DTC U0131-433: Lost Communication with Power Steering Control Module; DTC U0131-434: Lost Communication with Power Steering Control Module: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch ON (IG).
3. Clear the DTC.
4. Check for DTC.

   HINT: 

   When DTCs other than U0131 are output, inspect and repair the trouble areas indicated by those DTCs first.

   RESULT
   
   

   Result	Proceed to
   DTC U0131 is not output	A
   DTC U0131 is output	B

B → GO TO ELECTRONIC POWER STEERING SYSTEM 

A: Go to next step 

1. Disconnect the A23 power steering ECU connector.
   Fig 1: Identifying A23 Power Steering ECU Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance of the wire harness side connector.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   A23-2 (CANH) - A23-3 (CANL)	Power switch OFF	54 to 69 Ω

NG → REPAIR OR REPLACE POWER STEERING ECU BRANCH WIRE OR CONNECTOR (CANH, CANL) 

OK: Go to next step 

1. Disconnect the A23 power steering ECU connector.
   Fig 2: Identifying A23 Power Steering ECU Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance of the wire harness side connector.

   Standard resistance

   Tester Connection	Specified Condition
   A23-5 (PGND) - Body ground	Below 1 Ω

3. Measure the voltage of the wire harness side connector.

   Standard voltage

   Tester Connection	Condition	Specified Condition
   A23-9 (IG) - Body ground	Power switch ON (IG)	10 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → REPLACE POWER STEERING ECU