DTC C1020-00: Ignition Switch On/Start Position Malfunction [12/2023 - ]: Procedure

• Make sure that there is no looseness at the locking part and the connecting part of the connector.

  OK

  The connector is securely connected.

Pre-procedure1

• Disconnect the A5 No. 1 skid control ECU (brake booster with master cylinder assembly) connector.

• Check both the connector case and the terminals for deformation and corrosion.

  OK

  No deformation or corrosion.

Pre-procedure2

• Turn the ignition switch to ON.

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

  Standard Voltage

  Tester Connection	Switch Condition	Specified Condition	Result
  A5-31 (IG1) - Body ground	Ignition switch ON	11 to 14 V	V

  Result

  Proceed to
  OK
  NG

Post-procedure1

• None

Result: 

OK 

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [12/2023 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR