Lexus IS250 · Service Manual COMMUNICATION SYSTEM

Power Steering ECU Communication Stop Mode

Circuit diagnosis

DESCRIPTION

Detection Item
 Symptom
 Trouble Area
Power Steering ECU Communication Stop Mode
  1. "EPS" is not displayed on the "Communication Bus Check" screen of the intelligent tester
  2. Applies to "Power Steering ECU Communication Stop Mode" in the "DTC COMBINATION TABLE"
  1. Power source circuit of the power steering ECU
  2. Power steering ECU branch line or connector
  3. Power steering ECU

HINT:
"EPS" refers to the circuit that includes the power steering ECU.


WIRING DIAGRAM

C126151E06

INSPECTION PROCEDURE


1. CHECK CAN BUS LINE FOR OPEN (POWER STEERING ECU BRANCH LINE)

  1. Turn the engine switch off.

  1. Disconnect the power steering ECU connector (A31).

  1. C121570E02
    Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Value
    A31-2 (CANH) - A31-3 (CANL)
    		 Engine switch off
    		 54 to 69 Ω



NG
REPAIR OR REPLACE POWER STEERING ECU BRANCH LINE OR CONNECTOR (CANH, CANL)
OK


2. CHECK WIRE HARNESS (IG, PGND)

  1. C121570E03
    Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Value
    A31-5 (PGND) - Body ground
    		 Always
    		 Below 1 Ω

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

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Value
    A31-9 (IG) - Body ground
    		 Engine switch on (IG)
    		 10 to 14 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE POWER STEERING ECU


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