DTC U0198: Lost Communication with Telematic Control Module: Procedure

CHECK HARNESS AND CONNECTOR (COMMUNICATION LINE)

Disconnect the R24 and L93 ECU connectors.

Fig 1: Identifying R24 And L93 ECU Connector Terminals
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Measure the resistance according to the value(s) in the table below.

Standard resistance

Tester Connection	Condition	Specified Condition
R24-23 (MPX1) - L93-5 (S1)	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step

CHECK HARNESS AND CONNECTOR (MAYDAY ECU - VEHICLE BATTERY AND BODY GROUND)

Disconnect the R24 ECU connector.

Fig 2: Identifying R24 ECU Connector
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Measure the voltage and resistance according to the value(s) in the table below.

Standard voltage

Standard resistance

Tester Connection	Condition	Specified Condition
R24-1 (+B) - Body ground	Always	11 to 14 V

Tester Connection	Condition	Specified Condition
R24-12 (E) - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

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