DTC 4-1: Red LED Error: Procedure

Fig 1: Checking Harness And Connector (Mayday ECU - MAP Light (Mayday Switch))

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the R23 ECU connector.
2. Disconnect the X6 map light connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   R23-4 (IND1) - X6-4 (IND1)	Always	Below 1 Ω
   R23-4 (IND1) or X6-4 (IND1) - Body ground	Always	10 kΩ or higher

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

OK: Go to next step 

1. Temporarily replace the map light with a new or normally functioning one. Refer to REMOVAL .
2. Check that the system operates normally.

   OK

   Red LED operates normally.

NG → REPLACE MAYDAY ECU TOGETHER WITH MAYDAY BATTERY AND THEN PERFORM REGISTRATION 

OK → END (MAP LIGHT (RED LED) IS FAULTY; CLEAR HISTORIC DTC)