Determination procedure

WARNING: This page is about a different car, the 2017 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION:

When disconnecting the connector, verify that there is no looseness, damage, deformation, corrosion, or poor connection of the connector terminals.
When inspecting the DLC-2, touch it with a paper clip or similar thin pin without directly inserting a tester into the terminals.
Disconnect the negative battery cable before performing any work that requires handling of connectors.

Step	Inspection		Action
1	INSPECT FOR SHORT TO POWER SUPPLY BETWEEN CONNECTOR C-34 AND INSTRUMENT CLUSTER Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Disconnect connector C-34. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Switch the ignition ON (engine off). Measure the voltage at instrument cluster terminals C and E. Is the voltage between 1.5 - 3.5 V?	Yes	Go to Step 3.
1		No	Go to the next step.
2	INSPECT INSTRUMENT CLUSTER FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Disconnect the instrument cluster connector. Connect connector C-34. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Switch the ignition ON (engine off). Measure the voltage at DLC-2 terminals L and K. Is the voltage between 1.5 - 3.5 V?	Yes	Replace the instrument cluster because there is a short to the power supply in the instrument cluster. (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION .)
2		No	Repair or replace the wiring harness between the instrument cluster and connector C-34 because the wiring harness is shorted to the power supply.
3	INSPECT JB No. 2 FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Connect the instrument cluster connector. Connect connector C-34. Disconnect connector C-33. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Switch the ignition ON (engine off). Measure the voltage at instrument cluster terminals C and E. Is the voltage between 1.5 - 3.5 V?	Yes	Go to the next step.
3		No	Replace the JB No. 2 because there is a short to the power supply in the JB No. 2.
4	INSPECT FOR SHORT TO POWER SUPPLY BETWEEN CONNECTOR C-33 AND DLC-2 Measure the voltage at DLC-2 terminals L and K. Is the voltage 0 V?	Yes	Go to the next step.
4		No	Repair or replace the wiring harness between the DLC-2 and connector C-33 because the wiring harness is shorted to the power supply.
5	INSPECT FOR SHORT TO POWER SUPPLY BETWEEN CONNECTOR C-33 AND CLIMATE CONTROL UNIT Measure the voltage at climate control unit terminals 1S and 1U (with full-auto a/c (dual type)). Measure the voltage at climate control unit terminals D and B (with full-auto a/c (single type)). Is the voltage between 1.5 - 3.5 V?	Yes	Go to Step 7.
5		No	Go to the next step.
6	INSPECT CLIMATE CONTROL UNIT FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Disconnect the climate control unit connector. Connect connector C-33. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Switch the ignition ON (engine off). Measure the voltage at DLC-2 terminals L and K. Is the voltage between 1.5 - 3.5 V?	Yes	Replace the climate control unit because there is a short to the power supply in the climate control unit. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] .)
6		No	Repair or replace the wiring harness between the climate control unit and connector C-33 because the wiring harness is shorted to the power supply.
7	INSPECT FOR SHORT TO POWER SUPPLY BETWEEN CONNECTOR C-33 AND CONNECTOR C-59 Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Connect connector C-33. Disconnect the connector C-59. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Switch the ignition ON (engine off). Measure the voltage at DLC-2 terminals L and K. Is the voltage between 1.5 - 3.5 V?	Yes	Go to the next step.
7		No	Repair or replace the wiring harness between connector C-33 and connector C-59 because the wiring harness is shorted to the power supply.
8	INSPECT FOR SHORT TO POWER SUPPLY BETWEEN BLIND SPOT MONITORING (BSM) CONTROL MODULE (LH) AND REAR BODY CONTROL MODULE (RBCM) Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Disconnect the rear body control module (RBCM) connector. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Switch the ignition ON (engine off). Measure the voltage at blind spot monitoring (BSM) control module (LH) terminals C and D. Is the voltage between 1.5 - 3.5 V?	Yes	Go to Step 11.
8		No	Go to the next step.
9	INSPECT FOR SHORT TO POWER SUPPLY BETWEEN BLIND SPOT MONITORING (BSM) CONTROL MODULE (LH) AND CONNECTOR C-19 Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Disconnect connector C-19. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Switch the ignition ON (engine off). Measure the voltage at blind spot monitoring (BSM) control module (LH) terminals C and D. Is the voltage between 1.5 - 3.5 V?	Yes	Repair or replace the wiring harness between the rear body control module (RBCM) and connector C-19 because the wiring harness is shorted to the power supply.
9		No	Go to the next step.
10	INSPECT BLIND SPOT MONITORING (BSM) CONTROL MODULE (LH) FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Disconnect the blind spot monitoring (BSM) control module (LH) connector. Connect connector C-19. Connect the rear body control module (RBCM) connector. Connect connector C-59. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Switch the ignition ON (engine off). Measure the voltage at DLC-2 terminals L and K. Is the voltage between 1.5 - 3.5 V?	Yes	Replace the blind spot monitoring (BSM) control module (LH) because there is a short to power supply in the blind spot monitoring (BSM) control module (LH). (See BLIND SPOT MONITORING (BSM) CONTROL MODULE REMOVAL/INSTALLATION .)
10		No	Repair or replace the wiring harness between the blind spot monitoring (BSM) control module (LH) and connector C-19 because the wiring harness is shorted to the power supply.
11	INSPECT REAR BODY CONTROL MODULE (RBCM) FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Connect connector C-59. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Switch the ignition ON (engine off). Measure the voltage at DLC-2 terminals L and K. Is the voltage between 1.5 - 3.5 V?	Yes	Replace the rear body control module (RBCM) because there is a short to the power supply in the rear body control module (RBCM). (See REAR BODY CONTROL MODULE (RBCM) REMOVAL/INSTALLATION .)
11		No	Repair or replace the wiring harness between the rear body control module (RBCM) and connector C-59 because the wiring harness is shorted to the power supply.