Dtc P0420: Catalyst System Efficiency Below Threshold (Bank-1) - Suzuki 2006 SX4 Service Manual

1A-92 Engine General Information and Diagnosis:
Step
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?

DTC P0420: Catalyst System Efficiency Below Threshold (Bank-1)

System and Wiring Diagram
BLU WHT
1
3
15 14 13 12 11
30 29 28 27 26
44
45 43 42 41
60 59 58 57 56
1. A/F sensor
2. HO2S
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
DTC detecting condition
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)
Action
WHT BLU
2
E01
10 9 8 7 6 5 4 3
25 24 23 22 21 20 19 18
40 39 38 37 36 35 34 33
55 54 53 52 51 50 49 48
3. Warm up three way catalytic converter
4. Three way catalytic converter
Substitute a known-
good ECM and recheck.
WHT
BLK
BLK/RED
BRN
4
2 1 15 14 13 12 11
17 16 30 29 28 27 26
44
32 31 45 43 42 41
47 46 60 59 58 57 56
• Exhaust gas leak
• Warm up three way catalytic converter
• HO2S
• A/F sensor
Yes
Replace CMP sensor
and/or sensor rotor.
5
5 V
C01-38
C01-37
C01-39
5 V
C01-11
C01
10 9 8 7 6 5 4 3
25 24 23 22 21 20 19 18
40 39 38 37 36 35 34 33
55 54 53 52 51 50 49 48
5. ECM
Trouble area
No
S6RW0C1104039
2 1
17 16
32 31
47 46
I7RW01110058-03