Page 197 of 557

Main
fuseIgnition
switch
Main
relay Malfunction indicator lamp in combination meter
Relay
box
Fuse box
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-41
TABLE A-3 ECM (PCM) POWER AND GROUND CIRCUIT CHECK – MIL
DOESN’T LIGHT AT IGNITION SWITCH ON AND ENGINE DOESN’T
START THOUGH IT IS CRANKED UP
CIRCUIT DESCRIPTION
When the ignition switch tuned ON, the main relay turns ON (the contact point closes) and the main power is sup-
plied to ECM (PCM).
INSPECTION
STEPACTIONYESNO
1Main Relay Operating Sound Check
Is operating sound of main relay heard at ignition switch ON?Go to Step 5.Go to Step 2.
2Main Relay Check
1) Turn OFF ignition switch and remove main relay (1).
2) Check for proper connection to main relay (1) at terminal
3 and 4.
3) Check resistance between each two terminals. See Fig. 1
and 2.
Between terminals 1 and 2: Infinity
Between terminals 3 and 4: 100 – 150 Ω
4) Check that there is continuity between terminals 1 and 2
when battery is connected to terminals 3 and 4. See Fig. 3.
Is main relay in good condition?Go to Step 3.Replace main
relay.
3Fuse Check
Is main “FI” fuse in good condition?Go to Step 4.Check for short in
circuits connected
to this fuse.
4ECM (PCM) Power Circuit Check
1) Turn OFF ignition switch, disconnect connectors from ECM
(PCM) and install main relay.
2) Check for proper connection to ECM (PCM) at terminals
C03-6, C02-10, C02-5 and C02-6.
3) If OK, then measure voltage between terminal C03-6 and
ground, C02-10 and ground with ignition switch ON.
Is each voltage 10 – 14 V?Go to Step 5.“B/W”, “W/R” or
“Gr” circuit open.
Page 198 of 557
6-1-42 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
Fig. 1 for Step 2 Fig. 2 for Step 2 Fig. 3 for Step 2
STEPACTIONYESNO
5ECM (PCM) Power Circuit Check
1) Using service wire, ground terminal C02-10 and
measure voltage between terminal C02-5 / 6 and
ground at ignition switch ON.
Is it 10 – 14 V?Check ground circuits
“B/Y” and “B” for
open.
If OK, then substitute a
known-good ECM
(PCM) and recheck.Go to Step 6.
6Is operating sound of main relay heard in Step 1?Go to Step 7.“W/R” or “R/B” wire
open.
7Main Relay Check
1) Check main relay according to procedure in
Step 2.
Is main relay in good condition?“W/R” or “R/B” wire
open.Replace main relay.
Page 199 of 557
MAP
sensor
To other sensorsTo TP sensor
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-43
DTC P0105 MANIFOLD ABSOLUTE PRESSURE (MAP) CIRCUIT
MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
MAP: 4.9 kpa, 37 mmHg or less
(Low pressure – High vacuums – Low voltage)
MAP: 114.7 kpa, 860 mmHg or more
(High pressure – Low vacuums – High voltage)“G” circuit open
“P” circuit open or shorted to ground
“G” circuit open or shorted to ground
MAP sensor malfunction
ECM (PCM) malfunction
NOTE:
When DTC P0120 is indicated together, it is possible that “P” circuit is open.
DTC CONFIRMATION PROCEDURE
1) Clear DTC, start engine and keep it at idle for 1 min.
2) Select “DTC” mode on scan tool and check DTC.
Page 200 of 557

6-1-44 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
MAP Sensor Individual Check
1) Disconnect coupler from MAP sensor (1).
2) Remove MAP sensor (1).
3) Arrange 3 new 1.5 V batteries (2) in series (check that total volt-
age is 4.5 – 5.0 V) and connect its positive terminal to “Vin” termi-
nal of sensor and negative terminal to “Ground” terminal. Then
check voltage between “Vout” and “Ground”.
Also, check if voltage reduces when vacuum is applied up to 400
mmHg by using vacuum pump (3).
Output voltage (Vin voltage 4.5 – 5.5 V, ambient temp. 20 –
30C, 68 – 86F)
ALTITUDE
BAROMETRICOUTPUT
(Reference)PRESSUREVOLTAGE
(ft)(m)(mmHg)(kPa)(V)
0
0
760
100
3343
2 000
610
707
94
3.3 – 4.3
2 001
611
Under 70794
3041
5 000
1 524over 634
85
3.0 – 4.1
5 001
1 525
Under 63485
2737
8 000
2 438over 567
76
2.7 – 3.7
8 001
2 439
Under 56776
25–33
10 000
3 048over 526
70
2.5 – 3.3
If check result is not satisfactory, replace MAP sensor (1).
4) Install MAP sensor (1) securely.
5) Connect MAP sensor (1) coupler securely.
Page 201 of 557

ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-45
Fig. 1 for Step 2 Fig. 2 for Step 3
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE”
performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Check MAP Sensor and Its Circuit.
1) Connect scan tool to DLC with ignition
switch OFF.
2) Turn ignition switch ON.
3) Check intake manifold pressure.
See Fig. 1.
Is it 114.7 kPa or more or 4.9 kPa or less?Go to Step 3.Intermittent trouble.
Check for intermittent
referring to
“INTERMITTENT AND
POOR CONNECTION” in
Section 0A.
3Check Wire Harness.
1) Disconnect MAP sensor connector with
ignition switch OFF.
2) Check for proper connection of MAP
sensor at “Gr” and “G” wire terminals.
3) If OK, then with ignition switch ON, check
voltage at each of “P” and “Gr” wire
terminals. See Fig. 2.
Is voltage about 4 – 6 V at each terminal?Go to Step 4.“P” wire open or shorted to
ground circuit or shorted to
power circuit, “Gr” wire
open or shorted to ground,
poor C03-5 connection or
C01-22 connection.
If wire and connection are
OK, confirm that MAP
sensor is normal and then
substitute a known-good
ECM (PCM) and recheck.
NOTE: When battery
voltage is applied to
“P” wire, it is possible
that MAP sensor is also
faulty.
4Check MAP sensor according to “MAP
Sensor Individual Check” below.
Is it in good condition?“P” wire shorted to “Gr”
wire, “G” wire open,
poor C01-10 connection.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.Replace MAP sensor.
Page 202 of 557
6-1-46 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
IAT sensor
To other sensors
DTC P0110 INTAKE AIR TEMP. (IAT) CIRCUIT MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
Low intake air temperature (High voltage-High resistance)
High intake air temperature (Low voltage-Low resistance)“Gr / R” circuit open or shorted to power
“G” circuit open
IAT sensor malfunction
ECM (PCM) malfunction
NOTE:
When DTC P0115 and P0120 are indicated together, it is possible that “G” circuit is open.
Before inspecting, be sure to check that ambient temperature is higher than –40C (–40F).
DTC CONFIRMATION PROCEDURE
1) Clear DTC, start engine and keep it at idle for 1 min.
2) Select “DTC” mode no scan tool and check DTC.
Page 203 of 557

ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-47
Fig. 1 for Step 2 Fig. 2 for Step 3 Fig. 3 for Step 4
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Check IAT Sensor and Its Circuit.
1) Connect scan tool to DLC with ignition switch
OFF.
2) Turn ignition switch ON.
3) Check intake air temp. displayed on scan tool.
See Fig. 1.
Is –40C (–40F) or 119C (246F) indicated?Go to Step 3.Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection”
in Section 0A.
3Check Wire Harness.
1) Disconnect IAT sensor connector with ignition
switch OFF.
2) Check for proper connection to IAT sensor at
“Gr / R” and “G” wire terminals.
3) If OK, then with ignition switch ON, is voltage
applied to “Gr / R” wire terminal about 4 – 6 V?
See Fig. 2.Go to Step 5.“Gr / R” wire open or
shorted to power, or
poor C01-15
connection.
If wire and connection
are OK, substitute a
known-good ECM
(PCM) and recheck.
4Does scan tool indicate –40C (–40F) at Step 2.Go to Step 6.Go to Step 5.
5Check Wire Harness
1) Check intake air temp. displayed on scan tool
with ignition switch ON.
Is –40C (–40F) indicated?Replace IAT sensor.“Gr / R” wire shorted to
ground.
If wire is OK, substitute
a known-good ECM
(PCM) and recheck.
6Check Wire Harness.
1) Using service wire, connect IAT sensor
connector terminals.
2) Check intake air temp. displayed on scan tool
with ignition switch ON. See Fig. 3.
Is 119C (246F) indicated?Replace IAT sensor.“Gr / R” wire open or
poor C01-10
connection.
If wire and connection
are OK, substitute a
known-good ECM
(PCM) and recheck.
Page 204 of 557
6-1-48 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
To combination
(ECT) meterTo other sensors
NOTE:
Before inspecting, be sure to check that cool-
ant temp. meter in combination meter indi-
cates normal operating temperature (Engine
is not overheating).
DTC P0115 ENGINE COOLANT TEMPERATURE (ECT) CIRCUIT
MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
Low engine coolant temperature (High voltage-High resistance)
High engine coolant temperature (Low voltage-Low resistance)“Lg / R” circuit open or shorted to power
“G” circuit open
ECT sensor malfunction
ECM (PCM) malfunction
DTC CONFIRMATION PROCEDURE
1) Clear DTC, start engine and keep it at idle for 1 min.
2) Select “DTC” mode on scan tool and check DTC.