April 5, 2026: LEMON Manuals is launched! Read the announcement.

Inspection Procedure

CHECK WIRE HARNESS (ECU - MAP LIGHT PLATE ASSEMBLY (MAYDAY SWITCH ASSEMBLY))

Disconnect the M15 ECU connector.
Disconnect the O4 map light plate connector.

Measure the resistance of the wire harness side connectors.

Standard resistance

RESISTANCE SPECIFICATIONS

Tester Connection	Specified Condition
M15-11 (IND2) - O4-12 (IND2)	Below 1 Ω
M15-11 (IND2) or O4-12 (IND2) - Body ground	10 kΩ or higher

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

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

G05284044

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step

CHECK OPERATION OF MAYDAY SWITCH ASSEMBLY (GREEN LED)
1. Temporarily replace the mayday switch assembly with a new or normally functioning one.
2. Check that the system operates normally.
  OK:
  
  Green LED operates normally.
OK: END (MAYDAY SWITCH ASSEMBLY (GREEN LED) IS FAULTY; CLEAR HISTORIC DTC)

NG: Go to next step
CHECK OPERATION OF MAP LIGHT PLATE ASSEMBLY
1. Temporarily replace the map light plate assembly with a new or normally functioning one.
2. Check that the system operates normally.
  OK:
  
  Green LED operates normally.
NG: REPLACE MAYDAY ECU ASSEMBLY TOGETHER WITH MAYDAY BATTERY AND THEN PERFORM REGISTRATION

OK: END (MAP LIGHT PLATE ASSEMBLY IS FAULTY; CLEAR HISTORIC DTC)