HVAC - Automatic
DTC B393B
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC B393B 04
-
Air Conditioning Compressor Valve Control Circuit Open
DTC B393B 0B
-
Air Conditioning Compressor Valve Control Circuit High Current
Diagnostic Fault Information
Circuit/System Description
The HVAC control module supplies 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.
Conditions for Running the DTC
* Ignition ON.
* The HVAC control module is ON.
Conditions for Setting the DTC
B393B 04
A PWM greater than 10% is send out but no current is read back.
B393B 0B
Measured current is above threshold of 815 mA.
Action Taken When the DTC Sets
B393B 04
The A/C compressor is disabled.
B393B 0B
* The A/C compressor is disabled.
* Output will be switched off for hardware protection.
Conditions for Clearing the DTC
The condition for setting the DTC is no longer present.
Reference Information
Schematic Reference
HVAC Schematics HVAC - Automatic
Connector End View Reference
Component Connector End Views Sunshade - Left (DH6)
Description and Operation
Automatic HVAC Description and Operation HVAC - Automatic
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the Q46 Air Conditioning Compressor Valve.
2. Ignition ON, test for greater than 9 V between the control circuit terminal B and ground.
• If less than the specified range, test the control circuit for a short to ground or an open/high resistance.
3. Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module.
4. Ignition ON, test for less than 0.3 V between the control circuit terminal 10 X2 and ground.
• If greater than the specified range, test the control circuit for a short to voltage.
5. Ignition OFF, test for infinite resistance between the control circuit terminal 10 X2 and ground.
• If less than the specified range, test the control circuit for a short to ground.
6. Test for less than 5 ohms between the Q46 Air Conditioning Compressor Valve control circuit terminal A and control circuit terminal 10 X2 at the K33 HVAC Control Module harness connector
• If greater than the specified value, test the control circuit for an open/high resistance.
7. If all circuits test normal, test or replace the Q46 Air Conditioning Compressor Valve and verify the DTC does not reset.
• If the DTC resets, replace the K33 HVAC Control Module.
Component Testing
Static Test
1. Ignition OFF, disconnect the harness connector at the Q46 Air Conditioning Compressor Valve.
2. Test for 7-15 ohms between B+ circuit terminal A and control circuit terminal B.
• If not within the specified range, replace the Q46 Air Conditioning Compressor Valve.
3. Test for infinite resistance between each terminal and the Q46 Air Conditioning Compressor Valve housing/case.
• If not the specified value, replace the Q46 Air Conditioning Compressor Valve.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Air Conditioning Compressor Replacement (LE9) Air Conditioning Compressor Replacement (LE9)Air Conditioning Compressor Replacement (V6) Air Conditioning Compressor Replacement (V6)
* Control Module References Control Module References for HVAC control module replacement, setup, and programming