1999 SUZUKI GRAND VITARA ecm

YH4
GRAND
VITARA
1. Coupler
2. Probe
1. Coupler
2. Probe
3. Where male
terminal fits
0A-10 GENERAL INFORMATION
PRECAUTIONS FOR ELECTRICAL CIRCUIT
SERVICE

When disconnecting and connecting coupler, make sure to
turn ignition switch OFF, or electronic parts may get dam-
aged.

Be careful not to touch the electrical terminals of parts which
use microcomputers (e.g. electronic control unit like as
ECM, PCM, P/S controller, etc.). The static electricity from
your body can damage these parts.

Never connect any tester (voltmeter, ohmmeter, or whatever)
to electronic control unit when its coupler is disconnected.
Attempt to do it may cause damage to it.

Never connect an ohmmeter to electronic control unit with
its coupler connected to it. Attempt to do it may cause dam-
age to electronic control unit and sensors.

Be sure to use a specified voltmeter / ohmmeter. Otherwise,
accurate measurements may not be obtained or personal in-
jury may result.

When taking measurements at electrical connectors using a
tester probe, be sure to insert the probe from the wire har-
ness side (backside) of the connector.

When connecting meter probe from terminal side of coupler
because it can't be connected from harness side, use extra
care not to bend male terminal of coupler of force its female
terminal open for connection.
In case of such coupler as shown connect probe as shown
to avoid opening female terminal.
Never connect probe where male terminal is supposed to fit.

YH4
GRAND
VITARA
0A-12 GENERAL INFORMATION
1. Check for loose connectionSensor
ECM
Check contact tension by
Inserting and removing just for
once
1. Looseness of crimping
2. Open
3. Thin wire (Single strand of wire)
ELECTRICAL CIRCUIT INSPECTION
PROCEDURE
While there are various electrical circuit inspection methods, de-
scribed here is a general method to check its open and short circuit
by using an ohmmeter and a voltmeter.
OPEN CIRCUIT CHECK
Possible causes for the open circuit are as follows. As the cause is
in the connector or terminal in many cases, they need to be checked
particularly carefully.

Loose connection of connector

Poor contact of terminal (due to dirt, corrosion or rust on it, poor
contact tension, entry of foreign object etc.)

Wire harness being open
When checking system circuits including an electronic control unit
such as ECM, TCM, ABS control module, etc., it is important to per-
form careful check, starting with items which are easier to check.
1) Disconnect negative cable from battery.
2) Check each connector at both ends of the circuit being checked
for loose connection. Also check lock condition of connector if
equipped with connector lock.
3) Using a test male terminal, check both terminals of the circuit be-
ing checked for contact tension of its female terminal.
Check each terminal visually for poor contact (possibly caused
by dirt, corrosion, rust entry of foreign object, etc.).
At the same time, check to make sure that each terminal is
locked in the connector fully.
4) Using continuity check or voltage check procedure described in
the following page, check the wire harness for open circuit and
poor connection with its terminals. Locate abnormality, if any.

YH4
GRAND
VITARA
GENERAL INFORMATION 0A-21
A
ABS : Anti-lock Brake System
ATDC : After Top Dead Center
API : American Petroleum Institute
ATF : Automatic Transmission Fluid
ALR : Automatic Locking Retractor
AC : Alternating Current
A / T : Automatic Transmission
A / C : Air Conditioning
ABDC : After Bottom Dead Center
A / F : Air Fuel Mixture Ratio
A-ELR : Automatic-Emergency
Locking Retractor
B
B+ : Battery Positive Voltage
BTDC : Before Top Dead Center
BBDC : Before Bottom Dead Center
C
CKT : Circuit
CMP Sensor : Camshaft Position Sensor
(Crank Angle Sensor, CAS)
CO : Carbon Monoxide
CPP Switch : Clutch Pedal Position Switch
(Clutch Switch, Clutch Start
Switch)
CPU : Central Processing Unit
CRS : Child Restraint System
D
DC : Direct Current
DLC : Data Link Connector
(Assembly Line Diag. Link,
ALDL, Serial Data Link, SDL)
DOHC : Double Over Head Camshaft
DOJ : Double Offset Joint
DRL : Daytime Running Light
DTC : Diagnostic Trouble Code
(Diagnostic Code)
E
EBCM : Electronic Brake Control
Module, ABS Control
Module
EBD : Electric Brake force Distribution
ECM : Engine Control Module
ECT Sensor : Engine Coolant Temperature
Sensor (Water Temp.
Sensor, WTS)
EGR : Exhaust Gas Recirculation
EGRT Sensor : EGR Temperature Sensor
(Recirculated Exhaust Gas
Temp. Sensor, REGTS)
EFE Heater : Early Fuel Evaporation
Heater (Positive Temperature
Coefficient, PTC Heater)
ELR : Emergency Locking Retractor
EPS : Electronic Power Steering
EVAP : Evaporative Emission
EVAP Canister : Evaporative Emission
Canister (Charcoal Canister)
F
4WD : 4 Wheel Drive
G
GEN : Generator
GND : Ground
H
HC : Hydrocarbons
HO2S : Heated Oxygen Sensor
I
IAC Valve : Idle Air Control Valve (Idle
Speed Control Solenoid
Valve, ISC Solenoid Valve)
IAT Sensor : Intake Air Temperature
Sensor (Air temperature
Sensor, ATS)
ICM : Immobilizer Control Module
IG : Ignition
ISC Actuator : Idle Speed Control Actuator
(Motor)
ABBREVIATIONS MAY BE USED IN THIS MANUAL

YH4
GRAND
VITARA
1A-4 HEATER AND VENTILATION
FOR LH VEHICLE
FOR RH VEHICLE
1. From ignition switch 1
2. From ignition switch 2
3. From blower fuse
4. Head light relay
5. To A / C controller6. Blower motor relay
7. Blower motor switch
8. Blower resistor
9. Blower motor
10. To ECM11. To illumination controller
(if equipped) or body ground
12. Mode control actuator
13. Mode control switch
14. From main fuse15. TAIL fuse 15 A
16. IG METER fuse 20 A
17. HEATER fuse 30 A
18. REAR DEFG fuse 15 A
19. Drive circuit
WIRING CIRCUIT

YH4
GRAND
VITARA
HEATER AND VENTILATION 1A-5
1. Blower unit
2. Blower motor resistor
3. Blower motor relay
4. Blower fan
5. Blower motor
3. Cover
ON-VEHICLE SERVICE
BLOWER UNIT
REMOVAL
1) Disconnect negative (±) cable at battery.
2) Disable air bag system, if equipped. Refer to DISABLING AIR
BAG SYSTEM in Section 10B.
3) Remove passenger lower member (1).
4) Remove ECM (1) with bracket (2) from blower motor unit (4).
5) Disconnect blower motor (1), blower motor relay (2) and resistor
lead wires (3) at couplers.

YH4
GRAND
VITARA
HEATER AND VENTILATION 1A-7
1. Fastening nuts
1. Air flow
BLOWER MOTOR
REMOVAL
1) Disconnect negative (±) cable at battery.
2) Disable air bag system, if equipped. Refer to DISABLING AIR
BAG SYSTEM in Section 10B.
3) Remove ECM with bracket from blower motor unit.
4) Disconnect harness clamps from dash panel.
5) Loosen three nuts fastening blower unit.
6) Disconnect blower motor lead wire at coupler (2).
7) Remove blower motor (3) from blower unit (1).
INSPECTION

Check continuity between terminal to terminal as shown in left fig-
ure.
If check results are continuity, proceed to next operation check.
If not, replace.

Connect battery to blower motor as shown, then check that the
blower motor operates smoothly and specified current.
Specified current: Max. 25 A at 12 V
INSTALLATION
1) Reverse removal procedure for installation.
2) Enable air bag system, if equipped. Refer to ENABLING AIR
BAG SYSTEM in Section 10B.

YH4
GRAND
VITARA
1B-6 AIR CONDITIONING (OPTIONAL)
DIAGNOSIS
GENERAL
ConditionPossible CauseCorrection
Cool air won't come out
(A / C system won't
operative)
No refrigerant

Fuse blown

A / C switch faulty

Blower motor switch faulty

A / C thermistor faulty

Dual pressure switch faulty

Wiring or grounding faulty

A / C ON permission signal in ECM
faulty

A / C controller and its circuit faultyRecover, evacuation and charging.
Check ªIG METERº fuse, ªREAR DEFGº
fuse, and ªA / C FUSEº and check for
short circuit to ground.
Check A / C switch.
Check blower motor switch.
Check A / C evaporator thermistor.
Check dual pressure switch.
Repair as necessary.
Check ON permission signal.
Check A / C controller and its circuit.
Cool air won't come out
(A / C compressor won't
operative)
Magnet clutch faulty

Compressor relay faulty

Compressor thermal switch faulty
(if equipped)

Drive belt loose or broken

Compressor faulty

A / C ON permission signal in ECM
faulty

A / C controller faultyCheck magnet clutch.
Check compressor thermal switch.
Check compressor relay.
Adjust or replace drive belt.
Check compressor.
Check ON permission signal.
Check A / C controller.
Cool air won't come out
(A / C condenser cooling
fan motor won't
operative)
Condenser cooling fan relay faulty

Wiring or grounding faulty

ªA / C condenser cooling fan relayº
signal in ECM faulty

Condenser cooling fan motor faultyCheck condenser cooling fan relay.
Repair as necessary.
Check A / C condenser cooling fan relay
signal.
Check condenser cooling fan motor.
Cool air won't come out
(Blower motor won't
operative)
Fuse blown

Blower motor relay faulty

Blower motor resistor faulty

Blower motor switch faulty

Wiring or grounding faulty

Blower motor faultyCheck ªHEATER FUSEº, ªREAR DEFGº
fuse and check for short circuit to
ground.
Check blower motor relay.
Check blower motor resistor.
Check blower motor switch.
Repair as necessary.
Check blower motor.
Cool air won't come out
or insufficient cooling
(A / C system normal
operative)
Insufficient or excessive charge of
refrigerant

Refrigerant leak in system

Condenser clogged

A / C evaporator clogged or frosted

A / C thermistor faulty

A / C controller faulty

Expansion valve faulty

Drive belt slipping

Magnetic clutch faultyCheck charge of refrigerant.
Check system for leaks.
Check condenser.
Check A / C evaporator.
Check A / C thermistor.
Check A / C controller.
Check expansion valve.
Check or replace drive belt.
Check magnetic clutch.

YH4
GRAND
VITARA
1. Blower motor main relay
2. Blower motor
3. Blower motor resistor
4. Blower motor switch
5. A / C controller
6. ECM
7. Heater mode control switch
8. Evaporator temperature sensor
9. Refrigerant pressure switch10. Compressor relay
11. Compressor
12. Condenser cooling fan relay
13. Condenser cooling fan
14. Fuse box
15. A / C fuse 25 A
16. Ignition switch
17. Main fuse box
18. Battery main fuse 80 A19. Battery
20. Generator
21. Ignition main fuse 60 A
22. Heater/A/C main fuse 60 A
23. Ignition / meter fuse 20 A
24. Rear defogger fuse 15 A
25. Heater fuse 30 A
26. Compressor thermal switch
(only IWATA production vehicle)
FOR LH VEHICLE
1B-16 AIR CONDITIONING (OPTIONAL)
WIRING CIRCUIT