Suzuki Grand Vitara 2011 Manual page 131

Condition
Excessive nitrogen
oxides (NOx) emission
Engine General Information and Diagnosis: For Petrol Engine Model 1A-62
Possible cause
Improper ignition timing
Lead contamination of catalytic
converter
Faulty EGR system
Fuel pressure out of specification
Closed loop system (A/F feedback
compensation) fails (Faulty TP sensor,
Poor performance of ECT sensor or
MAF sensor)
Faulty electric throttle body assembly
Faulty accelerator pedal position (APP)
sensor assembly
Faulty injector(s)
Faulty ECM
Camshaft position control (VVT) system
out of order (for M16 engine)
Correction / Reference Item
"Ignition Timing Inspection: For Petrol Engine
Model in Section 1H"
Check for absence of filler neck restrictor.
"EGR System Inspection: For Petrol Engine
Model in Section 1B"
"Fuel Pressure Check: For Petrol Engine
Model"
"Electric Throttle Body Assembly On-Vehicle
Inspection: For Petrol Engine Model in Section
1C", "Engine Coolant Temperature (ECT)
Sensor Inspection: For Petrol Engine Model in
Section 1C" or "Mass Air Flow (MAF) and
Intake Air Temperature (IAT) Sensor
Inspection: For Petrol Engine Model in Section
1C"
"Electric Throttle Body Assembly On-Vehicle
Inspection: For Petrol Engine Model in Section
1C"
"Accelerator Pedal Position (APP) Sensor
Assembly Inspection: For Petrol Engine Model
in Section 1C"
"Fuel Injector Circuit Check: For Petrol Engine
Model"
"Oil Control Valve Inspection: For M16A
Engine with VVT in Section 1D"