Dtc P0171 Fuel System Too Lean; Dtc P0172 Fuel System Too Rich - Suzuki Jimny Service Manual

6-68 ENGINE GENERAL INFORMATION AND DIAGNOSIS

DTC P0171 Fuel System Too Lean

DTC P0172 Fuel System Too Rich

CIRCUIT DESCRIPTION
[a] : Signal to decrease amount of fuel injection
[b] : Signal to increase amount of fuel injection
[c] : A/F mixture becomes leaner
(Oxygen concentration increases)
DTC DETECTING CONDITION
• When following condition occurs while engine running
under closed loop condition.
– Air / fuel ratio too lean
(Total fuel trim (short and long terms added) is more
than 30%)
or
– Air / fuel ratio too rich
(Total fuel trim is less than –30%)
✱ ✱ ✱ ✱ 2 driving cycle detection logic, continuous monitoring.
[d] : A/F mixture becomes richer
(Oxygen concentration decreases)
[e] : High voltage
[f] : Low voltage
• 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.
1. Injector
2. Heated oxygen sensor-1 (HO2S-1)
POSSIBLE CAUSE