HOLDEN GEN III V8, Service Training

Page: 77 / 113

GEN III V8 ENGINE MANAGEMENT
A failure in the A/C Clutch Circuit will set one of the following DTCs:
DTC P1539 A/C Clutch Status Circuit High Voltage
The PCM activates the A/C clutch relay when the PCM detects an A/C request Voltage is present at both the
A/C compressor clutch and the A/C clutch status terminal at the PCM when the relay is activated A DTC P1539
sets if the PCM detects voltage on the A/C clutch status terminal when the system has not requested the A/C A
short to voltage at any point in the A/C status circuit, or the A/C relay contacts are stuck, sets a DTC P1539
Conditions for running DTC P1539
• The A/C clutch is not requested
Conditions for setting DTC P1539
• Voltage is detected on the A/C status circuit for more than 1 5 seconds after the PCM has disengaged the
A/C clutch relay
Action taken when DTC P1539 Sets
• The PCM stores the DTC information into memory when the diagnostic runs and fails
• The Check Powertrain Lamp will not be illuminated
• The PCM records the operating conditions at the time the diagnostic fails The PCM stores this information
in the Freeze Frame/Failure Records
Conditions for clearing the Check Powertrain Lamp and DTC P1539
• A last test failed (Current DTC) will clear when the diagnostic runs and does not fail
DTC P1546 A/C Clutch Status Circuit Low Voltage
The PCM will activate the A/C clutch relay when the PCM detects that A/C has been requested When the PCM
activates the relay, voltage should be present at both the A/C compressor clutch and the A/C clutch status
circuit at the PCM, if voltage is not present DTC P1546 will set
DTC P1546 Sensor Circuit
Conditions for running DTC P1546
• The A/C clutch is requested
Conditions for setting DTC P1546
• The PCM commands the A/C ON and the PCM does not detect a voltage on the A/C clutch status line for
more than five seconds
Action taken when DTC P1546 Sets
• The PCM stores the DTC information into memory when the diagnostic runs and fails
• The Check Powertrain Lamp will not be illuminated
• The PCM records the operating conditions at the time the diagnostic fails The PCM stores this information
in the Freeze Frame/Failure Records
Conditions for clearing the Check Powertrain Lamp and DTC P1546
• A last test failed (Current DTC) will clear when the diagnostic runs and does not fail
Page - 72 GEN III V8 ENGINE MANAGEMENT