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DTC U0121:00 [PCM (SKYACTIV-D)]

id0102t5327700

Outline

System malfunction location

CAN communication: communication error to DSC HU/CM

Detection condition

•  Communication error between the PCM and DSC HU/CM continues for 5 s or more.

―  Battery voltage: 10 V or more

―  1.5 s have elapsed after ignition is switched ON (engine off or on)

Fail-safe

•  PCM restricts engine torque./Limits the maximum engine speed.

•  Inhibits the DENOx/DESOx control.

•  Inhibits the compulsory diesel particulate filter regeneration control.

•  Inhibits the EGR control.

•  Inhibits engine-stop by operating the i-stop function.

Possible cause

•  CAN communication line malfunction between PCM and DSC HU/CM

•  DSC HU/CM malfunction

•  PCM malfunction

System wiring diagram

•  Not applicable

Connector diagram

•  Not applicable

System malfunction location	CAN communication: communication error to DSC HU/CM
Detection condition	• Communication error between the PCM and DSC HU/CM continues for 5 s or more. ― Battery voltage: 10 V or more ― 1.5 s have elapsed after ignition is switched ON (engine off or on)
Fail-safe	• PCM restricts engine torque./Limits the maximum engine speed. • Inhibits the DENOx/DESOx control. • Inhibits the compulsory diesel particulate filter regeneration control. • Inhibits the EGR control. • Inhibits engine-stop by operating the i-stop function.
Possible cause	• CAN communication line malfunction between PCM and DSC HU/CM • DSC HU/CM malfunction • PCM malfunction
System wiring diagram	• Not applicable
Connector diagram	• Not applicable

Diagnostic Procedure

• Inspect according to the diagnostic procedure in ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].)