Determination 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.

CAUTION:

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

DETERMINING SHORT TO POWER SUPPLY LOCATION (CAN-BUS No. 4, US) - DIAGNOSTIC PROCEDURE

Step	Inspection		Action
1	INSPECT CAN LINE BETWEEN BODY CONTROL MODULE (BCM) AND CONNECTOR C-08 FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Disconnect the connector C-08. Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off). Measure the voltage at body control module (BCM) terminals 2D and 2B. Is the voltage between 1.5-3.5 V?	Yes	Go to Step 3.
1		No	Go to the next step.
2	INSPECT BODY CONTROL MODULE (BCM) FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Disconnect the connector 2 which has body control module (BCM) terminals 2D and 2B. Connect the connector C-08. Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off). Measure the voltage at body control module (BCM) terminals 2D and 2B (wiring harness side). Is the voltage between 1.5-3.5 V?	Yes	Replace the body control module (BCM) because there is a short to the power supply in the body control module (BCM). (See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION (US) .)
2		No	Repair or replace the wiring harness between the body control module (BCM) and connector C-08 because the wiring harness is shorted to the power supply.
3	INSPECT CAN LINE BETWEEN CONNECTOR C-08 AND CONNECTOR C-69 FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Connect the connector C-08. Disconnect the connector C-69. Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off). Measure the voltage at body control module (BCM) terminals 2D and 2B. Is the voltage between 1.5-3.5 V?	Yes	Go to the next step.
3		No	Repair or replace the wiring harness between connector C-08 and connector C-69 because the wiring harness is shorted to the power supply.
4	INSPECT CAN LINE BETWEEN CONNECTOR C-69 AND ELECTRICAL SUPPLY UNIT (ESU) FOR SHORT TO POWER SUPPLY Measure the voltage at electrical supply unit (ESU) terminals 1X and 1W. Is the voltage between 1.5-3.5 V?	Yes	Go to Step 6. (with parking sensor system) Go to Step 11. (without parking sensor system)
4		No	Go to the next step.
5	INSPECT PARKING ASSIST UNIT (ULTRASONIC) FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Connect the connector C-58. Disconnect the parking assist unit (ultrasonic) connector. Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off). Measure the voltage at body control module (BCM) terminals 2D and 2B. Is the voltage between 1.5-3.5 V?	Yes	Replace the electrical supply unit (ESU) because there is a short to the power supply in the electrical supply unit (ESU). (See ELECTRICAL SUPPLY UNIT (ESU) REMOVAL/INSTALLATION .)
5		No	Repair or replace the wiring harness between the electrical supply unit (ESU) and connector C-69 because the wiring harness is shorted to the power supply.
6	INSPECT CAN LINE BETWEEN CONNECTOR C-58 AND CONNECTOR C-69 FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Connect the connector C-69. Disconnect the connector C-58. Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off). Measure the voltage at body control module (BCM) terminals 2D and 2B. Is the voltage between 1.5-3.5 V?	Yes	Go to the next step.
6		No	Repair or replace the wiring harness between connector C-58 and connector C-69 because the wiring harness is shorted to the power supply.
7	INSPECT CAN LINE BETWEEN PARKING ASSIST UNIT (ULTRASONIC) AND CONNECTOR C-58 FOR SHORT TO POWER SUPPLY Measure the voltage at parking assist unit (ultrasonic) terminals 1X and 1Z. Is the voltage between 1.5-3.5 V?	Yes	Go to Step 9.
7		No	Go to the next step.
8	INSPECT PARKING ASSIST UNIT (ULTRASONIC) FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Connect the connector C-58. Disconnect the parking assist unit (ultrasonic) connector. Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off). Measure the voltage at body control module (BCM) terminals 2D and 2B. Is the voltage between 1.5-3.5 V?	Yes	Replace the parking assist unit (ultrasonic) because there is a short to the power supply in the parking assist unit (ultrasonic). (See PARKING ASSIST UNIT (ULTRASONIC) REMOVAL/INSTALLATION .)
8		No	Repair or replace the wiring harness between the parking assist unit (ultrasonic) and connector C-58 because the wiring harness is shorted to the power supply.
9	INSPECT CAN LINE BETWEEN REAR SIDE RADAR SENSOR (RH) AND CONNECTOR C-70 FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Connect the connector C-58. Disconnect the connector C-70. Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off). Measure the voltage at body control module (BCM) terminals 2D and 2B. Is the voltage between 1.5-3.5 V?	Yes	Go to the next step.
9		No	Repair or replace the wiring harness between connector C-70 and connector C-58 because the wiring harness is shorted to the power supply.
10	INSPECT REAR SIDE RADAR SENSOR (RH) FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Connect the connector C-60. Disconnect the rear side radar sensor (RH) connector. Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off). Measure the voltage at body control module (BCM) terminals 2D and 2B. Is the voltage between 1.5-3.5 V?	Yes	Replace the rear side radar sensor (RH) because there is a short to the power supply in the rear side radar sensor (RH). (See REAR SIDE RADAR SENSOR REMOVAL/INSTALLATION .)
10		No	Repair or replace the wiring harness between the rear side radar sensor (RH) and connector C-70 because the wiring harness is shorted to the power supply.
11	INSPECT CAN LINE BETWEEN CONNECTOR C-68 AND CONNECTOR C-69 FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Connect the connector C-69. Disconnect the connector C-68. Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off). Measure the voltage at body control module (BCM) terminals 2D and 2B. Is the voltage between 1.5-3.5 V?	Yes	Go to the next step.
11		No	Repair or replace the wiring harness between the connector C-68 and connector C-69 because the wiring harness is shorted to the power supply.
12	INSPECT CAN LINE BETWEEN CONNECTOR C-70 AND CONNECTOR C-68 FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Disconnect the connector C-70. Connect the connector C-68 Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off). Measure the voltage at body control module (BCM) terminals 2D and 2B. Is the voltage between 1.5-3.5 V?	Yes	Go to the next step.
12		No	Repair or replace the wiring harness between the connector C-70 and connector C-68 because the wiring harness is shorted to the power supply.
13	INSPECT REAR SIDE RADAR SENSOR (RH) FOR SHORT TO POWER SUPPLY Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Connect the connector C-70. Disconnect the rear side radar sensor (RH) connector. Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Switch the ignition ON (engine off). Measure the voltage at body control module (BCM) terminals 2D and 2B. Is the voltage between 1.5-3.5 V?	Yes	Replace the rear side radar sensor (RH) because there is a short to the power supply in the rear side radar sensor (RH). (See REAR SIDE RADAR SENSOR REMOVAL/INSTALLATION .)
13		No	Repair or replace the wiring harness between the rear side radar sensor (RH) and connector C-70 because the wiring harness is shorted to the power supply.