DTC C0023:14 [REAR BODY CONTROL MODULE (RBCM)]

id0902p4015100

System malfunction location

Rear body control module (RBCM) internal malfunction (brake light drive circuit)

Detection condition

•  Rear body control module (RBCM) detects open circuit in brake light circuit.

Fail-safe

—

Possible cause

•  DTCs are stored in the PCM.

•  Laser sensor stores DTCs.

•  Brake light relay malfunction

•  Short to ground or open circuit in brake light relay power supply circuit

―  Short to ground in wiring harness between battery positive terminal and brake light relay terminal E

―  Short to ground in wiring harness between battery positive terminal and brake light relay terminal C

―  MAIN 200 A fuse malfunction

―  STOP 10 A fuse malfunction

―  Open circuit in wiring harness between battery positive terminal and brake light relay terminal E

―  Open circuit in wiring harness between battery positive terminal and brake light relay terminal C

•  Brake light (LH) connector or terminal malfunction

•  Brake light bulb (LH) malfunction

•  Open circuit in wiring harness between brake light (LH) terminal C and body ground

•  Brake light (RH) connector or terminal malfunction

•  Brake light bulb (RH) malfunction

•  Open circuit in wiring harness between brake light (RH) terminal C and body ground

•  High-mount brake light connector or terminal malfunction

•  Open circuit in wiring harness between high-mount brake light terminal B and body ground

•  Rear body control module (RBCM) connector or terminal malfunction

•  Short to ground in wiring harness between the following terminals:

―  Brake light relay terminal A and rear body control module (RBCM) terminal 2H

―  Rear body control module (RBCM) terminal 4D and brake light (LH) terminal B

―  Rear body control module (RBCM) terminal 4D and brake light (RH) terminal B

―  Rear body control module (RBCM) terminal 4D and high-mount brake light terminal A

•  Short to power supply in wiring harness between the following terminals:

―  Brake light relay terminal A and rear body control module (RBCM) terminal 2H

―  Rear body control module (RBCM) terminal 4D and brake light (LH) terminal B

―  Rear body control module (RBCM) terminal 4D and brake light (RH) terminal B

―  Rear body control module (RBCM) terminal 4D and high-mount brake light terminal A

•  Open circuit in wiring harness between the following terminals:

―  Brake light relay terminal A and rear body control module (RBCM) terminal 2H

―  Brake light relay terminal D and rear body control module (RBCM) terminal 4D

―  Rear body control module (RBCM) terminal 4D and brake light (LH) terminal B

―  Rear body control module (RBCM) terminal 4D and brake light (RH) terminal B

―  Rear body control module (RBCM) terminal 4D and high-mount brake light terminal A

•  High-mount brake light malfunction

•  Rear body control module (RBCM) malfunction

System malfunction location	Rear body control module (RBCM) internal malfunction (brake light drive circuit)
Detection condition	• Rear body control module (RBCM) detects open circuit in brake light circuit.
Fail-safe	—
Possible cause	• DTCs are stored in the PCM. • Laser sensor stores DTCs. • Brake light relay malfunction • Short to ground or open circuit in brake light relay power supply circuit ― Short to ground in wiring harness between battery positive terminal and brake light relay terminal E ― Short to ground in wiring harness between battery positive terminal and brake light relay terminal C ― MAIN 200 A fuse malfunction ― STOP 10 A fuse malfunction ― Open circuit in wiring harness between battery positive terminal and brake light relay terminal E ― Open circuit in wiring harness between battery positive terminal and brake light relay terminal C • Brake light (LH) connector or terminal malfunction • Brake light bulb (LH) malfunction • Open circuit in wiring harness between brake light (LH) terminal C and body ground • Brake light (RH) connector or terminal malfunction • Brake light bulb (RH) malfunction • Open circuit in wiring harness between brake light (RH) terminal C and body ground • High-mount brake light connector or terminal malfunction • Open circuit in wiring harness between high-mount brake light terminal B and body ground • Rear body control module (RBCM) connector or terminal malfunction • Short to ground in wiring harness between the following terminals: ― Brake light relay terminal A and rear body control module (RBCM) terminal 2H ― Rear body control module (RBCM) terminal 4D and brake light (LH) terminal B ― Rear body control module (RBCM) terminal 4D and brake light (RH) terminal B ― Rear body control module (RBCM) terminal 4D and high-mount brake light terminal A • Short to power supply in wiring harness between the following terminals: ― Brake light relay terminal A and rear body control module (RBCM) terminal 2H ― Rear body control module (RBCM) terminal 4D and brake light (LH) terminal B ― Rear body control module (RBCM) terminal 4D and brake light (RH) terminal B ― Rear body control module (RBCM) terminal 4D and high-mount brake light terminal A • Open circuit in wiring harness between the following terminals: ― Brake light relay terminal A and rear body control module (RBCM) terminal 2H ― Brake light relay terminal D and rear body control module (RBCM) terminal 4D ― Rear body control module (RBCM) terminal 4D and brake light (LH) terminal B ― Rear body control module (RBCM) terminal 4D and brake light (RH) terminal B ― Rear body control module (RBCM) terminal 4D and high-mount brake light terminal A • High-mount brake light malfunction • Rear body control module (RBCM) malfunction

Diagnostic Procedure

Step	Inspection		Action
1	VERIFY REAR BODY CONTROL MODULE (RBCM) DTCs AGAIN • Clear rear body control module (RBCM) DTCs using the M-MDS. (See CLEARING DTC [REAR BODY CONTROL MODULE (RBCM)].) • Perform the DTC inspection for the rear body control module (RBCM) using the M-MDS. (See DTC INSPECTION [REAR BODY CONTROL MODULE (RBCM)].) • Is DTC C0023:14 displayed?	Yes	Go to the next step.
1		No	Go to Step 20.
2	VERIFY PCM DTCs • Perform the DTC inspection for the PCM using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-D 2.2].) • Is the DTC displayed?	Yes	Repair the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See DTC TABLE [SKYACTIV-D 2.2].)
2		No	Go to the next step.
3	VERIFY LASER SENSOR DTCs • Perform the DTC inspection for the laser sensor using the M-MDS. (See ON-BOARD DIAGNOSIS [LASER SENSOR].) • Is the DTC displayed?	Yes	Repair the malfunctioning part according to the applicable DTC troubleshooting. (See ON-BOARD DIAGNOSIS [LASER SENSOR].)
3		No	Go to the next step.
4	INSPECT BRAKE LIGHT RELAY FOR MALFUNCTION • Switch the ignition to off. • Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5 (WITHOUT i-stop)].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) • Remove the brake light relay. (See RELAY LOCATION.) • Inspect the brake light relay. (See RELAY INSPECTION.) • Is the brake light relay normal?	Yes	Go to the next step.
4		No	Replace the brake light relay, then go to Step 19. (See RELAY LOCATION.)
5	INSPECT BRAKE LIGHT RELAY POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND • Verify that the brake light relay is removed. • Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5 (WITHOUT i-stop)].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) • Switch the ignition ON (engine off or on). • Measure the voltage at the following terminals (vehicle wiring harness side). ― Brake light relay terminal E ― Brake light relay terminal C • Is the voltage B+?	Yes	Install the brake light relay, then go to the next step.
5		No	Inspect the MAIN 200 A fuse and STOP 10 A fuse. • If a fuse is burnt out: ― Repair or replace the wiring harness which is shorted to ground. ― Replace the burnt out fuse. • If a fuse is damaged: ― Replace the damaged fuse. • All fuses are normal: ― Repair or replace the wiring harness which has an open circuit. Go to Step 19.
6	INSPECT BRAKE LIGHT (LH) CONNECTOR • Switch the ignition to off. • Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5 (WITHOUT i-stop)].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) • Disconnect the brake light (LH) connector. • Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. • Is the connector normal?	Yes	Go to the next step.
6		No	Repair or replace the connector, then go to Step 19.
7	INSPECT BRAKE LIGHT BULB (LH) • Inspect the brake light bulb (LH). • Is the brake light bulb (LH) normal?	Yes	Go to the next step.
7		No	Replace the brake/taillight bulb (LH), then go to Step 19. (See BRAKE/TAILLIGHT BULB REMOVAL/INSTALLATION.)
8	INSPECT BRAKE LIGHT (LH) GROUND CIRCUIT FOR OPEN CIRCUIT • Verify that the brake light (LH) connector is disconnected. • Inspect for continuity between brake light (LH) terminal C (vehicle wiring harness side) and body ground. • Is there continuity?	Yes	Go to the next step.
8		No	Repair or replace the wiring harness and go to Step 19.
9	INSPECT BRAKE LIGHT (RH) CONNECTOR • Disconnect the brake light (RH) connector. • Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. • Is the connector normal?	Yes	Go to the next step.
9		No	Repair or replace the connector, then go to Step 19.
10	INSPECT BRAKE LIGHT BULB (RH) • Inspect the brake light bulb (RH). • Is the brake light bulb (RH) normal?	Yes	Go to the next step.
10		No	Replace the brake/taillight bulb (RH), then go to Step 19. (See BRAKE/TAILLIGHT BULB REMOVAL/INSTALLATION.)
11	INSPECT BRAKE LIGHT (RH) GROUND CIRCUIT FOR OPEN CIRCUIT • Verify that the brake light (RH) connector is disconnected. • Inspect for continuity between brake light (RH) terminal C (vehicle wiring harness side) and body ground. • Is there continuity?	Yes	Go to the next step.
11		No	Repair or replace the wiring harness and go to Step 19.
12	INSPECT HIGH-MOUNT BRAKE LIGHT CONNECTOR • Disconnect the high-mount brake light connector. • Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. • Is the connector normal?	Yes	Go to the next step.
12		No	Repair or replace the connector, then go to Step 19.
13	INSPECT HIGH-MOUNT BRAKE LIGHT GROUND CIRCUIT FOR OPEN CIRCUIT • Verify that the high-mount brake light connector is disconnected. • Inspect for continuity between high-mount brake light terminal B (vehicle wiring harness side) and body ground. • Is there continuity?	Yes	Go to the next step.
13		No	Repair or replace the wiring harness and go to Step 19.
14	INSPECT REAR BODY CONTROL MODULE (RBCM) CONNECTOR CONDITION • Disconnect the rear body control module (RBCM) connector. • Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. • Is the connector normal?	Yes	Go to the next step.
14		No	Repair or replace the connector, then go to Step 19.
15	INSPECT BRAKE LIGHT DRIVE CIRCUIT FOR SHORT TO GROUND • Verify that the brake light (LH)/(RH) connector, high-mount brake light connector, and rear body control module (RBCM) connector are disconnected. • Inspect for continuity between the following terminals (vehicle wiring harness side) and body ground. ― Rear body control module (RBCM) terminal 2H ― Brake light (LH) terminal B ― Brake light (RH) terminal B ― High-mount brake light terminal A • Is there continuity?	Yes	Repair or replace the wiring harness which is shorted to ground, then go to Step 19.
15		No	Go to the next step.
16	INSPECT BRAKE LIGHT DRIVE CIRCUIT FOR SHORT TO POWER SUPPLY • Verify that the brake light (LH)/(RH) connector, high-mount brake light connector, and rear body control module (RBCM) connector are disconnected. • Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5 (WITHOUT i-stop)].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) • Switch the ignition ON (engine off or on). • Measure the voltage at the following terminals (vehicle wiring harness side). ― Rear body control module (RBCM) terminal 2H ― Brake light (LH) terminal B ― Brake light (RH) terminal B ― High-mount brake light terminal A • Is the voltage 0 V?	Yes	Go to the next step.
16		No	Repair or replace the wiring harness which is shorted to power supply, then go to Step 19.
17	INSPECT BRAKE LIGHT DRIVE CIRCUIT FOR OPEN CIRCUIT • Verify that the brake light (LH)/(RH) connector, high-mount brake light connector, and rear body control module (RBCM) connector are disconnected. • Switch the ignition to off. • Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5 (WITHOUT i-stop)].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) • Inspect the wiring harness between the following terminals (vehicle wiring harness side) for continuity. ― Brake light relay terminal A and rear body control module (RBCM) terminal 2H ― Brake light relay terminal D and rear body control module (RBCM) terminal 4D ― Rear body control module (RBCM) terminal 4D and brake light (LH) terminal B ― Rear body control module (RBCM) terminal 4D and brake light (RH) terminal B ― Rear body control module (RBCM) terminal 4D and high-mount brake light terminal A • Is there continuity?	Yes	Go to the next step.
17		No	Repair or replace the wiring harness which has an open circuit, then go to Step 19.
18	PERFORM DTC INSPECTION AND VERIFY IF MALFUNCTIONING PART IS HIGH-MOUNT BRAKE LIGHT • Reconnect all the disconnected connectors. • Reconnect the disconnected negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5 (WITHOUT i-stop)].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) • Clear rear body control module (RBCM) DTCs using the M-MDS. (See CLEARING DTC [REAR BODY CONTROL MODULE (RBCM)].) • Perform the DTC inspection for the rear body control module (RBCM) using the M-MDS. (See DTC INSPECTION [REAR BODY CONTROL MODULE (RBCM)].) • Is DTC C0023:14 displayed?	Yes	Replace the high-mount brake light, then go to the next step. (See HIGH-MOUNT BRAKE LIGHT REMOVAL/INSTALLATION.)
18		No	Go to Step 20.
19	VERIFY THAT REPAIRS HAVE BEEN COMPLETED • Reconnect all the disconnected connectors. • Reconnect the disconnected negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5 (WITHOUT i-stop)].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) • Clear rear body control module (RBCM) DTCs using the M-MDS. (See CLEARING DTC [REAR BODY CONTROL MODULE (RBCM)].) • Perform the DTC inspection for the rear body control module (RBCM) using the M-MDS. (See DTC INSPECTION [REAR BODY CONTROL MODULE (RBCM)].) • Is DTC C0023:14 displayed?	Yes	Repeat the inspection from Step 1. • If the malfunction recurs, replace the rear body control module (RBCM), then go to the next step. (See REAR BODY CONTROL MODULE (RBCM) REMOVAL/INSTALLATION.)
19		No	Go to the next step.
20	VERIFY IF OTHER DTCs DISPLAYED • Are any other DTCs displayed?	Yes	Repair the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [REAR BODY CONTROL MODULE (RBCM)].)
20		No	DTC troubleshooting completed.