ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-23
ENGINE BASIC INSPECTION
This check is very important for troubleshooting when ECM has detected no DTC and no abnormality has been
found in visual inspection.
Follow the flow table carefully.
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE”.
2 Check battery voltage.
Is it 11 V or more?Go to Step 3. Charge or replace battery.
3 Is engine cranked? Go to Step 4. Go to “DIAGNOSIS” in
Section 6G.
4 Does engine start? Go to Step 5. Go to Step 7.
5 Check idle speed as follows :
1) Warm up engine to normal operating temp.
2) Shift transmission to neutral position for M/T
(“P” position for A/T).
3) All of electrical loads are switched off.
4) Check engine idle speed with scan tool.
See Fig. 1.
Is it 650 – 750 r/min (700 – 800 r/min. for A/T
vehicle)?Go to Step 6. Go to “ENGINE DIAGNO-
SIS TABLE”.
6 Check ignition timing as follows :
1) When SUZUKI scan tool is not available,
disconnect scan tool from DLC and connect
test switch terminal of monitor connector to
ground. See Fig. 2.
When using SUZUKI scan tool, select
“MISC” mode on SUZUKI scan tool and fix
ignition timing to initial one. See Fig. 3.
2) Using timing light (1), check initial ignition
timing. See Fig. 4.
Is it 5° ± 3° BTDC at specified idle speed?Go to “ENGINE DIAGNO-
SIS TABLE”.Check ignition control
related parts referring to
Section 6F1.
7 Is immobilizer control system equipped? Go to Step 8. Go to Step 9.
8 Check immobilizer system malfunction as fol-
lows.
1) Check immobilizer indicator lamp or MIL
(malfunction indicator lamp) for flashing.
Is it flashing when ignition switch is turned to
ON position?Go to “DIAGNOSIS” in
Section 8G.Go to Step 9.
9 Check fuel supply as follows :
1) Check to make sure that enough fuel is
filled in fuel tank.
2) Turn ON ignition switch for 2 seconds and
then OFF. See Fig. 5.
Is fuel pressure felt from fuel feed hose (1)
when ignition switch is turned ON?Go to Step 11. Go to Step 10.
10 Check fuel pump for operating.
Was fuel pump operating sound heard from fuel
filler for about 10 seconds after ignition switch
ON and stop?Go to “DIAG. FLOW
TABLE B-3”.Go to “DIAG. FLOW
TABLE B-2”.
6-32 ENGINE GENERAL INFORMATION AND DIAGNOSIS
✱THROTTLE POS
(ABSOLUTE THROTTLE
POSITION)Ignition switch
ON/engine
stoppedThrottle valve fully closed 7 – 18%
Throttle valve fully open 70 – 90%
✱O2S B1 S1
(HEATED OXYGEN SEN-
SOR-1)At specified idle speed after warming up 0.01 – 0.95 V
∆✱O2S B1 S2
(HEATED OXYGEN SEN-
SOR-2)When engine is running at 2000 r/min. for 3
min or longer after warming up.0.01 – 0.95 V
∆✱O2S FT B1 S1 At specified idle speed after warning up– 20 – +20%
∆✱DIS. WITH MIL ON––
DESIRED IDLE
(DESIRED IDLE SPEED)At idling with no load after warming up, M/T
at neutral, A/T at “P” rangeM/T 700 r/min
A/T 750 r/min
TP SENSOR VOLT
(THROTTLE POSITION
SENSOR OUTPUT VOLT-
AGE)Ignition switch
ON/engine
stoppedThrottle valve fully closed More than 0.2 V
Throttle valve fully open Less than 4.8 V
INJ PULSE WIDTH
(FUEL INJECTION PULSE
WIDTH)At specified idle speed with no load after
warming up2.0 – 3.6 msec.
At 2500 r/min with no load after warming up 2.0 – 3.6 msec.
IAC FLOW DUTY
(IDLE AIR CONTROL
FLOW DUTY)At idling with no load after warming up 5 – 25%
TOTAL FUEL TRIM At specified idle speed after warming up– 35 – +35%
BATTERY VOLTAGE Ignition switch ON/engine stop 12 – 14 V
CANIST PRG DUTY
(EVAP CANISTER PURGE
FLOW DUTY)–0 – 100%
CLOSED THROT POS
(CLOSED THROTTLE
POSITION)Throttle valve at idle position ON
Throttle valve opens larger than idle posi-
tionOFF
FUEL CUT When engine is at fuel cut condition ON
Other than fuel cut condition OFF
RADIATOR FAN
(RADIATOR FAN CON-
TROL RELAY)Ignition switch
ONEngine coolant temp. :
Lower than 95°C (203°F)OFF
Engine coolant temp. :
97.5°C (208°F) or higherON
ELECTRIC LOAD Ignition switch ON/Headlight, small light
and rear window defogger all turned OFFOFF
Ignition switch ON/Headlight, small light or
rear window defogger turned ONON
A/C SWITCH Engine running after warming up, A/C not
operatingOFF
Engine running after warming up, A/C oper-
atingON SCAN TOOL DATA VEHICLE CONDITION NORMAL CONDITION/
REFERENCE VALUES
6-34 ENGINE GENERAL INFORMATION AND DIAGNOSIS
IGNITION ADVANCE (IGNITION TIMING ADVANCE FOR NO.1 CYLINDER, °)
Ignition timing of NO.1 cylinder is commanded by ECM. The actual ignition timing should be checked by using
the timing light.
INTAKE AIR TEMP. (°C, °F)
It is detected by intake air temp. sensor and used to determine the amount of air passing into the intake manifold
as air density varies with temperature.
MAF (MASS AIR FLOW RATE, gm/s, lb/min)
It represents total mass of air entering intake manifold which is computed based on signals from MAP sensor,
IAT sensor, TP sensor, etc.
THROTTLE POS (ABSOLUTE THROTTLE POSITION, %)
When throttle position sensor is fully closed position, throttle opening is indicated as 0% and 100% full open
position.
OXYGEN SENSOR B1 S1 (HEATED OXYGEN SENSOR-1, V)
It indicates output voltage of HO2S-1 installed on exhaust manifold (pre-catalyst).
OXYGEN SENSOR B1 S2 (HEATED OXYGEN SENSOR-2, V)
It indicates output voltage of HO2S-2 installed on exhaust pipe (post-catalyst). It is used to detect catalyst dete-
rioration.
DESIRED IDLE (DESIRED IDLE SPEED, rpm)
The Desired Idle Speed is an ECM internal parameter which indicates the ECM requested idle. If the engine is
not running, this number is not valid.
TP SENSOR VOLT (THROTTLE POSITION SENSOR OUTPUT VOLTAGE, V)
The Throttle Position Sensor reading provides throttle valve opening information in the form of voltage.
INJ PULSE WIDTH (FUEL INJECTION PULSE WIDTH, msec.)
This parameter indicates time of the injector drive (valve opening) pulse which is output from ECM (but injector
drive time of NO.1 cylinder for multiport fuel injection).
IAC FLOW DUTY (IDLE AIR (SPEED) CONTROL DUTY, %)
This parameter indicates current flow time rate within a certain set cycle of IAC valve (valve opening rate) which
controls the amount of bypass air (idle speed).
TOTAL FUEL TRIM (%)
The value of Total Fuel Trim is obtained by putting values of short Term Fuel Trim and Long Term Fuel Trim
together. This value indicates how much correction is necessary to keep the air/fuel mixture stoichiometrical.
BATTERY VOLTAGE (V)
This parameter indicates battery positive voltage inputted from main relay to ECM.
CANIST PURGE DUTY (EVAP CANISTER PURGE FLOW DUTY, %)
This parameter indicates valve ON (valve open) time rate within a certain set cycle of EVAP purge solenoid
valve which controls the amount of EVAP purge.
0% means that the purge valve is completely closed while 100% is a fully open valve.
CLOSED THROTTLE POSITION (ON/OFF)
This parameter will read ON when throttle valve is fully closed, or OFF when the throttle is not fully closed.
FUEL CUT (ON/OFF)
ON : Fuel being cut (output signal to injector is stopped)
OFF : Fuel not being cut
6-36 ENGINE GENERAL INFORMATION AND DIAGNOSIS
INSPECTION OF ECM AND ITS CIRCUITS
ECM and its circuits can be checked at ECM wiring couplers by
measuring voltage and resistance.
VOLTAGE CHECK
1) Remove ECM (1) from vehicle body referring to Section 6E.
2) Check voltage at each terminal of couplers (2) connected.CAUTION:
ECM cannot be checked by itself. It is strictly prohibited
to connect voltmeter or ohmmeter to ECM with coupler
disconnected from it.
NOTE:
As each terminal voltage is affected by the battery volt-
age, confirm that it is 11 V or more when ignition switch
is ON.
1
1. ECM
2. ECM couplers (Viewed from harness side)
C42 (31P) C41 (24P) G02 (17P)1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 28 27 29 30 315 6
1 2 3 4 5 6 7
11 12
9 10 11 13 12 14 15 16
16 171 2
7 8
13 14 3 4
9 10
15 17 188
19 20 21 22 23 24
2
1
6-46 ENGINE GENERAL INFORMATION AND DIAGNOSIS
TABLE A-1 MALFUNCTION INDICATOR LAMP CIRCUIT CHECK - LAMP DOES
NOT COME “ON” AT IGNITION SWITCH ON (BUT ENGINE AT STOP)
WIRING DIAGRAM
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, ECM causes the main relay to turn ON (close the contact point). Then,
ECM being supplied with the main power, turns ON the malfunction indicator lamp (MIL). When the engine
starts to run and no malfunction is detected in the system, MIL goes OFF but if a malfunction was or is detected,
MIL remains ON even when the engine is running.
INSPECTION
1. BATT fuse 3. IG METER fuse 5. Monitor connector 7. To ignition switch
2. Main fuse box 4. To battery 6. MIL
[A] : Case of TYPE A is shown
(See NOTE)[B] : Case of TYPE B is shown
(See NOTE)
1
12V5V
ECM
23
+BB
DA
C
BLK/WHT
BRN/WHT
BLK/RED
BLK/RED
C42 (31P) C41 (24P) G02 (17P)1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 28 27 29 30 315 6
1 2 3 4 5 6 7
11 12
9 10 11 13 12 14 15 16
16 171 2
7 8
13 14 3 4
9 10
15 17 188
19 20 21 22 23 24
BLK
DN
TS
GNDMON
PPL/WHTC42-27 [A]
C42-16 [A]
PNK/BLUC42-28 [A]
7 4
G02-1 [A]IG1
5
6IG1
WHT/GRN
BLK/WHT
G02-6 [A]
C41-5 C41-6 C41-10 C41-11 [B]C41-14 [B]
C41-15 [B]
C41-8 [B]
G02-9 [B]
PPL/WHT
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
Step Action Yes No
1 MIL Power Supply Check
1) Turn ignition switch ON.
Do other indicator/warning lights in combination
meter comes ON?Go to Step 2.“IG METER” fuse blown,
main fuse blown, ignition
switch malfunction, “BLK/
WHT” circuit between “IG
METER” fuse and combi-
nation meter or poor cou-
pler connection at
combination meter.
2 ECM Power and Ground Circuit Check
Does engine start?Go to Step 3. Go to TABLE A-5 ECM
POWER AND GROUND
CIRCUIT CHECK.
If engine is not cranked,
go to DIAGNOSIS in Sec-
tion 6G.
ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-49
TABLE A-5 ECM POWER AND GROUND CIRCUIT CHECK - MIL DOESN’T
LIGHT AT IGNITION SWITCH ON AND ENGINE DOESN’T START THOUGH IT IS
CRANKED UP
WIRING DIAGRAM
CIRCUIT DESCRIPTION
When the ignition switch tuned ON, the main relay turns ON (the contact point closes) and the main power is
supplied to ECM.
1. BATT fuse 3. IG METER fuse 5. Monitor connector
2. Main fuse box 4. To battery 6. MIL (if equipped)
[A] : Case of TYPE A is shown (See NOTE) [B] : Case of TYPE B is shown (See NOTE)
1
12V5V
ECM
23
+BB
DA
C
BLK/WHT
BRN/WHT
BLK/RED
BLK/RED
C42 (31P) C41 (24P) G02 (17P)1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 28 27 29 30 315 6
1 2 3 4 5 6 7
11 12
9 10 11 13 12 14 15 16
16 171 2
7 8
13 14 3 4
9 10
15 17 188
19 20 21 22 23 24
BLK
DN
TS
GNDMON
PPL/WHTC42-27 [A]
C42-16 [A]
PNK/BLUC42-28 [A]
7 4
G02-1 [A]IG1PPL/YEL [A]
5
6IG1
WHT/GRN
BLK/WHT
G02-6 [A]
C41-5 C41-6 C41-10 C41-11 [B]C41-14 [B]
C41-15 [B]
C41-8 [B]
G02-9 [B]PPL/WHT [B]
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
6-50 ENGINE GENERAL INFORMATION AND DIAGNOSIS
INSPECTION
Step Action Yes No
1 Main Relay Operating Sound Check
Is operating sound of main relay heard at ignition switch
ON?Go to Step 5. Go to Step 2.
2 Main Relay Check
1) Turn OFF ignition switch and remove main relay (1).
2) Check for proper connection to main relay (1).
3) Check resistance between each two terminals. See Fig.
1 and 2.
Between terminals C and D : Infinity
Between terminals A and B : 56 – 146 Ω
4) Check that there is continuity between terminals C and
D when battery is connected to terminals A and B. See
Fig. 3.
Is main relay in good condition?Go to Step 3. Replace main relay.
3 Fuse Check
Is main fuse in good condition? See Fig. 4.Go to Step 4. Check for short in
circuits connected
to this fuse.
4 ECM Power Circuit Check
1) Turn OFF ignition switch, disconnect connectors from
ECM and install main relay.
2) Check for proper connection to ECM at terminals G02-6
(Case of TYPE A. See NOTE) or C41-11 (Case of TYPE
B. See NOTE), C41-10, C41-5 and C41-6.
3) If OK, then measure voltage between terminal G02-6
(Case of TYPE A. See NOTE) or C41-11 (Case of TYPE
B. See NOTE) and ground, C41-10 and ground with igni-
tion switch ON.
Is each voltage 10 – 14 V?Go to Step 5.“BLK/WHT”, “BLK/
YEL” or “BRN/
WHT” circuit open.
5 ECM Power Circuit Check
1) Using service wire, ground terminal C41-10 and mea-
sure voltage between terminal C41-5 and ground at igni-
tion switch ON.
Is it 10 – 14 V?Check ground cir-
cuits “BRN/WHT”
and “BLK/YEL” for
open.
If OK, then substi-
tute a known-good
ECM and recheck.Go to Step 6.
6 Is operating sound of main relay heard in Step 1? Go to Step 7.“BLK/YEL” or “BLK/
RED” wire open.
7 Main relay check
1) Check main relay according to procedure in Step 2.
Is main relay in good condition?“BLK/YEL” or “BLK/
RED” wire open.Replace main relay.
6-54 ENGINE GENERAL INFORMATION AND DIAGNOSIS
Fig. 1 for Step 2
Fig. 2 for Step 33 Check Wire Harness.
1) Disconnect MAP sensor connector with
ignition switch OFF.
2) Check for proper connection of MAP sensor
at “RED/WHT” and “GRY/RED” wire termi-
nals.
3) If OK, then with ignition switch ON, check
voltage between each of “GRY/RED” or
“RED/WHT” wire terminals and body
ground. See Fig. 2.
Is voltage about 4 – 6 V at each terminal?Go to Step 4.“GRY/RED” wire open or
shorted to ground circuit
or shorted to power circuit
(See NOTE), “RED/WHT”
wire open or shorted to
ground, poor C42-26 con-
nection or C42-22 con-
nection.
If wire and connection are
OK, confirm that MAP
sensor is normal and then
substitute a known-good
ECM and recheck.
4 Check MAP sensor.
Check MAP sensor according to “MAP Sensor
Individual Check” mentioned previously.
Is it in good condition?“GRY/RED” wire shorted
to “ORN” wire, “RED/
WHT” wire open, poor
C42-10 connection.
If wire and connection are
OK, substitute a known-
good ECM and recheck.Replace MAP sensor. Step Action Yes No
NOTE:
When battery voltage is applied to “GRY/RED” wire, it is possible that MAP sensor is also faulty.