Lexus NX: Power Source Voltage Malfunction (C1782)

DESCRIPTION

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

C1782

Power Source Voltage Malfunction

While the power switch is on (IG), the voltage at terminal B is 10 V or less, or 16 V or higher for 0.5 seconds.

  • AVS fuse
  • Auxiliary battery
  • Charging system
  • Harness or connector
  • Absorber control ECU

Does not come on

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Before performing troubleshooting, inspect the connectors of related circuits.
  • Before replacing the absorber control ECU, perform all of the following again: 1) symptom simulation ; 2) DTC inspection ; and 3) Techstream inspection (ECU Data List or Active Test ). If no malfunctions are found in other areas, replace the absorber control ECU.
  • When the absorber control ECU is replaced, switch to test mode and check that all test mode DTCs are cleared when their respective deletion conditions are met.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.

READ VALUE USING TECHSTREAM (IG POWER SOURCE VOLTAGE)

(a) Turn the power switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the power switch on (IG).

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / Air suspension / Data List.

Chassis > Air suspension > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

IG Power Source Voltage

ECU power supply voltage

Min.: 0.0 V

Max.: 25.5 V

11 to 14 V (Actual ECU power supply voltage): Power switch on (IG)

-

Chassis > Air suspension > Data List

Tester Display

IG Power Source Voltage

OK:

The normal condition value is displayed on the Techstream.

NG

GO TO STEP 3

OK

2.

CHECK FOR DTC

(a) Clear the DTCs.

Click here

Chassis > Air suspension > Clear DTCs

(b) Turn the power switch off.

(c) Check for DTCs.

Click here

Chassis > Air suspension > Trouble Codes

Result

Proceed to

DTC is not output

A

DTC is output

B

A

USE SIMULATION METHOD TO CHECK

B

REPLACE ABSORBER CONTROL ECU

3.

INSPECT AUXILIARY BATTERY

(a) Check the auxiliary battery voltage.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

Auxiliary battery

Power switch on (IG)

11 to 14 V

Auxiliary battery

Power switch on (READY)

11 to 15.5 V

NG

CHECK OR REPLACE CHARGING SYSTEM OR BATTERY

OK

4.

CHECK TERMINAL VOLTAGE (IGB)

(a) Turn the power switch off.

(b) Disconnect the Q22 absorber control ECU connector.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

Q22-1 (IGB) - Body ground

Power switch on (IG)

11 to 14 V

*a

Front view of wire harness connector

(to Absorber Control ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

5.

CHECK HARNESS AND CONNECTOR (GND TERMINAL)

(a) Turn the power switch off.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

Q22-4 (GND) - Body ground

Always

Below 1 Ω

*a

Front view of wire harness connector

(to Absorber Control ECU)

OK

REPLACE ABSORBER CONTROL ECU

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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