Page 149 of 557

6-98 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
Main
fuseIgnition
switchTo other circuits
Main
relay
Fuel pump relay
Fuel pump
CAUTION: Check to make sure that connection is
made between correct terminals. Wrong connection
can cause damage to ECM (PCM), wire harness, etc.
TABLE B-2 FUEL PUMP AND ITS CIRCUIT CHECK
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE
DIAG. FLOW
TABLE”.
2Check Fuel Pump Control System for Operation. See Fig. 1.
Is fuel pump heard to operate for 2 sec. after ignition switch
ON?Fuel pump circuit
is in good
condition.Go to Step 3.
3Check Fuel Pump for Operation.
1) Remove fuel pump relay from relay box with ignition
switch OFF.
2) Check for proper connection to relay at each terminals.
3) If OK, using service wire, connect terminals E28-1 and
E28-2 of relay connector. See Fig. 2.
Is fuel pump heard to operate at ignition switch ON?Go to Step 4.“P”, “B” or “W/Bl”
circuit open or fuel
pump malfunction.
4Check Fuel Pump Relay for Operation.
1) Check resistance between each two terminals of fuel
pump relay. See Fig.3.
Between terminals “1” and “2”: Infinity
Between terminals “3” and “4”: 100 – 120 Ω
2) Check that there is continuity between terminals “1” and
“2” when battery is connected to terminals “3” and “4”. See
Fig. 4.
Is fuel pump relay in good condition?“P/W” circuit open
or poor C02-21
connection.
If wire and
connection are
OK, substitute a
known-good ECM
(PCM) and
recheck.Replace fuel pump
relay.
Page 150 of 557
ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-99
Fig. 1 for Step 2 Fig. 2 for Step 3
1. Service wire
2. Relay box
Fig. 3 for Step 4
Fig. 4 for Step 4
Page 151 of 557

1. Fuel pump
2. Fuel filter
3. Throttle body
4. Fuel injector
5. Fuel pressure regulator6. Special tool
(Fuel pressure gauge &
3-way joint)
7. Fuel feed line
8. Fuel return line
6-100 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
TABLE B-3 FUEL PRESSURE CHECK
INSPECTION
STEPACTIONYESNO
1Check Fuel Pressure (Refer to Section 6E1 for details).
1) Release fuel pressure from fuel feed line.
2) Install fuel pressure gauge.
3) Check fuel pressure by repeating ignition switch
ON and OFF. See Fig. 1.
Is fuel pressure then 160 – 210 kPa (1.6 – 2.1 kg / cm
2,
22.7 – 29.9 psi)?
Go to Step 2.Go to Step 4.
2Is 90 kPa (0.9 kg / cm2, 12.8 psi) or higher fuel
pressure retained for 1 minute after fuel pump is
stopped at Step 1?Normal fuel pressure.Go to Step 3.
31) Start engine and warm it up to normal operating
temperature.
2) Keep it running at specified idle speed.
Is fuel pressure then within 90 – 140 kPa
(0.9 – 1.4 kg / cm
2, 12.8 – 20.0 psi)?
Normal fuel pressure.Clogged vacuum
passage for fuel
pressure regulator
or
Faulty fuel pressure
regulator.
4Is there fuel leakage from fuel feed line hose, pipe or
their joint?Fuel leakage from
hose, pipe or joint.Go to Step 10.
5Was fuel pressure higher than specification in Step 1?Go to Step 6.Go to Step 7.
61) Disconnect fuel return hose from throttle body and
connect new return hose to it.
2) Insert the other end of new return hose into
approved gasoline container.
3) Operate fuel pump.
Is specified fuel pressure obtained then?Restricted fuel return
hose or pipe.Faulty fuel pressure
regulator.
7Was no fuel pressure supplied in Step 1?Go to Step 8.Go to Step 9.
Page 152 of 557

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-101
Fig. 1 for Step 1
1. Fuel pressure gauge & 3way joint
STEPACTIONYESNO
8With fuel pump operated and fuel return hose
blocked by pinching it, is fuel pressure applied?Faulty fuel pressure
regulator.Shortage of fuel or fuel
pump or its circuit
defective (refer to B-2
FUEL PUMP ANDITS
CIRCUIT CHECK).
91) Operate fuel pump.
2) With fuel return hose blocked by pinching it, check
fuel pressure.
Is it 450 kPa (4.5 kg / cm
2, 63.9 psi) or more?
Faulty fuel pressure
regulator.Clogged fuel filter,
Restricted fuel feed
hose or pipe,
Faulty fuel pump or
Fuel leakage from
hose connection in
fuel tank.
101) Disconnect fuel return hose from throttle body and
connect new return hose to it.
2) Insert the other end of new return hose into
approved gasoline container.
3) Check again if specified pressure is retained.
While doing so, does fuel come out of return hose?Faulty fuel pressure
regulator.Fuel leakage from
injector,
Fuel leakage from
between injector
and throttle body,
Faulty fuel pump
(faulty check valve
in fuel pump) or
Fuel leakage from
fuel pressure
regulator
diaphragm.
Page 153 of 557

A/C
amplifier(A / C ON output signal)
(A / C input signal)
6-102 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
TABLE B-4 A / C SIGNAL CIRCUITS CHECK (VEHICLE WITH A / C)
INSPECTION
STEPACTIONYESNO
1Check A / C (Input) Signal Circuit.
1) Check voltage at terminal C03-19.
While engine running and A / C switch
and / or heater blower switch OFF
(A / C is not operating) : 10 – 14 V
While engine running and both A / C
switch and heater blower switch ON
(A / C is operating) : About 0 V
Are check results as specified?Go to Step 2.“Bl / R” wire open or
short.
Poor C03-19
connection.
Poor A / C amplifier
coupler connection
or faulty A / C
system.
2Check A / C ON (Output) Signal Circuit.
1) Check voltage at terminal C03-17.
While engine running and A / C switch
and / or heater blower switch OFF
(A / C is not operating) : About 0 V
While engine running at idle speed
and both A / C switch and heater blower
switch ON (A / C is operating) : 10 – 14 V
Are check results as specified?A / C control signal
circuits are in good
condition.“Lg / R” wire open or
short.
Poor performance of
ECT sensor, TP
sensor.
Engine start signal
inputted or
Poor C03-17
connection.
If none of the above
exists, substitute a
known-good ECM
(PCM) and recheck.
Page 154 of 557
Power steering
pressure
switch
ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-103
TABLE B-5 POWER STEERING PRESSURE (PSP) SWITCH SIGNAL CIRCUIT
CHECK (IF EQUIPPED)
INSPECTION
STEPACTIONYESNO
1Check PSP Switch Signal Circuit.
1) Connect SUZUKI scan tool to DLC with ignition
switch OFF.
2) Start engine and select “DATA LIST” mode on
scan tool.
3) Check PSP switch signal under following each
condition. See Fig. 1.
Engine running and steering
wheel at straight-ahead position : OFF
Engine running and steering wheel
turned to the right on left as far as it stops : ON
Is check result satisfactory?PSP switch signal
circuit is in good
condition.“Bl / W” circuit open or
short, PSP switch
malfunction or power
steering system
malfunction.
Fig. 1 for Step 1
Page 155 of 557
6-104 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
09931-76011
SUZUKI scan tool (Tech 1 A) kit1. Storage case
2. Operator’s manual
3. Tech 1 A
4. DLC cable (14 / 26 pin,
09931-76040)
5. Test lead / probe
6. Power source cable
7. DLC cable adaptor
8. Self-test adaptor-1. Pressure gauge
09912-58441
-2. Pressure hose
09912-58431
-3. 3-way joint & hose
09912-58490
Mass storage cartridge09931-76030
16 / 14 pin DLC cable
SPECIAL TOOL
Page 156 of 557
ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G13) 6-1
SECTION 6
ENGINE GENERAL INFORMATION
AND DIAGNOSIS
(TBI FOR G13)
NOTE:
For the details of this section, refer to same section of the Service Manual mentioned in the FOREWORD
of this manual.