Suzuki Grand Vitara JB416 / JB420 / JB419. Manual - part 106

1A-371 Engine General Information and Diagnosis: For Diesel Engine Model

Test 4: MAF sensor

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Test 5: Variable geometry turbocharger control

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Step

Action

Yes

No

1

BREAKAGE OF ELECTRICAL COMPONENTS:
Visual inspection: remove the MAF sensor assembly with 
IAT sensor, the components must not be broken

Is there in good condition?

Go to Step 2.

Replace the MAF 
sensor assembly with 
IAT sensor if necessary.

2

CLOGGING OF THE MAF SENSOR:
Test:
• Check the values for conformity:

– * During the first 5 seconds after starting:

– Coolant temperature: 80 

°C, 176 °F.

– Engine speed: idle speed (800 

± 50 rpm).

– MAF measurement: 490 mg/str 

± 10%.

– EGR valve: between –10% and 0%.

– * After the starting phase:

– Coolant temperature: 80 

°C, 176 °F.

– Engine speed: idle speed (800 

± 50 rpm).

– MAF measurement: 310 mg/str 

± 5%.

– EGR valve: between 10% and 40%.

• Refer to “DTC P0100: Mass or Volume Air Flow Circuit: 

For Diesel Engine Model” for 2.DEF, for the MAF sensor 
checks.

Is there in good condition?

MAF sensor correct.

Replace the MAF 
sensor if necessary.

Step

Action

Yes

No

1

Engine stopped:
Check manually if the variable geometry control rod is 
blocked.

Is the rod blocked?

Replace the 
turbocharger.

Go to Step 2.

2

At idle speed, with boost pressure control solenoid valve 
control:
between of 70% and 85% opening cyclic ratio, disconnect 
the electrical connector of the solenoid valve and check at 
the same time if the rod controlling the variable geometry 
blades moves.

Does the rod move from end stop to end stop?

The turbocharging 
control circuit is 
operating normally.

Go to Step 3.

3

Check the condition of the boost pressure control solenoid 
valve connectors (corrosion, bent pins, etc.). Measure the 
resistance of the solenoid valve referring to “Boost Pressure 
Control Solenoid Valve Inspection: For Diesel Engine Model 
in Section 1C”.

Is the solenoid valve in order?

Go to Step 4.

Replace the boost 
pressure control 
solenoid valve.

4

Check the electric harness of boost pressure control 
solenoid valve

Is there in good condition?

Go to step 5.

Repair as necessary.

Engine General Information and Diagnosis: For Diesel Engine Model 1A-372

Test 6: Rotating part of a turbocharger

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5

Reconnect the electrical connector of the boost pressure 
control solenoid valve.
On the control diaphragm of the variable geometry blades, 
disconnect the pipe coming from the solenoid valve. 
Connect a pressure gauge in place of the diaphragm. 
Engine at idling speed.

Is the vacuum pressure > 750 mbar?

Replace the 
turbocharger.

Go to Step 6.

6

Measure the vacuum pressure upstream of the boost 
pressure control solenoid valve.

Is the vacuum pressure > 750 mbar?

Replace the boost 
pressure control 
solenoid valve.

Check the vacuum 
circuit and repeat the 
test from the vacuum 
pressure check.

Step

Action

Yes

No

Step

Action

Yes

No

1

With the engine cold and stopped, remove the air inlet duct 
from the turbocharger, check manually if the compressor 
and turbine shaft turns.

Does the shaft turn?

Go to Step 2.

Replace the 
turbocharger. Seizing of 
the turbocharger could 
be caused by poor 
lubrication of the 
bearings. Check the 
lubrication circuit for any 
blockage and check the 
engine oil pressure. 
Perform an oil change 
and change the oil filter.

2

Perform a visual inspection of the condition of the 
compressor and turbine wheels. ([A]: Deformed, twisted 
blade (“soft” foreign body), [B]: Broken blades (“hard” foreign 
body))

Are the compressor and turbine wheels in good condition?

Go to Step 3.

• Replace the 

turbocharger.

• Replace the duct 

connected to the 
damaged wheel.

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1A-373 Engine General Information and Diagnosis: For Diesel Engine Model

Test 7: Exhaust gas recirculation valve

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3

Manually check the axial play of the wheels. ([A]: Axial play, 
[B]: Radial play)

The significant axial play is approximately 2 mm (0.080 in.). 
Does the turbo have too much play in the shaft?

Replace the 
turbocharger. If the 
rotating part is broken:
change the engine oil 
and the oil filter.
clean the intercooler 
and the air circuit ducts.

The rotating part is in 
order.

Step

Action

Yes

No

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Step

Action

Yes

No

1

VALVE POSITION FAULT FINDING:
Or detection of a leak in the exhaust gas recirculation valve
Clear the faults.
Use “Initialize EGR valve data” on SUZUKI scan tool 
command to try to reinitialise the operating values of the 
EGR valve.
Switch OFF the ignition and wait 40 seconds.
Switch the ignition back on and check for faults.
If the fault is still present:
• Switch OFF the vehicle ignition.
• Disconnect the connector of the EGR valve.
• Remove the EGR valve referring to “EGR Valve Removal 

and Installation: For F9Q Engine in Section 1D” and 
reconnect it after having removed it.

• Check that no particles are blocking the movement of the 

EGR valve flap.

• Check that the EGR valve is not stuck or jammed in one 

position.

• Switch ON the ignition again.
• Check the movement of the valve with displaying “EGR 

position sensor” on Data List of SUZUKI scan tool (0 to 
2.5 mm travel for an opening cyclic ratio of 40% and when 
fully open, ~ 5 mm, for an opening cyclic ratio of 95%).

• Check that the EGR valve flap closes completely.

Is there in good condition?

Go to Step 2.

Replace the EGR valve 
referring to “EGR Valve 
Removal and 
Installation: For F9Q 
Engine in Section 1D”.

2

EGR VALVE BUSHING FAULT FINDING:
Remove the EGR valve referring to “EGR Valve Removal 
and Installation: For F9Q Engine in Section 1D” the EGR 
valve should not contain a cluster of soot between the base 
and the valve.
Clean the EGR valve sleeve if necessary.

Is there in good condition?

Go to Step 3.

Replace the EGR valve 
referring to “EGR Valve 
Removal and 
Installation: For F9Q 
Engine in Section 1D”.

Engine General Information and Diagnosis: For Diesel Engine Model 1A-374

Test 8: Injector malfunction

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WARNING

!

 

When servicing fuel system, be sure to observe WARNING in “Precautions on Fuel System Service: 
For Diesel Engine Model in Section 1G” to reduce the risk of fire and personal injury.

 

3

1) Use “Initialize EGR valve data” on SUZUKI scan tool 

command to try to reinitialise the operating values of the 
EGR valve.

2) Check the air circuit referring to “Test 3: Checking the 

turbocharged air inlet circuit: For Diesel Engine Model”.

3) Check the MAF sensor referring to “Test 4: MAF sensor: 

For Diesel Engine Model”.

Is there in good condition?

Go to Step 4.

Repair as necessary.

4

Confirmation of the fault finding:
• Start the vehicle.
• Leave the engine at idling speed for 1 min.
• Accelerate very slowly up to 1500 rpm for 2 mins until the 

exhaust gas recirculation function becomes active.

• Carry out a vehicle test at low speed, without accelerating 

heavily, then normally.

• Check for faults using SUZUKI scan tool.

Does customer complaint or the faults recur?

Substitute a known-
good ECM and recheck.

Exhaust gas 
recirculation valve 
correct.

Step

Action

Yes

No

Step

Action

Yes

No

1

CHECK THE FUEL REGULATION BALANCE, INJECTOR 
BY INJECTOR
• With the engine at idle speed, coolant temperature > 80 

°C, 176 °F, display the each injector fuel flow correction 
values “Cyl # FF Correction” on Data List of SUZUKI scan 
tool.

The normal value for fuel flow correction for an injector is 

± 

1.0 mm

3

/stroke.

This tolerance may increase with time, but indicates an 
injector/cylinder fault if it exceeds 

± 5.0 mm

3

/ stroke.

Do one of these values exceed 

±

 5.0 mm

3

/stroke?

Go to Step 2.

Go to Step 4.