Suzuki Grand Vitara JB416 / JB420 / JB419. Manual - part 27

1A-55 Engine General Information and Diagnosis: For Petrol Engine Model

Engine overheating

Inoperative thermostat

“Thermostat Inspection: For Petrol Engine 
Model in Section 1F”

Poor water pump performance

“Water Pump Inspection: For Petrol Engine 
Model in Section 1F”

Clogged or leaky radiator

“Radiator On-Vehicle Inspection and Cleaning: 
For Petrol Engine Model in Section 1F”

Improper engine oil grade

“Engine Oil and Filter Change (Petrol Engine 
Model) in Section 0B”

Clogged oil filter or oil strainer

“Oil Pressure Check: For J20 Engine in 
Section 1E” or “Oil Pressure Check: For M16A 
Engine with VVT in Section 1E”

Poor oil pump performance

“Oil Pressure Check: For J20 Engine in 
Section 1E” or “Oil Pressure Check: For M16A 
Engine with VVT in Section 1E”

Faulty radiator cooling fan control 
system

“Radiator Cooling Fan Low Speed Control 
System Check: For Petrol Engine Model” or 
“Radiator Cooling Fan High Speed Control 
System Check: For Petrol Engine Model”

Dragging brakes

Condition “Dragging brakes” in “Brakes 
Symptom Diagnosis in Section 4A”

Slipping clutch (for M/T model)

Condition “Slipping clutch” in “Clutch 
(Hydraulic Type) Symptom Diagnosis in 
Section 5C”

Blown cylinder head gasket

“Cylinder Head Inspection: For J20 Engine in 
Section 1D” or “Cylinder Head Inspection: For 
M16A Engine with VVT in Section 1D”

Air mixed in cooling system

Condition

Possible cause

Correction / Reference Item

Engine General Information and Diagnosis: For Petrol Engine Model 1A-56

Poor gasoline mileage

Leaks or loose connection of high-
tension cord (for M16 engine)

“High-Tension Cord Removal and Installation 
(For M16 Engine): For Petrol Engine Model in 
Section 1H”

Faulty spark plug (improper gap, heavy 
deposits and burned electrodes, etc.)

“Spark Plug Inspection: For Petrol Engine 
Model in Section 1H”

Malfunctioning EGR valve

“EGR Valve Inspection: For Petrol Engine 
Model in Section 1B”

High idle speed

Condition “Improper engine idling or engine 
fails to idle”

Poor performance of ECT sensor or 
MAF sensor

“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”

Faulty electric throttle body assembly

“Electric Throttle Body Assembly On-Vehicle 
Inspection: For Petrol Engine Model in Section 
1C”

Faulty accelerator pedal position (APP) 
sensor assembly

“Accelerator Pedal Position (APP) Sensor 
Assembly Inspection: For Petrol Engine Model 
in Section 1C”

Faulty fuel injector(s)

“Fuel Injector Circuit Check: For Petrol Engine 
Model”

Faulty ECM
Low compression

“Compression Check: For J20 Engine in 
Section 1D” or “Compression Check: For 
M16A Engine with VVT in Section 1D”

Poor valve seating

“Valves and Valve Guides Inspection: For J20 
Engine in Section 1D” or “Valves and Valve 
Guides Inspection: For M16A Engine with VVT 
in Section 1D”

Dragging brakes

Condition “Dragging brakes” in “Brakes 
Symptom Diagnosis in Section 4A”

Slipping clutch (for M/T model)

Condition “Slipping clutch” in “Clutch 
(Hydraulic Type) Symptom Diagnosis in 
Section 5C”

Thermostat out of order

“Thermostat Inspection: For Petrol Engine 
Model in Section 1F”

Improper tire pressure

“Tires Description in Section 2D”

Camshaft position control (VVT) system 
out of order (for M16 engine)

“Oil Control Valve Inspection: For M16A 
Engine with VVT in Section 1D”

Excessive engine oil 
consumption – Oil 
leakage

Blown cylinder head gasket

“Cylinder Head Inspection: For J20 Engine in 
Section 1D” or “Cylinder Head Inspection: For 
M16A Engine with VVT in Section 1D”

Leaky camshaft oil seals

“Camshaft, Tappet and Shim Inspection: For 
J20 Engine in Section 1D” or “Camshaft, 
Tappet and Shim Inspection: For M16A Engine 
with VVT in Section 1D”

Condition

Possible cause

Correction / Reference Item

1A-57 Engine General Information and Diagnosis: For Petrol Engine Model

Excessive engine oil 
consumption – Oil 
entering combustion 
chamber

Sticky piston ring

“Pistons, Piston Rings, Connecting Rods and 
Cylinders Inspection and Cleaning: For J20 
Engine in Section 1D” or “Cylinders, Pistons 
and Piston Rings Inspection: For M16A Engine 
with VVT in Section 1D”

Worn piston and cylinder

“Pistons, Piston Rings, Connecting Rods and 
Cylinders Inspection and Cleaning: For J20 
Engine in Section 1D” or “Cylinders, Pistons 
and Piston Rings Inspection: For M16A Engine 
with VVT in Section 1D”

Worn piston ring groove and ring

“Pistons, Piston Rings, Connecting Rods and 
Cylinders Inspection and Cleaning: For J20 
Engine in Section 1D” or “Cylinders, Pistons 
and Piston Rings Inspection: For M16A Engine 
with VVT in Section 1D”

Improper location of piston ring gap

“Pistons, Piston Rings, Connecting Rods and 
Cylinders Disassembly and Assembly: For J20 
Engine in Section 1D” or “Pistons, Piston 
Rings, Connecting Rods and Cylinders 
Disassembly and Assembly: For M16A Engine 
with VVT in Section 1D”

Worn or damaged valve stem seal

“Valves and Valve Guides Inspection: For J20 
Engine in Section 1D” or “Valves and Valve 
Guides Inspection: For M16A Engine with VVT 
in Section 1D”

Worn valve stem

“Valves and Valve Guides Inspection: For J20 
Engine in Section 1D” or “Valves and Valve 
Guides Inspection: For M16A Engine with VVT 
in Section 1D”

Engine hesitates – 
Momentary lack of 
response as accelerator 
is depressed. Can occur 
at all vehicle speeds. 
Usually most severe when 
first trying to make 
vehicle move, as from a 
stop sign

Spark plug faulty or plug gap out of 
adjustment

“Spark Plug Inspection: For Petrol Engine 
Model in Section 1H”

Leaky high-tension cord (for M16 
engine)

“High-Tension Cord Inspection (For M16 
Engine): For Petrol Engine Model in Section 
1H”

Fuel pressure out of specification

“Fuel Pressure Check: For Petrol Engine 
Model”

Malfunctioning EGR valve

“EGR Valve Inspection: For Petrol Engine 
Model in Section 1B”

Poor performance of ECT sensor or 
MAF sensor

“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”

Faulty electric throttle body assembly

“Electric Throttle Body Assembly On-Vehicle 
Inspection: For Petrol Engine Model in Section 
1C”

Faulty accelerator pedal position (APP) 
sensor assembly

“Accelerator Pedal Position (APP) Sensor 
Assembly Inspection: For Petrol Engine Model 
in Section 1C”

Faulty fuel injector

“Fuel Injector Circuit Check: For Petrol Engine 
Model”

Faulty ECM
Engine overheating

Condition “Engine overheating”

Low compression

“Compression Check: For J20 Engine in 
Section 1D” or “Compression Check: For 
M16A Engine with VVT in Section 1D”

Camshaft position control (VVT) system 
out of order (for M16 engine)

“Oil Control Valve Inspection: For M16A 
Engine with VVT in Section 1D”

Condition

Possible cause

Correction / Reference Item

Engine General Information and Diagnosis: For Petrol Engine Model 1A-58

Surge – Engine power 
variation under steady 
throttle or cruise. Feels 
like vehicle speeds up 
and down with no change 
in accelerator pedal

Leaky or loosely connected high-tension 
cord (for M16 engine)

“High-Tension Cord Removal and Installation 
(For M16 Engine): For Petrol Engine Model in 
Section 1H”

Faulty spark plug (excess carbon 
deposits, improper gap, burned 
electrodes, etc.)

“Spark Plug Inspection: For Petrol Engine 
Model in Section 1H”

Variable fuel pressure

“Fuel Pressure Check: For Petrol Engine 
Model”

Kinky or damaged fuel hose and lines
Faulty fuel pump (clogged fuel filter)
Malfunctioning EGR valve

“EGR Valve Inspection: For Petrol Engine 
Model in Section 1B”

Poor performance of MAF sensor

“Mass Air Flow (MAF) and Intake Air 
Temperature (IAT) Sensor Inspection: For 
Petrol Engine Model in Section 1C”

Faulty fuel injector

“Fuel Injector Circuit Check: For Petrol Engine 
Model”

Faulty ECM
Faulty electric throttle body assembly

“Electric Throttle Body Assembly On-Vehicle 
Inspection: For Petrol Engine Model in Section 
1C”

Faulty accelerator pedal position (APP) 
sensor assembly

“Accelerator Pedal Position (APP) Sensor 
Assembly Inspection: For Petrol Engine Model 
in Section 1C”

Excessive detonation – 
Engine makes 
continuously sharp 
metallic knocks that 
change with throttle 
opening. Sounds like pop 
corn popping

Faulty spark plug

“Spark Plug Inspection: For Petrol Engine 
Model in Section 1H”

Loose connection of high-tension cord 
(for M16 engine)

“High-Tension Cord Removal and Installation 
(For M16 Engine): For Petrol Engine Model in 
Section 1H”

Engine overheating

Condition “Engine overheating”

Clogged fuel filter (faulty fuel pump) or 
fuel lines

“Fuel Pressure Check: For Petrol Engine 
Model” or “Fuel Pump and Its Circuit Check: 
For Petrol Engine Model”

Air drawn in through intake manifold or 
throttle body gasket
Malfunctioning EGR valve

“EGR Valve Inspection: For Petrol Engine 
Model in Section 1B”

Poor performance of knock sensor, ECT 
sensor or MAF sensor

“DTC P0327 / P0328: Knock Sensor Circuit 
Low / High: For Petrol Engine Model”, “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”

Faulty fuel injector(s)

“Fuel Injector Circuit Check: For Petrol Engine 
Model”

Faulty ECM
Excessive combustion chamber 
deposits

“Pistons, Piston Rings, Connecting Rods and 
Cylinders Inspection and Cleaning: For J20 
Engine in Section 1D” or “Cylinders, Pistons 
and Piston Rings Inspection: For M16A Engine 
with VVT in Section 1D” and/or “Piston Pins 
and Connecting Rods Inspection: For M16A 
Engine with VVT in Section 1D”

Camshaft position control (VVT) system 
out of order (for M16 engine)

“Oil Control Valve Inspection: For M16A 
Engine with VVT in Section 1D”

Condition

Possible cause

Correction / Reference Item