DTC P21CB:00 [DOSING CONTROL UNIT (SKYACTIV-D 2.2)]

id0102k1725100

DTC P21CB:00

Dosing control unit power supply voltage low input

DETECTION CONDITION

•  If the dosing control unit detects that the power supply voltage is less than 8 V for 10 s, the dosing control unit determines that the power supply voltage circuit has a malfunction.

MONITORING CONDITIONS

―  Ignition switched ON (engine off or on)

Note

•  DTC P1640:00 is also stored in the PCM.

Diagnostic support note

•  This is a continuous monitor (CCM).

•  The check engine light illuminates if the dosing control unit detects the above malfunction condition during the first drive cycle.

•  FREEZE FRAME DATA / Snapshot data is available.

•  DTC is stored in the dosing control unit memory.

FAIL-SAFE FUNCTION

•  Not applicable

POSSIBLE CAUSE

•  Battery malfunction

•  SCR relay No.1 malfunction

•  Dosing control unit power supply circuit malfunction

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

•  MAIN 200 A fuse—SCR relay No.1 terminal A

•  MAIN 200 A fuse—SCR relay No.1 terminal D

―  MAIN 200 A fuse malfunction

―  SCR1 20 A fuse malfunction

―  Open circuit in wiring harness between the following terminals:

•  Battery positive terminal—SCR relay No.1 terminal A

•  Battery positive terminal—SCR relay No.1 terminal D

•  Dosing control unit connector or terminals malfunction

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

―  SCR relay No.1 terminal C—dosing control unit terminal B

―  SCR relay No.1 terminal C—dosing control unit terminal C

•  Open circuit in wiring harness between the following terminals:

―  SCR relay No.1 terminal E—dosing control unit terminal BV

―  SCR relay No.1 terminal C—dosing control unit terminal B

―  SCR relay No.1 terminal C—dosing control unit terminal C

•  Dosing control unit malfunction

DTC P21CB:00	Dosing control unit power supply voltage low input
DETECTION CONDITION	• If the dosing control unit detects that the power supply voltage is less than 8 V for 10 s, the dosing control unit determines that the power supply voltage circuit has a malfunction. MONITORING CONDITIONS ― Ignition switched ON (engine off or on) Note • DTC P1640:00 is also stored in the PCM. Diagnostic support note • This is a continuous monitor (CCM). • The check engine light illuminates if the dosing control unit detects the above malfunction condition during the first drive cycle. • FREEZE FRAME DATA / Snapshot data is available. • DTC is stored in the dosing control unit memory.
FAIL-SAFE FUNCTION	• Not applicable
POSSIBLE CAUSE	• Battery malfunction • SCR relay No.1 malfunction • Dosing control unit power supply circuit malfunction ― Short to ground in wiring harness between the following terminals: • MAIN 200 A fuse—SCR relay No.1 terminal A • MAIN 200 A fuse—SCR relay No.1 terminal D ― MAIN 200 A fuse malfunction ― SCR1 20 A fuse malfunction ― Open circuit in wiring harness between the following terminals: • Battery positive terminal—SCR relay No.1 terminal A • Battery positive terminal—SCR relay No.1 terminal D • Dosing control unit connector or terminals malfunction • Short to ground in wiring harness between the following terminals: ― SCR relay No.1 terminal C—dosing control unit terminal B ― SCR relay No.1 terminal C—dosing control unit terminal C • Open circuit in wiring harness between the following terminals: ― SCR relay No.1 terminal E—dosing control unit terminal BV ― SCR relay No.1 terminal C—dosing control unit terminal B ― SCR relay No.1 terminal C—dosing control unit terminal C • Dosing control unit malfunction

Diagnostic Procedure

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY RELATED REPAIR INFORMATION AVAILABILITY • Verify related Service Information availability. • Is any related Service Information available?	Yes	Perform repair or diagnosis according to the available Service Information. • If the vehicle is not repaired, go to the next step.
1		No	Go to the next step.
2	INSPECT BATTERY • Inspect the battery. (See BATTERY INSPECTION.) • Is there any malfunction?	Yes	Recharge or replace the battery, then go to Step 8. (See BATTERY RECHARGING.) (See BATTERY REMOVAL/INSTALLATION [SKYACTIV-D 2.2].)
2		No	Go to the next step.
3	INSPECT SCR RELAY No.1 • Switch the ignition off. • Remove the SCR relay No.1. (See RELAY LOCATION.) • Inspect the SCR relay No.1. (See RELAY INSPECTION.) • Is there any malfunction?	Yes	Replace the SCR relay No.1, then go to Step 8. (See RELAY LOCATION.)
3		No	Go to the next step.
4	INSPECT DOSING CONTROL UNIT POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT • Verify that the SCR relay No.1 is removed. • Switch the ignition ON (engine off). Note • Another DTC may be stored by the dosing control unit detecting an open circuit. • Measure the voltage at the following terminals (wiring harness-side): ― SCR relay No.1 terminal A ― SCR relay No.1 terminal D • Is the voltage 0 V?	Yes	Inspect the MAIN 200 A fuse and SCR1 20 A fuse. • If the fuse is blown: ― Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals: • MAIN 200 A fuse—SCR relay No.1 terminal A • MAIN 200 A fuse—SCR relay No.1 terminal D If there is a common connector: • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground. • Repair or replace the malfunctioning part. If there is no common connector: • Repair or replace the wiring harness which has a short to ground. • Replace the malfunctioning fuse. • If the fuse is damaged: ― Replace the malfunctioning fuse. • If all fuses are normal: ― Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals: • Battery positive terminal—SCR relay No.1 terminal A • Battery positive terminal—SCR relay No.1 terminal D If there is a common connector: • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit. • Repair or replace the malfunctioning part. If there is no common connector: • Repair or replace the wiring harness which has an open circuit. Go to Step 8.
4		No	Go to the next step.
5	INSPECT DOSING CONTROL UNIT CONNECTOR CONDITION • Switch the ignition off. • Disconnect the dosing control unit connector. • Inspect for poor connection (such as damaged/pulled-out pins, corrosion). • Is there any malfunction?	Yes	Repair or replace the connector and/or terminals, then go to Step 8.
5		No	Go to the next step.
6	INSPECT DOSING CONTROL UNIT POWER SUPPLY CIRCUIT FOR SHORT TO GROUND • Verify that the SCR relay No.1 is removed. • Verify that the dosing control unit connector is disconnected. • Inspect for continuity between the SCR relay No.1 terminal C (wiring harness-side) and body ground. • Is there continuity?	Yes	Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals: • SCR relay No.1 terminal C—dosing control unit terminal B • SCR relay No.1 terminal C—dosing control unit terminal C If there is a common connector: • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground. • Repair or replace the malfunctioning part. If there is no common connector: • Repair or replace the wiring harness which has a short to ground. Go to Step 8.
6		No	Go to the next step.
7	INSPECT DOSING CONTROL UNIT POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT • Verify that the SCR relay No.1 is removed. • Verify that the dosing control unit connector is disconnected. • Inspect for continuity between the following terminals (wiring harness-side). ― SCR relay No.1 terminal E—dosing control unit terminal BV ― SCR relay No.1 terminal C—dosing control unit terminal B ― SCR relay No.1 terminal C—dosing control unit terminal C • Is there continuity?	Yes	Go to the next step.
7		No	Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals: • SCR relay No.1 terminal E—dosing control unit terminal BV • SCR relay No.1 terminal C—dosing control unit terminal B • SCR relay No.1 terminal C—dosing control unit terminal C If there is a common connector: • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit. • Repair or replace the malfunctioning part. If there is no common connector: • Repair or replace the wiring harness which has an open circuit. Go to the next step.
8	VERIFY DTC TROUBLESHOOTING COMPLETED • Always reconnect all disconnected connectors. • Clear the DTC from the dosing control unit memory using the M-MDS. (See CLEARING DTC [DOSING CONTROL UNIT (SKYACTIV-D 2.2)].) • Idle the engine for 30 s. • Retrieve the dosing control unit DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [DOSING CONTROL UNIT (SKYACTIV-D 2.2)].) • Is the same Pending DTC present?	Yes	Repeat the inspection from Step 1. • If the malfunction recurs, replace the dosing control unit. (See DOSING CONTROL UNIT REMOVAL/INSTALLATION [SKYACTIV-D 2.2].) Go to the next step.
8		No	Go to the next step.
9	VERIFY IF OTHER DTCs DISPLAYED • Are any other DTCs displayed?	Yes	Repair or replace the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [DOSING CONTROL UNIT (SKYACTIV-D 2.2)].)
9		No	DTC troubleshooting completed.