DTC B112A:12 [START STOP UNIT]

id0902p6020500

System malfunction location

IG2 relay circuit malfunction

Detection condition

•  With the ignition switched off or to ACC, the start stop unit detects IG2 relay circuit voltage of 2.5 V or more for 0.5 s or more.

Fail-safe

—

Possible cause

•  Front body control module (FBCM) connector or terminal malfunction

•  Start stop unit connector or terminal malfunction

•  Short to power supply in wiring harness between start stop unit terminal 2D and front body control module (FBCM) terminal 2U

•  Front body control module (FBCM) malfunction

•  Start stop unit malfunction

System malfunction location	IG2 relay circuit malfunction
Detection condition	• With the ignition switched off or to ACC, the start stop unit detects IG2 relay circuit voltage of 2.5 V or more for 0.5 s or more.
Fail-safe	—
Possible cause	• Front body control module (FBCM) connector or terminal malfunction • Start stop unit connector or terminal malfunction • Short to power supply in wiring harness between start stop unit terminal 2D and front body control module (FBCM) terminal 2U • Front body control module (FBCM) malfunction • Start stop unit malfunction

Diagnostic Procedure

Step	Inspection		Action
1	INSPECT FRONT BODY CONTROL MODULE (FBCM) CONNECTOR CONDITION • 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 front body control module (FBCM) 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.
1		No	Repair or replace the connector, then go to Step 5.
2	INSPECT START STOP UNIT CONNECTOR CONDITION • Disconnect the start stop unit 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.
2		No	Repair or replace the connector, then go to Step 5.
3	INSPECT IG2 RELAY CIRCUIT FOR SHORT TO POWER SUPPLY • Reconnect all the disconnected connectors. • 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].) • Measure the voltage at front body control module (FBCM) terminal 2U (vehicle wiring harness side). • Is the voltage 2.5 V or more?	Yes	Repair or replace the wiring harness which is shorted to power supply, then go to Step 5.
3		No	Go to the next step.
4	PERFORM DTC INSPECTION AND VERIFY IF IG2 RELAY IS MALFUNCTIONING PART • Clear DTC for the start stop unit using the M-MDS. (See CLEARING DTC [START STOP UNIT].) • Switch the ignition to off or to ACC, and wait for 0.5 s or more. • Perform the DTC inspection for the start stop unit using the M-MDS. (See DTC INSPECTION [START STOP UNIT].) • Is DTC B112A:12 displayed?	Yes	Replace the front body control module (FBCM), then go to the next step. (See FRONT BODY CONTROL MODULE (FBCM) REMOVAL/INSTALLATION.)
4		No	Go to Step 6.
5	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 DTC for the start stop unit using the M-MDS. (See CLEARING DTC [START STOP UNIT].) • Switch the ignition to off or to ACC, and wait for 0.5 s or more. • Perform the DTC inspection for the start stop unit using the M-MDS. (See DTC INSPECTION [START STOP UNIT].) • Is DTC B112A:12 displayed?	Yes	Repeat the inspection from Step 1. • If the malfunction recurs, replace the start stop unit, then go to the next step. (See START STOP UNIT REMOVAL/INSTALLATION.)
5		No	Go to the next step.
6	VERIFY IF OTHER DTCs DISPLAYED • Are any other DTCs displayed?	Yes	Repair the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [START STOP UNIT].)
6		No	DTC troubleshooting completed.