P1412/4: Failure A With Egr Valve (Step Motor B-Phase) - Yanmar 3TNV82A Troubleshooting Manual

FAILURE DIAGNOSIS

(3) P1412/4: Failure A with EGR valve (Step Motor B-phase)

DTC P1412/4
DTC Detecting Conditions
1 - Precondition; 2 - Detecting condition(s);
3 - Flashing pattern of failure indicator
1. Key switch ON.
2. Make an assessment logically as to followings.E-ECU detects
the EGR step motor B-phase turning ON during the command to
turn OFF the EGR step motor B-phase.
3. One flash followed by three flashes.
Movement at Error occurrence
Error Mode [Run As Is]:
After detecting the error, the system lets
the engine continue to run without any
restrictions.
Run restricted? No.
Recovery No.
Conditions
Remarks
Estimation of Failure cause/Error condition
• The connector may not be properly connected.
• Wiring defect of the harness
The EGR step motor B-phase wiring may be disconnected or short-circuited with GND.
•
The EGR step motor power supply line may be disconnected.
•
• The EGR step motor may be faulty.
Inner wiring of the EGR step motor B-phase may be disconnected or short-circuited with GND.
•
Power supply line in the EGR step motor may be disconnected.
•
• The E-ECU internal circuitry may be faulty.
1-88
DTCs (Diagnostic Trouble Codes) General Description
Failure A with EGR valve (Step Motor B-Phase)
Movement setting at the EGR step motor error
Unavailable
Check points
Connector
Harness
EGR valve (step motor)
E-ECU
Available
[Run Under Restrictions]:
The engine continues to run under
restrictions.
Yes: The system restricts the High idle
speed or engine power.
No.
TNV DI Service Manual