Workshop Manuals Factory service & repair Vauxhall
Vauxhall Astra J12 · HVAC
12 · Heating & A/C

Air Conditioning Compressor Malfunction

Make
Vauxhall
Model
Astra J
Section
HVAC Systems - Automatic › Other Information › Air Conditioning Compressor Malfunction
HVACAir Conditioning Compressor Malfunction

Air Conditioning Compressor Malfunction

Diagnostic Instructions

    •  Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    •  Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

A/C Compressor B+

B393B 04

B393B 04

--

--

A/C Compressor Control

B393B 04

B393B 04

B393B 0B

1

1. A/C Compressor Malfunction

Circuit/System Description

The HVAC control module supplies battery voltage to the A/C compressor. When the A/C switch is pressed, the HVAC control module provides a pulse width modulation (PWM) signal to the A/C compressor in order to command the performance of the A/C compressor. The performance of the A/C compressor is regulated according to adjusted interior temperature on the basis of characteristic lines. Therefore the HVAC control module grounds the A/C compressor with the PWM signal.

Diagnostic Aids

The following conditions must be met in order for the HVAC control module to turn on the A/C compressor:

    •  Battery voltage is between 9-18 V.
    •  Engine coolant temperature is less than 124°C (255°F).
    •  Engine speed is greater than 600 RPM.
    •  Engine speed is less than 5 500 RPM.
    •  A/C high side pressure is between 269-2 929 kPa (39-425 PSI).
    •  Throttle position is less than 100%.
    •  Evaporator temperature is greater than 3°C (38°F).
    •  ECM does not detect immoderate torque load
    •  ECM does not detect insufficient idle quality
    •  The ambient temperature is above 1°C (34°F).

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Wiring Repairs


Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

Note:  Before executing Circuit/System Testing, all conditions shown in Diagnostic Aids must be met.

  1. Ignition ON, press and release the A/C switch. Verify the scan tool A/C Switch parameter changes between Active and Inactive.
    2. ⇒ If not the specified value, replace the A26 HVAC Control.
  2. If all circuits test normal, replace the K33 HVAC Control Module and verify the Q46 Air Conditioning Compressor Valve can be activated and deactivated. If the Q46 Air Conditioning Compressor Valve cannot be activated or deactivated, replace the Q46 Air Conditioning Compressor Valve.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Control Module References for HVAC control module replacement, setup, and programming

Parts & tools for this job For Vauxhall Astra

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