Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.

CHECK HARNESS AND CONNECTOR (MAYDAY ECU - MAP LIGHT (MAYDAY SWITCH))

Disconnect the R23 ECU connector
Disconnect the X4 map light connector.
Measure the resistance according to the value(s) in the table below

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
R23-13 (SIG2) - X4-31 (SIG2)	Always	Below 1 Ω
R23-12 (SIG-) - X4-32 (GND3)	Always	Below 1 Ω

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

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

OK: Go to next step

INSPECT MAP LIGHT ASSEMBLY (MAYDAY SWITCH)

Remove the map light (see REMOVAL )
Measure the resistance according to the value(s) in the table below.

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
31 (SIG2) - 32 (GND3)	SERVICES button is pressed	305 to 313 Ω
31 (SIG2) - 32 (GND3)	PHONE button is pressed	812 to 831 Ω
31 (SIG2) - 32 (GND3)	PTT button is pressed	1811 to 1848 Ω

Fig 2: Inspecting MAP Light Assembly (Mayday Switch)

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

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