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. |
DTC Descriptor
DTC B393B 04: Air Conditioning Compressor Valve Control Circuit Open circuitDTC B393B 0B: Air Conditioning Compressor Valve Control Circuit Current Above Threshold
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.
Conditions for Running the DTC
| • | Ignition ON. |
| • | The HVAC control module is ON. |
Conditions for Setting the DTC
P393B 04
Measured current is above threshold of 815 mA.
P393B 0B
A PWM greater than 10% is send out but no current is read back.
Action Taken When the DTC Sets
P393B 04
The A/C compressor is disabled.
P393B 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
Connector End View Reference
Description and Operation
Manual HVAC Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the Q46 Air Conditioning Compressor Valve.
- Ignition ON, test for greater than 11 V between the B+ circuit terminal B and ground.
- Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module.
- Ignition ON, test for less than 0.3 V between the control circuit terminal 10 (X2) and ground.
- Ignition OFF, test for infinite resistance between the control circuit terminal 10 (X2) and ground.
- Test for less than 5 Ω 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 all circuits test normal, test or replace the Q46 Air Conditioning Compressor Valve and verify the DTC does not reset.
| ⇒ | If less than the specified range, test the B+ circuit for a short to ground or an open/high resistance. |
| ⇒ | If greater than the specified range, test the control circuit for a short to voltage. |
| ⇒ | If less than the specified range, test the control circuit for a short to ground. |
| ⇒ | If greater than the specified value, test the control circuit for an open/high resistance. |
| ⇒ | If the DTC resets, replace the K33 HVAC Control Module. |
Component Testing
Static Test
- Ignition OFF, disconnect the harness connector at the Q46 Air Conditioning Compressor Valve.
- Test for 7-10 Ω between control circuit terminal A and B+ circuit terminal B.
- Test for infinite resistance between each terminal and the Q46 Air Conditioning Compressor Valve housing/case.
| ⇒ | If not within the specified range, replace the Q46 Air Conditioning Compressor Valve. |
| ⇒ | If not the specified value, replace the Q46 Air Conditioning Compressor Valve. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
