Mazda Factory OBD-II DTC U0073, U0516, U1900, U2516, 16:ER12 Code Diagnostic Procedure

Mazda	U0073	SAS control module
	U0516	Climate control unit
	U1900	PJB Water heater unit
	U2516	Instrument cluster
	16:Er12	Audio unit
DETECTION CONDITION		Warning • Detection conditions are for understanding the DTC outline before performing an inspection. Performing an inspection according to only detection conditions may cause injury due to operating error, or damage the system. When performing an inspection, always follow the inspection procedure. • CAN system related harness malfunction • Related module communication error
POSSIBLE CAUSE		• Open or short circuit in wiring harness • Malfunction of connectors between SAS control module, climate control unit, audio unit (base module), information display, water heater unit, PJB and instrument cluster • SAS control module malfunction • Climate control unit malfunction • Audio unit (base module) malfunction • Information display malfunction • Water heater unit malfunction • PJB malfunction • Instrument cluster malfunction

Diagnostic procedure

STEP	INSPECTION		ACTION
1	INSPECT CAN SYSTEM-RELATED DTC • Are any DTCs other than the following displayed? ― U0073 ― U0516 ― U1900 ― U2516 ― 16:Er12	Yes	Determine malfunctioning part in CAN system.
1		No	Go to the next step.
2	INSPECT CONNECTOR • Inspect the connector of the module that outputs the DTC. • Is it normal?	Yes	Go to the next step.
2		No	Repair or replace the connector, then go to Step 4.
3	INSPECT WIRING HARNESSES • Inspect for the following malfunctioning wiring harnesses: ― Short to GND ― Short to power supply ― Twisted pair short each other ― Open circuit • Is there any malfunction?	Yes	Repair or replace the wiring harness, then go to the next step.
3		No	Go to the next step.
4	VERIFY TROUBLESHOOTING COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC using the M-MDS. • Is the same DTC present?	Yes	Replace the module that outputs the DTC, then retry this step.
4		No	Troubleshooting completed.