ecm SUZUKI GRAND VITARA 2003 2.G Service Owner's Manual

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GRAND
VITARA
1. Malfunction indicator lamp (MIL)
2. Scan tool
3. DLC
4. Monitor connector
5. Diagnosis switch terminal
6. Ground terminal MIL
OFF
Time (sec.)
AUTOMATIC TRANSMISSION (4 A / T) 7B1-19
[For Vehicle with Monitor Connector]
ON-BOARD DIAGNOSTIC SYSTEM
For automatic transmission control system, PCM (ECM) has follow-
ing functions. Refer to Section 6 / 6-1 for details.

When the ignition switch is turned ON with the engine at a stop,
malfunction indicator lamp (MIL) turns ON to check the bulb of the
MIL.

When PCM detects a trouble in electronic shift control system, it
stores its trouble code in back-up memory in itself. (The memory
is kept as it is even if the trouble was only temporary and disap-
peared immediately. And it is not erased unless the power to PCM
is shut off for 30 seconds or longer.)

It is possible to communicate through DLC by using not only SU-
ZUKI scan tool (Tech-1) but also generic scan tool. (Diagnostic in-
formation can be accessed by using a scan tool.)

It is also possible to communicate by not using scan tool. PCM
indicates trouble area in memory by means of flashing of malfunc-
tion indicator lamp at the time of inspection (i.e. when diagnosis
switch terminal is grounded and ignition switch is turned ON).

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7B1-20 AUTOMATIC TRANSMISSION (4 A / T)
PRECAUTION IN DIAGNOSING TROUBLE

Don't disconnect couplers from PCM (ECM), battery cable from battery, PCM ground wire harness from engine
or main fuse before checking the diagnosis information (DTC, freeze frame data, etc.) stored in PCM memory.
Such disconnection will clear memorized information in PCM memory.

Using SUZUKI scan tool (Tech-1), or also generic scan tool for vehicle without monitor connector, the diagnostic
information stored in PCM memory can be checked and cleared as well. Before its use, be sure to read Operator's
(instruction) Manual supplied with it carefully to have good understanding of its functions and usage.

Priorities for diagnosing troubles (Only for vehicle without monitor connector)
If two or more diagnostic trouble codes (DTCs) are stored, proceed to the flow table of the DTC which was de-
tected 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.
1. Diagnostic trouble codes (DTCs) other than DTC P0171 / P0172 (Fuel system too lean / too rich) and DTC
P0400 (EGR flow malfunction)
2. DTC P0171 / P0172 (Fuel system too lean / too rich) and DTC P0400 (EGR flow malfunction)

Be sure to read ªPrecautions for Electrical Circuit Serviceº in Section 0A before inspection and observe what is
written there.

PCM replacement
When substituting a known-good PCM, check for following conditions.
Neglecting this check may result in damage to good PCM.
± All relays and actuators have resistance of specified value.
± MAF sensor, MDP sensor, TP sensor and fuel tank pressure sensor are in good condition. Also, the power
circuit of these sensors is not shorted to the ground.

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AUTOMATIC TRANSMISSION (4 A / T) 7B1-25
DIAGNOSTIC TROUBLE CODE (DTC) TABLE (A / T RELATED CODE) (cont'd)
DTC NO.MIL
Using
scan toolNot using
scan toolDETECTED ITEMDETECTING CONDITION
Vehicle
without
monitor
connectorVehicle
with
monitor
connector
*1
P0756
Not
applicableShift solenoid B (#2)
performance or stuck
offGear change control from PCM to
A / T does not agree with actual gear
position of A / T.2 driving
cyclesNot
applicable
P075863
64Shift solenoid B (#2)
electricalMonitor signal OFF is detected
when shift solenoid B (#2) is ON or
monitor signal ON is detected when
it is OFF.1 driving
cycleNot
applicable
*1
P1875
Not
applicable4WD low switch circuit
malfunctionDifference between vehicle speed
detected by VSS and vehicle speed
detected by output speed sensor
and compensated by 4WD low
switch is larger than specification.2 driving
cyclesNot
applicable
NOTE:
*1: Applicable to vehicle without monitor connector only.
FAIL-SAFE TABLE
When any of the following DTC is detected, ECM (PCM) enters fail-safe mode as long as malfunction continues
to exist but that mode is canceled when ECM detects normal condition after that.
DTC NO.
Using
scan toolNot using
scan toolTROUBLE AREAFAIL SAFE OPERATION
P0177
P011814
15ECT SENSOR
Each control except 4-A / T is permitted on the basis of
30.1C engine coolant temp.

4-A / T control is performed assuming 31C (engine warmed
up) or higher after 15 min. from engine start.
P0122
P012321
22TP SENSOR
Each control except 4-A / T is performed on the basis of 124
throttle valve opening.

4-A / T control is performed on the basis of 0 throttle valve
opening.
P070572TR SWITCHA / T control is performed in priority order of L, 2, N, D, R
and P.
P072075OUTPUT SPEED
SENSOR CIRCUIT
MALFUNCTIONA / T control is performed by using signal from VSS.
P075361
62SHIFT SOLENOID
A (#1)
A / T control using 3rd gear is performed when D range, 1st
or 2nd gear is used.

TCC solenoid OFF.
P075863
64SHIFT SOLENOID
B (#2)
A / T control using 4th gear is performed when D range 2nd
or 3rd gear is used.

When both shift solenoid A (#1) and B (#2) failed
simultaneously, A / T control using 4th gear is always
performed in D range.

TCC solenoid OFF.
P074365
66TCC (Lock-up)
SOLENOIDTCC (lock-up) solenoid OFF.

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AUTOMATIC TRANSMISSION (4 A / T) 7B1-27
A / T BASIC CHECK
This inspection is important for troubleshooting when PCM (ECM) has detected no DTC and no abnormality has
been noted in visual inspection.
Follow flow table carefully.
STEP
ACTIONYESNO
1Was ªA / T DIAG. FLOW TABLEº performed?Go to Step 2.Go to ªA / T DIAG.
FLOW TABLEº.
2Perform MANUAL ROAD TEST in this section.
Is it OK?Go to Step 3.Go to Step 4.
3Proceed to TROUBLE DIAGNOSIS TABLE 1 in this
section.
Is trouble identified?Repair or replace
defective parts.Go to Step 5.
4Perform stall test, time rag test, line pressure test,
engine brake test and ªPº range test referring to STALL
TEST, LINE PRESSURE TEST, ENGINE BRAKE
TEST and ªPº RANGE TEST in this section.
Are the test results satisfactory?Go to Step 5.Proceed to
TROUBLE DIAGNO-
SIS TABLE 3 in this
section.
5Proceed to TROUBLE DIAGNOSIS TABLE 2 in this
section.
Is trouble identified?Repair or replace
defective parts.Proceed to
TROUBLE DIAGNO-
SIS TABLE 3 in this
section.

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1. 4WD switch
2. Transfer
3. Blank
4. Blank
5. ECM or PCM
6. Glove box7. Air pump assembly
8. Actuator
9. Axle lock clutch
10. Free axle hub
11. 4WD indicator lamp
7E-2 DIFFERENTIAL (FRONT)
4WD CONTROL SYSTEM
When the 4WD switch is turned ON by shifting the transfer shift lever, ECM (PCM) (G16 and J20 engine models)
or 4WD controller (H25 engine model) actuates (energizes) the air pump assembly. Then positive pressure is sent
from the air pump assembly to the actuator installed to the differential case and causes the axle lock clutch and
the free axle hub in the differential case to be engaged, resulting in the 4WD mode. Only when running in the 4WD
mode, front axles are joined to differential case, and they become free when 2WD mode is used (or when transfer
shift lever is shifted to N position), thereby reducing the power loss.

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1. 4WD switch
2. Air pump assembly
3. Pump motor
4. Release valve
5. Pressure switch6. Transfer
7. Front differential
8. Air hose and pipe
9. 4WD indicator lamp
10. To ignition switch
11. ECM or PCM
Operation
(refer to ªComponents and Functionsº)
Power supply
(from ECM or PCM)
DIFFERENTIAL (FRONT) 7E-3
System Circuit and Operation

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7E-4 DIFFERENTIAL (FRONT)
Components and Functions
ComponentFunction
4WD switch
When the transfer shift lever is shifted to 4L or 4H position, this switch turns ON
and causes the 4WD control system to turn ON, unless it is shifted to N or 2H
within 1 second.
ECM or PCM
When the 4WD switch turns ON [unless it turns OFF within 1 second], this com-
ponent actuates the pump assembly. If the pressure in the air pump assembly
fails to increase higher than the set level even after the pump motor has run more
than 10 seconds, this component stops the motor to protect it.
Air pump assembly

Pump motor

Release valve

Pressure switchThe air pump assembly consists of a pump motor, release valve and a pressure
switch.
Pump motor:
Produces positive pressure which actuates the actuator.
Release valve:
Closes when transfer shift lever is shifted to 4H or 4L so that the positive pressure
is applied to the actuator, and opens when N or 2H to release the pressure to the
atmosphere.
Pressure switch:
Turns ON and OFF depending on the pressure level in the pump assembly
(whether higher or lower than the set pressure level). ECM or PCM detects the
pressure level through this switch.
Differential case assembly

Free axle hub

Axle lock clutch

ActuatorThe free axle hub, axle lock clutch and actuator are installed in the differential
left case. The positive pressure produced in the air pump assembly is applied
to the actuator which then pushes the axle lock clutch to be engaged with the free
axle hub. In this state, the drive force is transmitted to the front axle, resulting in
the 4WD mode.
When the actuator is free from the positive pressure [when it is under the atmo-
spheric pressure], the axle lock clutch is pushed back by the return spring force
and cannot be engaged with the free axle hub, resulting in the 2WD mode.
ª4WDº indicator lampIt lights up when 4WD control system is in the 4WD mode.

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7E-6 DIFFERENTIAL (FRONT)
STEPACTIONYESNO
1Turn ON ignition switch (but engine at stop) and
check malfunction indicator lamp.
Does lamp light up?Go to step 2.A trouble has
occurred at some
place. Repair it
referring to
MALFUNCTION
INDICATOR LAMP
(ªCHECK ENGINEº
LAMP) CHECK in
DIAGNOSIS of
SECTION 6.
2Check 4WD switch circuit.
Turn ignition switch ON and check that voltage
between terminal C51-2-18 and terminal C51-3-17
(ground) for G16 / J20 (terminal C51-1-11 and terminal
C51-3-26 (ground) for H25) is as follows.

When transfer shift lever is in N or 2H: 10 ± 14 V

When transfer shift lever is in 4L or 4H: 0 ± 1 V
Is the check result satisfactory?Go to step 3.Check 4WD switch
(refer to SECTION
7A), ªB / Orº and ªBº
circuits of 4WD
switch.
If OK, substitute a
known-good ECM
(PCM) and recheck.
3Check power supply.
1) Turn ignition switch ON.
2) Check voltage between C51-2-7 and C51-3-17
(ground) for G16 / J20 (C51-1-15 and C51-3-26
(ground) for H25). The check results should be as
follows.

When transfer shift lever is in N or 2H: 0 ± 1 V

When transfer shift lever is in 4L or 4H: 10 ± 14 V
Is the check result satisfactory?Go to step 4.Check ªRº circuit. If
it is OK, substitute a
known-good ECM
(PCM) and recheck.
4Check air pump assembly circuit.
1) Check for proper connection to air pump
assembly at all terminals.
2) Turn ignition switch ON.
3) Check voltage between C51-2-27 and C51-3-17
(ground) for G16 / J20 (C51-1-18 and C51-3-26
(ground) for H25). The check result should be as
follows.

When transfer shift lever is in 2H or N: 0 ± 1 V

When transfer shift lever is in 4L or 4H
(more than 4 seconds after shifted to 4L or 4H):
10 ± 14 V
Is the check result satisfactory?Go to step 5.Check air pump
assembly referring
to ªON-VEHICLE
SERVICEº, and then
ªPº circuit.
If OK, substitute a
known-good ECM
(PCM) and recheck.
5Check 4WD indicator lamp circuit.
1) Turn ignition switch ON.
2) Check voltage between E61-19 and C51-3-17
(ground) for G16 / J20 (C51-1-7 and C51-3-26
(ground) for H25). The check result should be as
follows.

When transfer shift lever is in 2H or N: 10 ± 14 V

When transfer shift lever is in 4L or 4H: 0 ± 1 V
Is the check result satisfactory?4WD control system
is in good condition.Check ªOr / Bº circuit
(including indicator
lamp and
combination meter).
If OK, substitute a
known-good ECM
(PCM) and recheck.

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DIFFERENTIAL (FRONT) 7E-7
1
1. ECM (PCM); viewed from harness side
4WD CONTROL CIRCUIT INSPECTION
Voltage Check [G16 and J20 engine models]
Check for input or output voltage (voltage between each circuit and
body ground) of ECM (PCM) with ECM (PCM) connector con-
nected and ignition switch turned ON.
TER-
MINALCIRCUITWIRE
COLORNORMAL
VOLTAGECONDITION
E6110 ± 14 VTransfer shift lever: 2H or NE61-
194WD Indicator lampOr / B0 ± 1 V4 seconds after transfer shift lever shifted
to 4H or 4L
C51 2Air pump assembly0 ± 1 VTransfer shift lever: 2H or NC51-2
-7(Pump motor and release
valve)R10 ± 14 V1 seconds after transfer shift lever shifted
to 4H or 4L
C51-24WD switchB/Or10 ± 14 VTransfer shift lever: 2H or N
-184WD switchB/Or0 ± 1 VTransfer shift lever: 4H or 4L
C51-
3-17GroundB/Bl0 ± 1 V±
C51 2Airpumpassembly0 ± 1 VTransfer shift lever: 2H or NC51-2
-27
Air um assembly
(pressure switch)P10 ± 14 V4 seconds after transfer shift lever shifted
to 4H or 4L

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7E-8 DIFFERENTIAL (FRONT)
1. ECM (PCM); viewed from harness side
Voltage Check [H25 engine model]
TER-
MINALCIRCUITWIRE
COLORNORMAL
VOLTAGECONDITION
C51 110 ± 14 VTransfer shift lever: 2H or NC51-1
-74WD Indicator lampOr / B0 ± 1 V4 seconds after transfer shift lever shifted
to 4H or 4L
C51 1Air pump assembly0 ± 1 VTransfer shift lever: 2H or NC51-1
-15(Pump motor and release
valve)R10 ± 14 V1 seconds after transfer shift lever shifted
to 4H or 4L
C51-14WD switchB/Or10 ± 14 VTransfer shift lever: 2H or N
-114WD switchB/Or0 ± 1 VTransfer shift lever: 4H or 4L
C51-3
-26GroundB/Bl0 ± 1 V±
C51-1Airpumpassembly0 ± 1 VTransfer shift lever: 2H or NC51-1
-18
Air um assembly
(pressure switch)P10 ± 14 V4 seconds after transfer shift lever shifted
to 4H or 4L