Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
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36.
DTC P1070 Catalytic converter is clogged.
P2002 Catalytic converter is removed.
P2454 Catalytic converter front and rear differential pressure is too low.
P2455 Catalytic converter front and rear differential pressure is too high.
Differential pressure sensor is a Hall Effect switch. ECU provides differential pressure sensor with 5V voltage via 5V
reference voltage circuit and provides the sensor with grounding via low reference voltage circuit. Differential
pressure sensor provides ECU with signal voltage according to front and rear differential pressure changes of catalytic
converter. ECU determines catalytic converter differential pressure with this signal voltage. Differential pressure
sensor circuit is connected to ECU directly. Moreover, differential pressure sensor can be applied in determination of
catalytic converter damages. Circuits between differential pressure sensor and ECU include the followings:
Differential pressure sensor high reference voltage circuit
Ground circuit
Differential pressure signal circuit
When ECU detects incorrect sensor signals or no signals, DTC occurs.
Diagnosis Hint: Poor terminal connection—Check harness connectors for looseness, mismatching, retainer damage,
improper shape or damage and connection failure with wires. Apply corresponding matching terminals for test of
proper tension.
Harness damage—Check wire harness for damage. In the case of no harness faults, move relevant connectors and
wire harness and observe display of fault diagnostic apparatus. Fault diagnostic apparatus displays changes to indicate
fault positions.
Check ECU and engine ground connection for reliability and cleanness. If it is determined that DTC is an intermittent
fault, please refer to Fault Record to check the time of last DTC occurrence.
Terminal ECU
K27 Differential pressure sensor power supply
K59 Differential pressure sensor signal terminal
K80 Ground
Differential
pressure
sensor
5V power supply
Differential pressure signal
Groun
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