In EURO4 diesel engine equipped with CPF, injection is devided into 2 pilot, 1 main, 2 post injections. Among these injections, pilot and main injections are for the operation of engine, however post injections are for CPF regeneration. Only in activating condition of CPF regeneration during driving, post injection starts. 1st post injection happens at the end of combustion cycle then, injected fuel is used to raise exhaust temperature. that temp. is sensed at T3 exhaust tempt. sensor which is ahead of Turbo charger. 2nd post injection happens at exhaust cycle then, injected fuel is also used to raise exhaust temperature. that temp. is sensed T5 exhaust tempt. sensor which is between Oxydation catalyst and CPF. The reason of raising exhaust tempt. is because exhaust tempt. in diesel engine is too low for CPF regeneration. The optimum tempt. for CPF regeneration is 550~600? thus, the goal of post injection is raise exhaust tempt. to that range of tempt.. However if exhaust tempt. is too high, turbo charger or CPF are likely to be damaged. Therefore if temp. measured at each sensor is out of permittable value(specification), ECM deactivates CPF regeneration.
P2030 is set when the temperature difference between front Exhaust temp. sensor(T3) and rear Exhaust temp. sensor(T5) is above 40? at cold idle. This code is set to prevent CPF from damaging due to inaccurate sensing of exhaust gas temp.
DTC Detecting Condition
IG KEY "ON"
| front Exhaust temp.- rear Exhaust temp.
| is above 40? at cold idle.
Temp. governing inhibited
Soot simulation ON mode
Reduced regeneration mileage
Schematic Circuit Diagram
Signal Waveform & Data
Fig.1) 4.8V is outputted at EGTS(T3-VGT) output signal circuit at IG KEY ON.
Fig.2) 4.8V is outputted at EGTS(T5-CPF) output signal circuit at IG KEY ON.
? At IG KEY ON state and as soon as turning engine ON, the difference of output voltage between EGTS(T3-VGT) and
EGTS(T5-CPF) must be small to be neglectable.