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Suzuki Grand Vitara JB416 / JB420. Manual - part 43

1A-121 Engine General Information and Diagnosis:

Wire harness check
1) Disconnect connectors from ECM with ignition switch

turned OFF.

2) Measure resistance between “WHT” and “RED” wire

terminals of electric throttle body assembly connector.

Is resistance infinity?

Go to Step 8.

“RED” wire is shorted to
“WHT” wire.

Wire harness check
1) Turn ON ignition switch.
2) Measure voltage between “C37-40” terminal of ECM

connector and engine ground.

Is voltage 0 V?

Substitute a known-
good ECM and recheck.

“RED” wire is shorted to
power circuit.

Ground circuit check
1) Turn OFF ignition switch.
2) Measure resistance between “GRN” wire terminal of

electric throttle body assembly connector and engine
ground.

Is resistance below 3

Ω

Go to Step 11.

Go to Step 10.

10 Ground circuit check

1) Remove ECM from its bracket with ECM connectors

connected.

2) Check for proper connection of ECM connector at “C37-

41” terminal.

3) Measure resistance between “C37-41” terminal of ECM

connector and engine ground with ignition switch turned
OFF.

Is resistance below 3

Ω

“GRN” wire is open or
high resistance circuit.

Faulty ECM ground
circuit. If circuit is OK,
substitute a known-
good ECM and recheck.

11 Electric throttle body assembly check

1) Check throttle position sensor referring to “Throttle

Position Sensor Performance Check” under “Electric
Throttle Body Assembly On-Vehicle Inspection in
Section 1C”.

Is output voltage within specified value?

Substitute a known-
good ECM and recheck.

Replace electric throttle
body assembly.

Step

Action

Yes

Engine General Information and Diagnosis: 1A-122

DTC P0300 / P0301 / P0302 / P0303 / P0304: Random Misfire Detected / Cylinder 1 / Cylinder 2 /
Cylinder 3 / Cylinder 4 Misfire Detected

S5JB0A1104038

System Description
ECM measures the angle of the crankshaft based on the pulse signal from the CKP sensor and CMP sensor for each
cylinder. If it detects a large change in the angle speed of the crankshaft, it concludes occurrence of a misfire. When
the number of misfire is counted by ECM beyond the DTC detecting condition, it determines the cylinder where the
misfire occurred and output it as DTC.

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure

WARNING

• When performing a road test, select a place where there is no traffic or possibility of a traffic

accident and be very careful during testing to avoid occurrence of an accident.

• Road test should be carried out by 2 persons, a driver and a tester, on a level road.

NOTE
Check to make sure that following conditions are satisfied when using this “DTC Confirmation
Procedure”.
• Intake air temperature at engine start: –10

°C (14 °F) to 80 °C (176 °F)

• Intake air temperature: –10

°C (14 °F) to 70 °C (158 °F)

• Engine coolant temperature: –10

°C (14 °F) to 150 °C (302 °F)

• Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)

1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and print Freeze Frame Data or write them down using scan tool.
3) Clear DTC using scan tool.
4) Drive vehicle under freeze frame data condition as noted for 1 min. or more.
5) Stop vehicle and check DTC and pending DTC.

DTC Troubleshooting

NOTE
Before this trouble shooting is performed, read the precautions for DTC troubleshooting referring to
“Precautions For DTC Troubleshooting”.

DTC detecting condition

Trouble area

DTC P0300:
• Misfire, which causes catalyst to overheat during 200 engine revolutions, is detected

at 2 or more cylinders. (MIL flashes as long as this misfire occurs continuously.)

or
• Misfire, which affects exhaust emission adversely during 1000 engine revolution, is

detected at 2 or more cylinders. (2 driving cycle detection logic)

• Ignition system
• Fuel injector and its circuit
• Fuel pressure
• EGR system
• Abnormal air drawn in
• Engine compression
• Valve lash adjuster
• Valve timing
• Fuel shortage
• Exhaust system
• Fuel of poor quality

DTC P0301, P0302, P0303, P0304:
• Misfire, which causes catalyst to overheat during 200 engine revolutions, is detected

at 1 cylinder. (MIL flashes as long as this misfire occurs continuously.)

or
• Misfire, which affects exhaust emission adversely during 1000 engine revolution, is

detected at 1 cylinder. (2 driving cycle detection logic)

Step

Action

Yes

Was “Engine and Emission Control System Check”
performed?

Go to Step 2.

Go to “Engine and
Emission Control
System Check”.

1A-123 Engine General Information and Diagnosis:

Does fuel level meter indicate “E” level (empty)?

Add fuel and recheck.

Go to Step 3.

Fuel quality check
1) Check that there is fuel of good quality in the fuel tank.

Is it OK?

Go to Step 4.

Clean in fuel system
circuit and change fuel.

Ignition system check
1) Check spark plug and ignition spark of cylinder where

misfire occurs, referring to “Spark Plug Inspection in
Section 1H” and “Ignition Spark Test in Section 1H”.

Are they in good condition?

Go to Step 5.

Faulty ignition coil, wire
harness, spark plug or
other system parts.

Fuel injector circuit check
1) Using sound scope, check each injector operating sound

at engine cranking or idling.

Do all injectors make operating sound?

Go to Step 6.

Check coupler
connection and wire
harness of injector not
making operating sound
and injector itself. If OK,
substitute a known-
good ECM and recheck.

Fuel pressure check
1) Check fuel pressure referring to “Fuel Pressure Check”.

Is check result satisfactory?

Go to Step 7.

Repair or replace fuel
system.

Fuel injector check
1) Check fuel injector(s) referring to “Fuel Injector

Inspection in Section 1G”.

Is check result satisfactory?

Go to Step 8.

Replace defective
injector.

Ignition timing check
1) Check ignition timing referring to “Ignition Timing

Inspection in Section 1H”.

Is check result satisfactory?

Go to Step 9.

Check related sensors.

EGR system check
1) Check EGR system referring to “EGR System Inspection

in Section 1B”.

Is check result satisfactory?

Go to Step 10.

Repair or replace EGR
system.

10 Exhaust system check

1) Check exhaust system for exhaust gas clogged.

Is it OK?

Go to Step 11.

Repair clogged of
exhaust system.

11 Engine mechanical system check

1) Check engine mechanical parts or system which can

cause engine rough idle or poor performance.
• Engine compression (Refer to “Compression Check:

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

• Valve lash (Refer to “Valve Lash (Clearance)

Inspection: For J20 Engine in Section 1D” or “V alve
Lash (Clearance) Inspection: For M16A Engine with
VVT in Section 1D”.)

• Valve timing (Refer to “2nd Timing Chain and Chain

Tensioner Removal and Installation: For J20 Engine in
Section 1D” or “Timing Chain and Chain Tensioner
Removal and Installation: For M16A Engine with VVT
in Section 1D”.)

Are they in good condition?

Check wire harness and
connection of ECM
ground, ignition system
and fuel injector for
intermittent open and
short.

Repair or replace
defective part.

Step

Action

Yes

Engine General Information and Diagnosis: 1A-124

DTC P0327 / P0328: Knock Sensor Circuit Low / High

S5JB0A1104039

Wiring Diagram

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure

1) Connect scan tool to DLC with ignition switch turned OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool.
3) Start engine and run it for 10 sec.
4) Check DTC by using scan tool.

DTC Troubleshooting

NOTE
Before this trouble shooting is performed, read the precautions for DTC troubleshooting referring to
“Precautions For DTC Troubleshooting”.

E23

C37

14
29

54 53

15
30

39 38

14
29

54 53

15
30

39 38

WHT

C37-56

5 V

I5JB0A110046-01

1. Knock sensor
2. ECM

DTC detecting condition

Trouble area

DTC will be set when all of following conditions are detected for
0.5 seconds continuously.
DTC P0327:
• Engine is running
• Voltage of knock sensor is less than 1.23 V
(1 driving cycle detection logic)
DTC P0328:
• Engine is running
• Voltage of knock sensor is 3.91 V or more
(1 driving cycle detection logic)

• Knock sensor circuit (open or short)
• Knock sensor
• ECM

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