Inspection Procedure

1. Disconnect the R23 ECU connector.
Fig 1: Identifying R23 ECU And X4 Map Light Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the X4 map light connector.
3. Measure the resistance according to the value (s) in the table below.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION REFERENCE CHART
   
   

   Tester Connection	Condition	Specified Condition
   R23-5 (SIG1) - X4-30 (SIG1)	Always	Below 1 Ω
   R23-12 (SIG-) - X4-32 (GND3)	Always	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR THEN CLEAR HISTORIC DTC 

OK: Go to Next Step 

1. Remove the map light for standard body (see REMOVAL ) or long body (see REMOVAL ).
2. Measure the resistance according to the value (s) in the table below.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION REFERENCE CHART
   
   

   Tester Connection	Condition	Specified Condition
   30 (SIG1) - 32 (GND3)	EMERGENCY button is pressed	305 to 313 Ω
   30 (SIG1) - 32 (GND3)	VOL+ button is pressed	812 to 831 Ω
   30 (SIG1) - 32 (GND3)	VOL- button is pressed	1811 to 1848 Ω

   Fig 2: Identifying Map Light Assembly Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE MAP LIGHT ASSEMBLY (MAYDAY SWITCH) THEN CLEAR HISTORIC DTC 

OK: REPLACE MAYDAY ECU TOGETHER WITH MAYDAY BATTERY AND THEN PERFORM REGISTRATION