Lexus NX: A/C Inverter High Voltage Power Resource System Malfunction (B1471)
DESCRIPTION
The hybrid vehicle control ECU monitors the voltage of the HV battery. The hybrid vehicle control ECU stops compressor control and stores this DTC when the monitored voltage is outside the specified range.
This DTC will be stored as a history DTC. Compressor control may not resume unless the power switch is turned off.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Memory | Note |
|---|---|---|---|---|---|
| B1471 | A/C Inverter High Voltage Power Resource System Malfunction |
|
| Memorized | - |
WIRING DIAGRAM
CAUTION / NOTICE / HINT
CAUTION:
- Wear insulated gloves and pull out the service plug grip before inspection as procedures may require disconnecting high-voltage connectors. Carry the removed service plug in your pocket to prevent other technicians from accidentally reconnecting it while you are servicing the vehicle.
- Do not touch the high-voltage connectors or terminals for 10 minutes after the service plug grip is removed.
NOTICE:
- Inspect the fuses for circuits related to this system before performing the following procedure.
-
After the power switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.
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-
When disconnecting and reconnecting the auxiliary battery terminal
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HINT:
When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.
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- The hybrid control system and air conditioning system output DTCs separately. Perform troubleshooting for the hybrid control system first if DTCs from these systems are output simultaneously.
PROCEDURE
| 1. | CHECK CAN COMMUNICATION SYSTEM |
(a) Using the Techstream, check if the CAN communication system is functioning normally.
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| Result | Proceed to |
|---|---|
| CAN communication system DTCs are not output | A |
| CAN communication system DTCs are output | B |
| B | .gif) | GO TO CAN COMMUNICATION SYSTEM |
|
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| 2. | CHECK FOR DTC (HYBRID CONTROL SYSTEM) |
(a) Check if hybrid control system DTCs are output.
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OK:
Hybrid control system DTCs are not output.
| NG | | GO TO HYBRID CONTROL SYSTEM |
|
| 3. | INSPECT HIGH VOLTAGE FUSE |
CAUTION:
Be sure to wear insulated gloves.
(a) Turn the power switch off.
(b) Remove the service plug grip.
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CAUTION:
Do not touch the high-voltage connectors or terminals for 10 minutes after the service plug grip is removed.
NOTICE:
After removing the service plug grip, turning the power switch on (READY) may cause a malfunction. Do not turn the power switch on (READY) with the service plug grip removed.
(c) Remove the connector cover assembly.
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NOTICE:
Be sure to prevent foreign matter or water from entering the inverter with converter assembly.
| (d) Check that bolts A and B are tightened securely. |
|
(e) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Item (Tester Connection) | Condition | Specified Condition |
|---|---|---|
| High voltage fuse (A - B) | Always | Below 1 Ω |
| NG | | REPLACE HIGH VOLTAGE FUSE |
|
| 4. | INSPECT ENGINE WIRE |
CAUTION:
Be sure to wear insulated gloves.
(a) Disconnect the C47 and C46 engine wire connectors.
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NOTICE:
Do not allow any foreign matter or water to enter the compressor with motor assembly.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| C46-1 (PE) - C47-1 (ACPE) | Always | Below 1 Ω |
| C46-2 (PB) - C47-2 (ACPB) | Always | Below 1 Ω |
| C46-1 (PE) or C47-1 (ACPE) - Body ground | Always | 10 kΩ or higher |
| C46-2 (PB) or C47-2 (ACPB) - Body ground | Always | 10 kΩ or higher |
| OK | | REPLACE COMPRESSOR WITH MOTOR ASSEMBLY |
| NG | | REPLACE ENGINE WIRE |
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C
SEE MORE:
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Dtc Check / Clear
DTC CHECK / CLEAR NOTICE: When using the Techstream with the power switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manu
