Suzuki Grand Vitara JB627. Service 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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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 could possibly be 
grounded, ground cable of the battery should be 
disconnected at battery.

• Any time the air cleaner, air intake pipe, 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.

• When disconnecting couplers, don’t pull wire harness 

but make sure to hold coupler itself. With lock type 
coupler, be sure to unlock before disconnection. 
Attempt to disconnect coupler without unlocking may 
result in damage to coupler. When connecting lock 
type coupler, insert it till clicking sound is heard and 
connect it securely.

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. 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 (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 (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 (A/T model) simultaneously.

• Priorities for diagnosing troubles

If two or more diagnostic trouble codes (DTCs) are 
stored, proceed to the flow of the DTC which has 
detected earliest in the order and follow the instruction 
in that table.
If no instructions are given, troubleshoot diagnostic 
trouble codes according to the following priorities.
a. Diagnostic trouble codes (DTCs) other than DTC 

P0171 / P0172 / P0174 / P0175 (Fuel system too 
lean/too rich), DTC P0300 / P0301 / P0302 / 
P0303 / P0304 / P0305 / P0306 (Misfire detected) 
and DTC P0401 / P0402 (EGR flow malfunction)

b. DTC P0171 / P0172 / P0174 / P0175 (Fuel 

system too lean/too rich) and DTC P0401 / P0402 
(EGR flow malfunction)

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

P0305 / P0306 (Misfire detected)

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Engine General Information and Diagnosis:  1A-2

• Be sure to read “Precaution for CAN Communication 

System 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 known good ECM.
– Resistance value of all relays, actuators is as 

specified respectively.

– MAF sensor MAP sensor, TP sensor and A/C 

refrigerant pressure 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 or 
ESP

® control module, 4WD control module (if 

equipped), steering angle sensor (ESP

® model) and 

TCM (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”.

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, P2108, P2119 and/or P2135.

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

position (APP) sensor assembly.

1A-3 Engine General Information and Diagnosis: 

General Description

Statement of 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 inch). Accordingly, when 
any internal engine parts are serviced, care and 
cleanliness are important. Throughout this section, 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 surface 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.

• Throughout this manual, the 6 cylinders of the engine 

are identified by numbers;
No.1 (1), No.3 (3) and No.5 (5) of LH bank (7) and 
No.2 (2), No.4 (4) and No.6 (6) of RH bank (8) as 
counted from crankshaft pulley side (9) to flywheel 
side (10).

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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ECM in this vehicle has the following functions.
• When the ignition switch is turned ON with the engine 

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

• When ECM detects a malfunction which gives an 

adverse effect to vehicle emission while the engine is 
running, it makes the malfunction indicator lamp 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 (DTC according to SAE J2012) in its 
memory.
(If it detects that continuously 3 driving cycles are 
normal after detecting a malfunction, however, it 
makes MIL 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 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.)

7

5

3

1

9

10

2

4

6

8

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Engine General Information and Diagnosis:  1A-4

• It is possible to communicate via DLC (data link 

connector) (2) by using not only SUZUKI scan tool (3) 
but also OBD generic scan tool.

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 driving mode 
where a malfunction would be detected if present and 
next engine startup.

2 Driving Cycle Detection Logic
The malfunction detected in the first driving cycle is 
stored in ECM memory (in the form of pending DTC and 
freeze frame data) 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
ECM stores the engine and driving conditions (in the 
form of data as shown) 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 the 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.

An example of freeze frame data

1

(A)

1

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[A]: 1st, 2nd or 3rd in parentheses here represents which position in the 

order the malfunction is detected.

[A]

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