and
Repair/Removal and Replacement)Air Conditioning Compressor Replacement (LSA) (See: Heating and Air Conditioning/Compressor
HVAC/Service and Repair/Removal and Replacement)
* Relay Replacement (Attached to Wire Harness) (See: Power and Ground Distribution/Power Distribution Relay/Service and Repair/Relay
Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (See: Power and Ground Distribution/Power
Distribution Relay/Service and Repair/Relay Replacement (Within an Electrical Center))
* Control Module References (See: Testing and Inspection/Programming and Relearning) for HVAC control module and ECM replacement,
setup, and programming
P0650
DTC P0650
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0650
- Malfunction Indicator Lamp (MIL) Control Circuit
Diagnostic Fault Information
Circuit/System Description
