Lexus NX: PIG Power Supply Voltage (C1552,C1554)

DESCRIPTION

When a problem occurs in the power steering system, the power source relay circuit is shut off to stop the power assist.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

Return-to-normal Condition

C1552

PIG Power Supply Voltage

PIG power source circuit malfunction inside ECU

  • EPS fuse
  • PIG power source circuit
  • ECU wire sub-assembly
  • Power steering ECU assembly

On

After normal confirmation

C1554

Power Supply Relay Failure

Power source relay circuit malfunction

  • EPS fuse
  • PIG power source circuit
  • ECU wire sub-assembly
  • Power steering ECU assembly

On

Power switch on (IG) again

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

If the power steering ECU assembly has been replaced, perform assist map writing.

Click here

HINT:

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

PROCEDURE

1.

CHECK CONNECTOR CONNECTION CONDITION AND GROUND WIRE

(a) Check the connection condition of the ECU wire sub-assembly and power steering ECU assembly connectors.

OK:

The ECU wire sub-assembly and power steering ECU assembly connectors are securely connected.

(b) Check that the ground wire is securely installed with the bolt.

Click here

OK:

The ground wire is securely installed with the bolt.

NG

CONNECT CONNECTOR OR INSTALL GROUND WIRE

OK

2.

READ VALUE USING TECHSTREAM (PIG POWER SUPPLY)

(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 / EMPS / Data List.

(f) Select the item "PIG Power Supply" in the Data List and read the value displayed on the Techstream.

Chassis > EMPS > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

PIG Power Supply

Power source voltage to active motor

Min.: 0.0000 V

Max.: 20.1531 V

Always: 9 to 16 V

-

Chassis > EMPS > Data List

Tester Display

PIG Power Supply

OK:

The normal condition value is displayed on the Techstream.

OK

CHECK INTERMITTENT PROBLEMS

NG

3.

CHECK HARNESS AND CONNECTOR (AUXILIARY BATTERY - ECU WIRE SUB-ASSEMBLY)

(a) Disconnect the An1 ECU wire sub-assembly connector.

*a

Front view of wire harness connector

(to ECU Wire Sub-assembly)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

An1-1 (PIG) - Body ground

Always

9 to 16 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

CHECK ECU WIRE SUB-ASSEMBLY

(a) Connect the An1 connector to the ECU wire sub-assembly.

*a

Front view of wire harness connector

(to Power Steering ECU Assembly)

(b) Disconnect the n1 power steering ECU assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

n1-1 (PIG) - Body ground

Always

9 to 16 V

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

n1-2 (PGND) - Body ground

Always

Below 1 Ω

OK

REPLACE POWER STEERING ECU ASSEMBLY

NG

REPAIR OR REPLACE ECU WIRE SUB-ASSEMBLY

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