Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus IS F. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If the certification ECU (smart key ECU assembly) is replaced, register the key (See REGISTRATION ).

CHECK DTC OUTPUT
1. Clear the DTCs (See DTC CHECK / CLEAR )
2. Recheck for DTCs
  OK: B2784 output does not recur.
NG: Go to step 2

OK: USE SIMULATION METHOD TO CHECK (See HOW TO PROCEED WITH TROUBLESHOOTING )

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - ENGINE SWITCH)

Disconnect the certification ECU (smart key ECU assembly) and engine switch connectors

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

Standard Resistance

RESISTANCE REFERENCE

Tester Connection	Condition	Specified Condition
P33-9 (CODE) - J31-10 (CODE)	Always	Below 1 Ω
P33-8 (TXCT) - J31-9 (TXCT)	Always	Below 1 Ω
P33-9 (CODE) - Body ground	Always	10 kΩ or higher
P33-8 (TXCT) - Body ground	Always	10 kΩ or higher

Fig 1: Identifying P33 And J31 Connector Terminal

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next Step

REPLACE ENGINE SWITCH
1. Replace the engine switch (See REMOVAL )
CHECK DTC OUTPUT
1. Clear the DTCs (See DTC CHECK / CLEAR )
2. Recheck for DTCs
  OK: B2784 output does not recur.
NG: REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (See REMOVAL )

OK: END (ENGINE SWITCH IS DEFECTIVE)