Diagnostic Procedure

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.

DTC B1B87:2A [DASH-ELECTRICAL SUPPLY UNIT] DIAGNOSTIC PROCEDURE

Step	Inspection	Results	Action
1	INSPECT POSITION MEMORY CONTROL MODULE CONNECTOR FOR MALFUNCTION Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION .) Are the connector and terminal normal?	Yes	Go to the next step.
1		No	Repair or replace the malfunctioning location and perform the repair completion verification.
2	INSPECT LIFT POSITION SENSOR POWER SUPPLY CIRCUIT AND SIGNAL CIRCUIT FOR SHORT TO GROUND Verify that the position memory control module connector is disconnected. Inspect for continuity between the following terminals (wiring harness-side) and body ground: Position memory control module terminal 2J Position memory control module terminal 2N Is there continuity?	Yes	Repair or replace the malfunctioning location and perform the repair completion verification. (See FRONT SEAT REMOVAL/INSTALLATION (US) .)
2		No	Go to the next step.
3	INSPECT LIFT POSITION SENSOR POWER SUPPLY CIRCUIT AND SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY Verify that the position memory control module connector is disconnected. Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off or on). Measure the voltage at the following terminals (wiring harness-side): Position memory control module terminal 2J Position memory control module terminal 2N Is the voltage 0 V?	Yes	Go to the next step.
3		No	Repair or replace the malfunctioning location, then go to the next step. (See FRONT SEAT REMOVAL/INSTALLATION (US) .)
4	INSPECT POSITION MEMORY CONTROL MODULE FOR MALFUNCTION DEPENDING ON REPEATABILITY Install/connect the part removed/disconnected during the troubleshooting procedure. Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the dash-electrical supply unit. (See DTC INSPECTION .) Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW (US) .) If the CAN communication is normal, replace the malfunctioning location and go to the next step. (See POSITION MEMORY CONTROL MODULE REMOVAL/INSTALLATION (US) .)
4		No	Go to repair completion verification 2.
5	INSPECT LIFT POSITION SENSOR AND LIFT POSITION SENSOR CIRCUIT FOR MALFUNCTION DEPENDING ON REPEATABILITY Install/connect the part removed/disconnected during the troubleshooting procedure. Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the dash-electrical supply unit. (See DTC INSPECTION .) Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW (US) .) If the CAN communication is normal, replace the malfunctioning location and perform the repair completion verification. (See FRONT SEAT REMOVAL/INSTALLATION (US) .)
5		No	Go to repair completion verification 2.
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED Install/connect the part removed/disconnected during the troubleshooting procedure. Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the dash-electrical supply unit. (See DTC INSPECTION .) Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW (US) .) If the CAN communication is normal, perform the diagnosis from Step 1. If the malfunction recurs, replace the dash-electrical supply unit, then go to the next step. (See DASH-ELECTRICAL SUPPLY UNIT REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER (US)] .) (See DASH-ELECTRICAL SUPPLY UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER (US)] .)
Repair completion verification 1		No	Go to the next step.
Repair completion verification 2	VERIFY IF OTHER DTCs DISPLAYED Perform the DTC inspection. (See DTC INSPECTION .) Are any DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
Repair completion verification 2		No	DTC troubleshooting completed.