Page 509 of 801
YH4
GRAND
VITARA
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
Page 552 of 801
YH4
GRAND
VITARA
8C-10 INSTRUMENTATION / DRIVER INFORMATION
G16
J20
H25
1. ECT sensor
1
ENGINE COOLANT TEMP. (ECT) METER AND
SENSOR
ENGINE COOLANT TEMPERATURE (ECT) METER
INSPECTION
1) Disconnect Y/W lead wire going to ECT sensor.
2) Turn ignition switch ON, and check that ECT meter indicates
COOL.
3) Turn ignition switch OFF.
4) Ground Y/W lead wire through a 3.4 W test bulb (1) as illustrated.
5) Turn ignition switch ON, and check that bulb light up and pointer
(2) moves to hot side.
6) If ECT meter shows no operation, repair or replace defective
parts.
ENGINE COOLANT TEMPERATURE (ECT) SENSOR
REMOVAL AND INSTALLATION
Refer to ECT SENSOR in ON-VEHICLE SERVICE in Section 6E1
(for G16 and J20) or Section 6E2 (for H25) of this manual for details.
Page 553 of 801
YH4
GRAND
VITARA
G16
J20
H25
1. Oil pressure switch
INSTRUMENTATION / DRIVER INFORMATION 8C-11
INSPECTION
1) Warm up ECT sensor (1) observing resistance between sensor
terminal (2) and sensor unit (1). Resistance should be de-
creased with increase of its temperature.
2) Check resistance between sensor terminal (2) and sensor unit
(1) shown below. If check result is not as specified, replace sen-
sor.
Temperature
Resistance
50C (122F)136 ± 216
OIL PRESSURE LIGHT
OIL PRESSURE SWITCH
REMOVAL AND INSTALLATION
Refer to OIL PRESSURE CHECK in Section 6A1 (for G16), Section
6A2 (for H25), and Section 6A4 (for J20) of this manual for details.
INSPECTION
1) Disconnect oil pressure switch (1) lead wire.
2) Check for continuity between oil pressure switch terminal (2)
and cylinder block (3) as shown.
During Engine Running
No continuity
At Engine StopContinuity
If check result is not as specified, replace oil pressure switch (1).
Page 603 of 801

YH4
GRAND
VITARA
IMMOBILIZER CONTROL SYSTEM (IF EQUIPPED) 8G-15
1. Main fuse
2. Main relay
3. ECM/PCM
4. Immobilizer indicator lamp
(Vehicle not equipped with
monitor coupler) For G16 / J20 engine For H25 engine
G16 / J20 Engine
H25 Engine
TABLE B IMMOBILIZER INDICATOR LAMP CHECK
(IMMOBILIZER INDICATOR LAMP DOSE NOT LIGHT AT IGNITION
SWITCH ON)
STEPACTIONYESNO
11) Turn ignition switch ON.
Do other indicator / warning lights in
combination meter come ON?Go to Step 2.ªIGº fuse blown, main fuse blown,
ignition switch malfunction,
ªB / Wº circuit between ªIGº fuse
and combination meter or poor
coupler connection at
combination meter.
21) Turn ignition switch OFF and
disconnect connectors from ECM /
PCM.
2) Check for proper connection to ECM /
PCM at terminal E61-5 for G16 / J20
engine or E61-23 for H25 engine.
3) If OK, then using service wire, ground
terminal E61-5 for G16 / J20 engine or
E61-23 for H25 engine in connector
disconnected.
Does immobilizer indicator lamp turn on
at ignition switch ON?Substitute a known-
good ECM / PCM and
recheck.Bulb burned out or ª(b)º wire
circuit open.
Page 604 of 801
YH4
GRAND
VITARA
8G-16 IMMOBILIZER CONTROL SYSTEM (IF EQUIPPED)
1. Main fuse
2. Main relay
3. ECM / PCM
4. Immobilizer indicator lamp
(Vehicle not equipped with
monitor coupler) For G16 / J20 engine For H25 engine
G16 / J20 Engine
H25 Engine
TABLE C IMMOBILIZER INDICATOR LAMP CHECK
(IMMOBILIZER INDICATOR LAMP REMAINS ON AFTER ENGINE
STARTS)
STEPACTIONYESNO
11) With ignition switch OFF, disconnect
couplers from ECM / PCM.
Does immobilizer indicator lamp turn ON
at ignition switch ON?ª(p)º wire shorted to
ground circuit.Substitute a known-good ECM /
PCM and recheck.