DTC B393B
DTC B393B |
Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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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 | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
A/C Compressor B+
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B393B 04
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B393B 04
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-
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-
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A/C Compressor Control
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B393B 04
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B393B 04
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B393B 0B
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1
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1. A/C Compressor Malfunction
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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 |
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Ignition ON.
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The HVAC control module is ON.
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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
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The A/C compressor is disabled.
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Output will be switched off for hardware protection.
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Conditions for Clearing the DTC |
The condition for setting the DTC is no longer present.
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
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing |
1. |
Ignition OFF, disconnect the harness connector at the Q46 Air Conditioning Compressor Valve.
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2. |
Ignition ON, test for greater than 11 V between the B+ circuit terminal B and ground.
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3. |
If less than the specified range, test the B+ circuit for a short to ground or an open/high resistance.
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4. |
Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module.
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5. |
Ignition ON, test for less than 0.3 V between the control circuit terminal 10 X2 and ground.
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6. |
If greater than the specified range, test the control circuit for a short to voltage.
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7. |
Ignition OFF, test for infinite resistance between the control circuit terminal 10 X2 and ground.
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8. |
If less than the specified range, test the control circuit for a short to ground.
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9. |
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
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10. |
If greater than the specified value, test the control circuit for an open/high resistance.
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11. |
If all circuits test normal, test or replace the Q46 Air Conditioning Compressor Valve and verify the DTC does not reset.
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12. |
If the DTC resets, replace the K33 HVAC Control Module.
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Component Testing |
Static Test
1. |
Ignition OFF, disconnect the harness connector at the Q46 Air Conditioning Compressor Valve.
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2. |
Test for 7-15 Ω between control circuit terminal A and B+ circuit terminal B.
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3. |
If not within the specified range, replace the Q46 Air Conditioning Compressor Valve.
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4. |
Test for infinite resistance between each terminal and the Q46 Air Conditioning Compressor Valve housing/case.
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5. |
If not the specified value, replace the Q46 Air Conditioning Compressor Valve.
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Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Air Conditioning Compressor Replacement (LDK/A20NHT)
Air Conditioning Compressor Replacement (LBS/A20DTH)
Air Conditioning Compressor Replacement (LAU/A28NER)
.
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Control Module References
for HVAC control module replacement, setup, and programming
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