Suzuki Liana RH413 Service Manual page 117

DTC P0171 / P0172: Fuel System Too Lean / Rich
Wiring Diagram
2
3
2
1. Injector
2. HO2S-1
3. WU-TWC (Warm up-three way catalytic convector)
4. Sensed information
5. ECM
DTC Detecting Condition and Possible Cause
DTC detecting condition
When one of the following conditions is met while engine
running under closed loop condition.
• Air/fuel ratio too lean
(Total fuel trim (short and long terms added) is more than
30%)
• Air/fuel ratio too rich
(Total fuel trim is less than – 30%)
*2 driving cycle detection logic, continuous monitoring
4
5
1
+B
1
[a]: Signal to decrease amount of fuel injection
[b]: Signal to increase amount of fuel injection
[c]: High voltage
[d]: Low voltage
[e]: A/F mixture becomes richer
Engine General Information and Diagnosis:
[a]
[b]
5
1
[e] [g]
[f] [h]
C41-9
BLU/YEL
BLU/WHT C41-21
BLU/RED C41-31
BLU/GRN C41-8
C41-1
BLK/ORN
C41-3
BLK
WHT C41-13
ORN C41-10
Possible cause
• Vacuum leaks (air drawn in)
• Exhaust gas leakage
• Heated oxygen sensor-1 circuit malfunction
• Fuel pressure out of specification
• Fuel injector malfunction (clogged or leakage)
• MAP sensor poor performance
• ECT sensor poor performance
• IAT sensor poor performance
• TP sensor poor performance
• EVAP control system malfunction
• PCV valve malfunction
1A-66
S3RH0A1104035
[c]
[d]
2
ECM
I2RH0B110037-01
[f]: A/F mixture becomes leaner
[g]: Oxygen concentration decreases
[h]: Oxygen concentration increases