Inspection Procedure

1. Disconnect the M15 ECU connector.
2. Disconnect the O4 map light plate connector.
3. Measure the resistance of the wire harness side connectors.

   Standard resistance 

   RESISTANCE SPECIFICATIONS
   
   

   Tester Connection	Specified Condition
   M15-5 (SIG1) - O4-13 (SIG1)	Below 1 Ω
   M15-12 (SIG-)- O4-9 (SIG-)	Below 1 Ω
   M15-5 (SIG1) or O4-13 (SIG1) - Body ground	10 kΩ or higher
   M15-12 (SIG-) or O4-9 (SIG-) - Body ground	10 kΩ or higher

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

Fig 1: Identifying M15 ECU Connector And O4 Map Light Plate Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step 

1. Remove the map light plate assembly.
2. Remove the mayday switch assembly from the map light plate assembly.
3. Measure the resistance of the switch when each switch is pressed.

   Standard resistance 

   RESISTANCE SPECIFICATIONS
   
   

   Tester Connection	Switch Condition	Specified Condition
   6 (SIG1) - 2 (SIG-)	EMERGENCY	305 to 313 Ω
   6 (SIG1) - 2 (SIG-)	VOL+	812 to 831 Ω
   6 (SIG1) - 2 (SIG-)	VOL-	1811 to 1848 Ω

NG: REPLACE MAYDAY SWITCH ASSEMBLY THEN CLEAR HISTORIC DTC 

Fig 2: Identifying Mayday Switch Assembly Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step 

1. Install the mayday switch assembly to the map light plate assembly.
2. Measure the resistance of the switch when each switch is pressed.

   Standard resistance 

   RESISTANCE SPECIFICATIONS
   
   

   Tester Connection	Switch Condition	Specified Condition
   13 (SIG1) - 9 (SIG-)	EMERGENCY	305 to 313 Ω
   13 (SIG1) - 9 (SIG-)	VOL+	812 to 831 Ω
   13 (SIG1) - 9 (SIG-)	VOL-	1811 to 1848 Ω

NG: REPLACE MAP LIGHT PLATE ASSEMBLY THEN CLEAR HISTORIC DTC 

Fig 3: Identifying Map Light Plate Assembly Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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