Suzuki Grand Vitara JB416 / JB420. Manual - part 13

1A-1 Engine General Information and Diagnosis: 

Engine

Engine General Information and Diagnosis

Precautions

Precautions on Engine Service

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CAUTION

!

 

The following information on engine service 
should be noted carefully, as it is important in 
preventing damage, and in contributing to 
reliable engine performance.

 

• When raising or supporting engine for any reason, do 

not use a jack under oil pan. Due to small clearance 
between oil pan and oil pump strainer, jacking against 
oil pan may cause it to be bent against strainer, 
resulting in damaged oil pick-up unit.

• It should be kept in mind, while working on engine, 

that 12-volt electrical system is capable of violent and 
damaging short circuits.
When performing any work where electrical terminals 
can be grounded, ground cable of the battery should 
be disconnected at battery.

• Any time the air cleaner, throttle body or intake 

manifold is removed, the intake opening should be 
covered. This will protect against accidental entrance 
of foreign material which could follow intake passage 
into cylinder and cause extensive damage when 
engine is started.

Precautions in Diagnosing Trouble

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• Don’t disconnect couplers from ECM, battery cable 

from battery, ECM ground wire harness from engine 
or main fuse before confirming diagnostic information 
(DTC, freeze frame data, etc.) stored in ECM memory. 
Such disconnection will erase memorized information 
in ECM memory.

• Diagnostic information stored in ECM memory can be 

cleared as well as checked by using SUZUKI scan 
tool or OBD generic scan tool (Vehicle without 
diagnosis connector). Before using scan tool, read its 
Operator’s (Instruction) Manual carefully to have good 
understanding as to what functions are available and 
how to use it.
It is indistinguishable which module turns on MIL 
because not only ECM but also TCM (for A/T model) 
turns on MIL (For details of on-board diagnostic 
system for A/T model, refer to “On-Board Diagnostic 
System Description in Section 5A”. Therefore, check 
both ECM and TCM (for A/T model) for DTC when 
MIL lights on.
When checking ECM for DTC, keep in mind that DTC 
is displayed on the scan tool as follows depending on 
the scan tool used.

– SUZUKI scan tool displays DTC detected by ECM.
– OBD generic scan tool displays DTC detected by 

each of ECM and TCM (for A/T model) 
simultaneously.

• Priorities for diagnosing troubles

If two or more DTCs are stored, proceed to the DTC 
flow which has been detected earliest in the order and 
follow the instruction in that flow.
If no instructions are given, troubleshoot DTCs 
according to the following priorities.
a. DTCs other than DTC P0171 / P0172 (Fuel 

system too lean / too rich), DTC P0300 / P0301 / 
P0302 / P0303 / P0304 (Misfire detected) and 
DTC P0401 / P0402 (EGR flow malfunction)

b. DTC P0171 / P0172 (Fuel system too lean / too 

rich) and DTC P0401 / P0402 (EGR flow 
malfunction)

c. DTC P0300 / P0301 / P0302 / P0303 / P0304 

(Misfire detected)

• Be sure to read “Precautions for Electrical Circuit 

Service in Section 00” before inspection and observe 
what is written there.

• ECM replacement:

When substituting a known-good ECM, check for the 
following conditions. Neglecting this check may cause 
damage to a known-good ECM.
– Resistance value of all relays, actuators is as 

specified respectively.

– MAP sensor, electric load current sensor (for J20 

engine), A/C refrigerant pressure sensor (if 
equipped with A/C), accelerator pedal position 
(APP) sensor, TP sensor and CO adjust resistor (if 
not equipped with A/F sensor) are in good condition 
and none of power circuits of these sensors is 
shorted to ground.

• Communication of ECM, BCM, combination meter, 

keyless start control module (if equipped) ABS 
hydraulic unit / control module assembly, 4WD control 
module (for J20 engine) and TCM (for A/T model), is 
established by CAN (Controller Area Network). (For 
more detail of CAN communication for ECM, refer to 
“CAN Communication System Description”). 
Therefore, handle CAN communication line with care 
referring to “Precaution for CAN Communication 
System in Section 00”.

• Immobilizer transponder code registration after 

replacing ECM
When ECM is replaced with new one or with another 
one, make sure to register immobilizer transponder 
code to ECM correctly according to “Procedure after 
ECM Replacement in Section 10C”.

Engine General Information and Diagnosis:  1A-2

Precautions For DTC Troubleshooting

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• Before performed trouble shooting, be sure to read 

the “Precautions of ECM Circuit Inspection”.

• When measuring circuit voltage, resistance and/or 

pulse signal at ECM connector, connect the special 
tool to ECM and/or the ECM connectors referring to 
“Inspection of ECM and Its Circuits”.

• Upon completion of inspection and repair work, 

perform “DTC Confirmation Procedure” and confirm 
that the trouble has been corrected.

Precautions of ECM Circuit Inspection

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• ECM connectors are waterproofed. Each terminal of 

the ECM connectors is sealed up with the grommet. 
Therefore, when measuring circuit voltage, resistance 
and/or pulse signal at ECM connector, do not insert 
the tester’s probe into the sealed terminal at the 
harness side. When measuring circuit voltage, 
resistance and/or pulse signal at ECM connector, 
connect the special tool to the ECM connectors. And, 
insert the tester’s probe into the special tool’s 
connectors at the harness side, and then measure 
voltage, resistance and/or pulse signal. Or, ECM and 
its circuits may be damaged by water.

• Wire colors of the special tool’s connectors are 

different from the ones of the ECM connectors. 
However, the circuit arrangement of the special tool’s 
connectors is same as the one of the ECM 
connectors. Therefore, measure circuit voltage and 
resistance by identifying the terminal location subject 
to the measurement.

Precautions of Electric Throttle Body System 
Calibration

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After performing one of works described below, it is 
necessary to re-register the completely closed throttle 
valve reference position stored in memory of ECM. (For 
detailed information, refer to “Description of Electric 
Throttle Body System Calibration”.) For the procedure to 
register such data in ECM, refer to “Electric Throttle 
Body System Calibration in Section 1C”.
• To shut off backup power of ECM for such purposes of 

battery replacement or “DOME” fuse removal

• To erase DTCs P0122, P0123, P0222, P0223, P2101, 

P2102, P2103, P2111, P2119 and/or P2135

• To replace ECM
• To replace throttle body and/or accelerator pedal 

position (APP) sensor assembly

General Description

Statement on Cleanliness and Care

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An automobile engine is a combination of many 
machined, honed, polished and lapped surfaces with 
tolerances that are measured in the thousands of an 
millimeter (ten thousands of an inch).
Accordingly, when any internal engine parts are 
serviced, care and cleanliness are important.
It should be understood that proper cleaning and 
protection of machined surfaces and friction areas is part 
of the repair procedure. This is considered standard 
shop practice even if not specifically stated.
• A liberal coating of engine oil should be applied to 

friction areas during assembly to protect and lubricate 
the surfaces on initial operation.

• Whenever valve train components, pistons, piston 

rings, connecting rods, rod bearings, and crankshaft 
journal bearings are removed for service, they should 
be retained in order.
At the time of installation, they should be installed in 
the same locations and with the same mating 
surfaces as when removed.

• Battery cables should be disconnected before any 

major work is performed on the engine.
Failure to disconnect cables may result in damage to 
wire harness or other electrical parts.

• The four cylinders of the engine are identified by 

numbers; No.1 (1), No.2 (2), No.3 (3) and No.4 (4) 
counted from crankshaft pulley side to flywheel side.

[A]: J20 engine
[B]: M16 engine

1

1

2

2

3

3

4

4

[A]

[B]

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1A-3 Engine General Information and Diagnosis: 

Engine Diagnosis General Description

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This vehicle is equipped with an engine and emission 
control system which are under control of ECM.
The engine and emission control system in this vehicle 
are controlled by ECM. ECM has an On-Board 
Diagnostic system which detects a malfunction in this 
system and abnormality of those parts that influence the 
engine exhaust emission. When diagnosing engine 
troubles, be sure to have full understanding of the outline 
of “On-Board Diagnostic System Description” and each 
item in “Precautions in Diagnosing Trouble” and execute 
diagnosis according to “Engine and Emission Control 
System Check”.
There is a close relationship between the engine 
mechanical, engine cooling system, ignition system, 
exhaust system, etc. and the engine and emission 
control system in their structure and operation. In case of 
an engine trouble, even when the malfunction indicator 
lamp (MIL) doesn’t turn ON, it should be diagnosed 
according to “Engine and Emission Control System 
Check”.

On-Board Diagnostic System Description

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Vehicle not Equipped with Diagnosis Connector
ECM in this vehicle has the following functions.
• When the ignition switch is turned ON with the engine 

at a stop, malfunction indicator lamp (MIL) (1) turns 
ON to check the circuit of the malfunction indicator 
lamp (1).

• When ECM detects a malfunction which gives an 

adverse effect to vehicle emission while the engine is 
running, it makes the malfunction indicator lamp (1) in 
the meter cluster of the instrument panel turn ON or 
flash (flashing only when detecting a misfire which 
can cause damage to the catalyst) and stores the 
malfunction area in its memory.
(If it detects that continuously 3 driving cycles are 
normal after detecting a malfunction, however, it 
makes MIL (1) turn OFF although DTC stored in its 
memory will remain.)

• As a condition for detecting a malfunction in some 

areas in the system being monitored by ECM and 
turning ON the malfunction indicator lamp (1) due to 
that malfunction, 2 driving cycle detection logic is 
adopted to prevent erroneous detection.

• When a malfunction is detected, engine and driving 

conditions then are stored in ECM memory as freeze 
frame data. (For the details, refer to description on 
“Freeze Frame Data (Vehicle Not Equipped with 
Diagnosis Connector): ”.)

• It is possible to communicate by using not only 

SUZUKI scan tool (2) but also OBD generic scan tool. 
(Diagnostic information can be accessed by using a 
scan tool.)

Vehicle Equipped with Diagnosis Connector
ECM diagnosis troubles which may occur in the area 
including the following parts when the ignition switch is 
ON and the engine is running, and indicates the result by 
turning on or flashing malfunction indicator lamp (1).
• A/F sensor (if equipped)
• Heated oxygen sensor (if equipped)
• ECT sensor
• TP sensor
• MAF sensor
• IAT sensor
• MAP sensor
• CMP sensor
• CKP sensor
• Knock sensor
• Wheel speed sensor
• CPU (Central Processing Unit) of ECM
• APP sensor
• Oil control valve (for M16 engine)
• Radiator cooling fan relay
ECM and malfunction indicator lamp (1) operate as 
follows.
• Malfunction indicator lamp (1) lights when the ignition 

switch is turned ON (but the engine at stop) with the 
diagnosis switch terminal ungrounded regardless of 
the condition of Engine and Emission control system. 
This is only to check the malfunction indicator lamp (1) 
in the combination meter and its circuit.

3. DLC

1

2

3

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Engine General Information and Diagnosis:  1A-4

• If the above areas of Engine and Emission control 

system is free from any trouble after the engine start 
(while engine is running), malfunction indicator lamp 
(1) turns OFF.

• When ECM detects a trouble which has occurred in 

the above areas, it makes malfunction indicator lamp 
(1) turn ON while the engine is running to warn the 
driver of such occurrence of trouble and at the same 
time it stores the trouble area in ECM back-up 
memory. (The memory is kept as it is even if the 
trouble was only temporary and disappeared 
immediately. And it is not erased unless the power to 
ECM is shut off for specified time or it is cleared by 
SUZUKI scan tool (2).)
In addition, DTC can be read by not only using 
SUZUKI scan tool but also displayed on odometer (5) 
of the combination meter. (i.e. when diagnosis switch 
terminal (3) is grounded with a service wire (4) and 
ignition switch is turned ON.) For further detail of the 
checking procedure, refer to “DTC Check”.

Warm-Up Cycle
A warm-up cycle means sufficient vehicle operation such 
that the coolant temperature has risen by at least 22 

°C 

(40 

°F) from engine starting and reaches a minimum 

temperature of 70 

°C (160 °F).

Driving Cycle
A “Driving Cycle” consists of engine startup and engine 
shutoff.

2 Driving Cycle Detection Logic
The malfunction detected in the first driving cycle is 
stored in ECM memory (in the form of pending DTC) but 
the malfunction indicator lamp does not light at this time. 
It lights up at the second detection of same malfunction 
also in the next driving cycle.

Pending DTC
Pending DTC means a DTC detected and stored 
temporarily at 1 driving cycle of the DTC which is 
detected in the 2 driving cycle detection logic.

Freeze Frame Data (Vehicle Not Equipped with 
Diagnosis Connector)
ECM stores the engine and driving conditions (in the 
form of data as shown in the figure) at the moment of the 
detection of a malfunction in its memory. This data is 
called “Freeze frame data”.
Therefore, it is possible to know engine and driving 
conditions (e.g., whether the engine was warm or not, 
where the vehicle was running or stopped, where air/fuel 
mixture was lean or rich) when a malfunction was 
detected by checking the freeze frame data. Also, ECM 
has a function to store each freeze frame data for three 
different malfunctions in the order as each malfunction is 
detected. Utilizing this function, it is possible to know the 
order of malfunctions that have been detected. Its use is 
helpful when rechecking or diagnosing a trouble.

6. Diagnosis connector

1

5

6

2

3

4

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[A]: 1st or 2nd in parentheses here represents which position in the order 

the malfunction is detected.

[A]

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