YH4
GRAND
VITARA
6-84
ENGINE DIAGNOSIS (G16 / J20 ENGINES)
1. Heated oxygen sensor-1
2. Heated oxygen sensor-2
3. Warm up three way catalytic converter
(WU-TWC, if equipped)
4. Three way catalytic converter
DTC P0420 CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD
SYSTEM DIAGRAM
CIRCUIT DESCRIPTION
Exhaust oxygen concentration at the pre-TWC and the post-TWC is detected from HO2S-1 and HO2S-2 respec-
tively and accordingly ECM (PCM) controls the closed loop which then controls the fuel injection volume. (Refer
to Section 6E1.) While the above control is going on and if TWC is in good condition, the output voltage of HO2S-2
is maintained at specified level. As TWC becomes deteriorated, even when the above control is going on, the ex-
haust gas which has passed TWC then passes HO2S-2 at the exhaust oxygen concentration similar to that of the
pre-catalyst without being oxygenated or converted. Thus, waveforms of HO2S-1 and HO2S-2 output voltages
become alike. ECM (PCM) judges deterioration of TWC by comparing waveforms of HO2S-1 and HO2S-2.
DTC DETECTING CONDITION AND TROUBLE AREA
DTC DETECTING CONDITION
TROUBLE AREA
While running under conditions described for DTC
CONFIRMATION PROCEDURE, output waveform of
HO2S-1 becomes similar to that of HO2S-2.
(2 driving cycles detection logic)
Exhaust gas leakage
Three way catalytic convertor
Heated oxygen sensor – 2 or its circuit
ECM (PCM)
Содержание 2000 Grand Vitara SQ416
Страница 75: ...ENGINE DIAGNOSIS G16 J20 ENGINES 6 71 Fig 1 for Step 3...
Страница 179: ...6 1 68 ENGINE H25 ENGINE a Fig for STEP 2 3 a HO2S heater relay...
Страница 190: ...ENGINE H25 ENGINE 6 1 79 a Fig for STEP 2 3 a HO2S heater relay...
Страница 205: ...6 1 94 ENGINE H25 ENGINE Fig for STEP 4 1 Disconnected CMP sensor coupler 2 BI B wire terminal 3 Gr Y wire terminal...
Страница 541: ...6E1 4 ENGINE AND EMISSION CONTROL SYSTEM G16 J20 ENGINES G16 ENGINE...
Страница 542: ...ENGINE AND EMISSION CONTROL SYSTEM G16 J20 ENGINES 6E1 5...
Страница 543: ...6E1 6 ENGINE AND EMISSION CONTROL SYSTEM G16 J20 ENGINES J20 ENGINE...
Страница 544: ...ENGINE AND EMISSION CONTROL SYSTEM G16 J20 ENGINES 6E1 7...
Страница 549: ...Or W Bl G Bl Y C51 1 22 C51 1 23 C51 1 10 C51 1 11 6E1 12 ENGINE AND EMISSION CONTROL SYSTEM G16 J20 ENGINES...
Страница 552: ...ENGINE AND EMISSION CONTROL SYSTEM G16 J20 ENGINES 6E1 15...
Страница 592: ...6E2 4 ENGINE AND EMISSION CONTROL SYSTEM H25 ENGINE...
Страница 593: ...ENGINE AND EMISSION CONTROL SYSTEM H25 ENGINE 6E2 5...
Страница 597: ...ENGINE AND EMISSION CONTROL SYSTEM H25 ENGINE 6E2 9...
Страница 661: ...IGNITION SYSTEM FOR J20 H25 ENGINES 6F2 13 INSTALLATION For installation reverse removal procedure...
Страница 723: ...6H 30 CHARGING SYSTEM 17 Make sure that rotor turns smoothly...
Страница 729: ...Prepared by Overseas Service Department 1st Ed April 2000 Printed in Japan Printing April 2000 736...