Suzuki 2006 SX4, Service Manual

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1A-92 Engine General Information and Diagnosis:
DTC P0420: Catalyst System Efficiency Below Threshold (Bank-1)
S6RW0C1104039
System and Wiring Diagram
System Description
ECM monitors oxygen concentration in the exhaust gas which has passed the warm up three way catalytic converter
by HO2S. When the catalyst is functioning properly, the variation cycle of HO2S output voltage (oxygen concentration)
is slower than that of A/F sensor output signal because the amount of oxygen in the exhaust gas is stored in warm up
three way catalytic converter.
A/F Sensor Description
Refer to “A/F Sensor Description”.
DTC Detecting Condition and Trouble Area
6 CMP sensor check
1) Check CMP sensor and sensor rotor referring to
“Camshaft Position (CMP) Sensor Inspection in Section
1C”.
Are they in good condition?
Substitute a known-
good ECM and recheck. Replace CMP sensor
and/or sensor rotor.
Step Action Yes No
C01-11
C01-38
C01-39
WHT
BRN
1
3
2
4
5 V
BLK/RED
BLU WHT BLU WHT
C01-37
BLK
5
5 V
E01 C01
3 4
18 19
5 6 7 10 11
17 20
47 46 49 50 51
21 22
52
16 25
9
24
14
29
55 57 54 53 59 60 58
2
26 27 28
15
30
56 48
32 31 34 35 36 37 40 42 39 38 44 45 43 41 33
1 12 13
23
8 3 4
18 19
5 6 7 10 11
17 20
47 46 49 50 51
21 22
52
16 25
9
24
14
29
55 57 54 53 59 60 58
2
26 27 28
15
30
56 48
32 31 34 35 36 37 40 42 39 38 44 45 43 41 33
1 12 13
23
8
I7RW01110058-03
1. A/F sensor 3. Warm up three way catalytic converter 5. ECM
2. HO2S 4. Three way catalytic converter
DTC detecting condition Trouble area
Ratio of integrated value of HO2S output variation per integrated value
of A/F sensor output variation is more than specification while vehicle
is running after warmed up.
(2 driving cycle detection logic, monitoring once per driving cycle) • Exhaust gas leak
• Warm up three way catalytic converter
• HO2S
• A/F sensor