3.
Monitor the "Parameters related to air/fuel ratio(HO2S, MAF, MAP, TPS, ECTS, PCSV, Injector, etc)" on the scantool.
The catalyst’s efficiency is demonstrated by its ability to oxidize CO and hydrocarbon emissions. The Powertrain Control Module (PCM) compares the output signals of the front and rear oxygen sensors to determine whether the output of the rear sensor is beginning to match the output of the front oxygen sensor. Air/fuel mixture compensation keeps the frequency of the front oxygen sensor high due to the changes from rich-to-lean combusition. The catalyst causes the rear oxygen sensor to have a lower frequency. As the catalyst wears, the rear oxygen sensor’s signal trace begins to match the front oxygen sensor’s signal trace. That is because the catalyst becomes saturated with oxygen and cannot use the oxygen to convert hydrocarbon and CO into H₂O and CO₂ with the same efficiency as when it was new. A completely worn catalyst shows a 100% match between the frequency of the front and rear sensors.
ECM controls Air/Fuel ratio by B1S1 monitoring and B1S2 monitoring. By the way, if there is the retarded B1S1 signal line shift compared with the value of B1S2 controller, PCM sets DTC P2097.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● O2 sensor characteristic line shift | ● Catalyst converter ● B1S1 ● ECM |
Enable Conditions | ● Dew point end detected ● Required lambda = 1 ● Battery voltage 〉 10.7V ● Exhaust gas temperature (model) 〈 800℃ ● Heater control enabled ● 1200rpm 〈 Engine speed 〈 3520rpm ● Engine load : 15 ~ 78 % | |
Threshold Value | ● The second controller by B1S2 〉-1sec | |
Diagnostic Time | ● 15 sec | |
MIL ON Condition | ● 2 driving cycle |
※ B1S1 : upstream oxygen sensor / B1S2 : downstream oxygen sensor
Connect scantool to Data Link Connector(DLC).
Warm up the engine to normal operating temperature.
Monitor the "Parameters related to air/fuel ratio(HO2S, MAF, MAP, TPS, ECTS, PCSV, Injector, etc)" on the scantool.
Are the parameters displayed correctly?
▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or wasrepaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poorconnection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of vehicle Repair" procedure.
▶ Go to "System Inspection" procedure.
Check clog on Exhaust gas system
Key "OFF".
Check clog on muffler or catalyst converter.
Is Exhaust gas system O.K?
▶ Go to "Intake air system check" procedure.
▶ Repair as necessary and go to "Verification of vehicle Repair" procedure.
Intake air system check.
Check clog on Intake air system"
▶ Check clog of air-cleaner.
▶ Check deterioration or contamination on throttle body and gasket.
▶ Check contamination, damage, stuck or clog on intake manifold, hoses, PCSV, ISCA and injectors.
Is there any problem?
▶ Repair as necessary and go to "Verification of vehicle Repair" procedure
▶ Go to "Fuel line check" procedure.
Fuel line pressure check.
Key "OFF".
Disconnect a fuel pump relay.
Engine start and wait until engine stop. and then key "OFF".
Connect a fuel pump relay.
Connect a fuel pressure guage to a fuel filter by a fuel pressure guage adaptor.
Engine start and measure a fuel pressure.
Specification : Approx. 3.5 kg/cm²
Is the fuel pressure normal?
▶ Go to "Component inspection" procedure.
▶ Check clog or stuck of the valve in a fuel pressure regulator.
▶ Check the supply pressure of fuel pump.
▶ Repair as necessary and go to "Verification of vehicle Repair" procedure.
PCV(Positive Crankcase Ventilation) valve check.
Key "OFF".
Disconnect PCV valve.
Check the movement of plunger by putting in and out a thin stick.
Is the movement of plunger normal?
▶ Go to "PCSV check" procedure.
▶ Substitute with a known - good PCV valve and check for proper operation.
▶ If the problem is corrected, replace PCV valve and go to "Verification of Vehicle Repair" procedure.
PCSV check.
Key "OFF".
Disconnect PCSV and vacuum hose.
Apply a vacuum by a hand vacuum gauge on PCSV.
Does PCSV keep the vacuum condition normally?
▶ Go to "Injector check" procedure.
▶ Substitute with a known - good PCSV and check for proper operation.
▶ If the problem is corrected, replace PCSV and go to "Verification of Vehicle Repair" procedure.
Injector check
Key "OFF".
Disconnect injectors.
Check clog on injectors.
Measure the resistance between terminal 1 and 2 of injectors(Component side).
ITEM | Specification |
Coil Resistance | 13.8 ~15.2Ω at 20℃ (68℉) |
Is the measured resistance within specifications ?
▶ Go to "Sensors related to air/fuel ratio check" procedure.
▶ Substitute with a known - good Injector and check for proper operation.
▶ If the problem is corrected, replace Injector and go to "Verification of Vehicle Repair" procedure.
Sensors related to air/fuel ratio check.
Check the output data of sensors related to air/fuel ratio (HO2S, MAPS, TPS, ECTS, PCSV, Injectors, etc) on scantool. (Refer to each DTC guide procedure.)
Are those sensors normal?
▶ Substitute with a known - good ECM and check for proper operation.
▶ If the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure.
Repair or replace as necessary. And then, go to "Verification of Vehicle Repair" procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.
Clear the DTCs and Operate the vehicle within DTC Enable conditions in General information.
Are any DTCs present ?
▶ Go to the applicable troubleshooting procedure.
▶ System is performing to specification at this time.
