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Scan Tool Data
As the data values given below are standard values estimated on the basis of values obtained from the normally
operating vehicles by using a scan tool, use them as reference values. Even when the vehicle is in good condi-
tion, there may be cases where the checked value does not fall within each specified data range. Therefore,
judgment as abnormal should not be made by checking with these data alone.
Also, conditions in the below table that can be checked by the scan tool are those detected by ECM and output
from ECM as commands and there may be cases where the engine or actuator is not operating (in the condi-
tion) as indicated by the scan tool. Be sure to use the timing light to check the ignition timing.
NOTE:
With the generic scan tool, only star (
✱
✱✱ ✱) marked data in the table below can be read.
The triangle (
∆
∆∆ ∆) marked data in the table below can not be read for vehicle without immobilizer indi-
cator lamp at combination meter.
When checking the data with the engine running at idle or racing, be sure to shift M/T gear to the
neutral gear position and A/T gear to the “Park” position and pull the parking brake fully. Also, if
nothing or “no load” is indicated, turn OFF A/C, all electric loads, P/S and all the other necessary
switches.
SCAN TOOL DATA CONDITION REFERENCE VALUES
✱
✱✱ ✱FUEL SYSTEM B1 (FUEL
SYSTEM STATUS)At specified idle speed after warming up CLOSED (closed loop)
✱
✱✱ ✱
CALC LOAD
(CALCULATED LOAD
VALUE)At specified idle speed with no load after
warming up3 – 9 %
At 2500 r/min with no load after warming up 12 – 17 %
✱
✱✱ ✱COOLANT TEMP.
(ENGINE COOLANT
TEMP.)At specified idle speed after warming up 80 – 100 °C, 176 – 212 °F
✱
✱✱ ✱SHORT FT B1 (SHORT
TERM FUEL TRIM)At specified idle speed after warming up– 20 – +20 %
✱
✱✱ ✱LONG FT B1 (LONG TERM
FUEL TRIM)At specified idle speed after warming up– 15 – +15 %
✱
✱✱ ✱MAP (INTAKE MANIFOLD
ABSOLUTE PRESSURE)At specified idle speed with no load after30 – 37 kPa,
220 – 340 mmHg
✱
✱✱ ✱
ENGINE SPEED At idling with no load after warming upDesired idle speed
±50 r/min
✱
✱✱ ✱VEHICLE SPEED At stop 0 km/h, 0 MPH
✱
✱✱ ✱IGNITION ADVANCE
(IGNITION TIMING
ADVANCE FOR NO.1 CYL-
INDER)At specified idle speed with no load after
warming up5 – 16° BTDC
✱
✱✱ ✱
INTAKE AIR TEMP. At specified idle speed after warming upAmbient temp. :
+15 °C (59 °F)
–5 °C (23 °F)
✱
✱✱ ✱MAF (MASS AIR FLOW
RATE)At specified idle speed with no load after
warming up1 – 4 gm/sec
✱
✱✱ ✱
THROTTLE POS
(THROTTLE POSITION)Ignition switch
ON / engine
stoppedThrottle valve fully closed 7 – 18 %
Throttle valve fully open 70 – 90 %
✱
✱✱ ✱O2S B1 S1 (HEATED OXY-
GEN SENSOR-1)At specified idle speed after warming up 0.01 – 0.95 V
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Scan tool data definitions
FUEL SYSTEM (FUEL SYSTEM STATUS)
Air / fuel ratio feedback loop status displayed as either open or closed loop. Open indicates that ECM ignores
feedback from the exhaust oxygen sensor.
Closed indicates final injection duration is corrected for oxygen sensor feedback.
CALC LOAD (CALCULATED LOAD VALUE, %)
Engine load displayed as a percentage of maximum possible load. Value is calculated mathematically using the
formula : actual (current) intake air volume ÷ maximum possible intake air volume x 100%.
COOLANT TEMP. (ENGINE COOLANT TEMPERATURE, °C, °F)
It is detected by engine coolant temp. sensor
SHORT FT B1 (SHORT TERM FUEL TRIM, %)
Short term fuel trim value represents short term corrections to the air / fuel mixture computation. A value of 0
indicates no correction, a value greater than 0 means an enrichment correction, and a value less than 0 implies
an enleanment correction.
LONG FT B1 (LONG TERM FUEL TRIM, %)
Long term fuel trim Value represents long term corrections to the air / fuel mixture computation. A value of 0 indi-
cates no correction, a value greater than 0 means an enrichment correction, and a value less than 0 implies an
enleanment correction.
MAP (INTAKE MANIFOLD ABSOLUTE PRESSURE, kPa, inHg)
It is detected by manifold absolute pressure sensor and used (among other things) to compute engine load.
ENGINE SPEED (rpm)
It is computed by reference pulses from crankshaft position sensor.
VEHICLE SPEED (km/h, MPH)
It is computed based on pulse signals from vehicle speed sensor.
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.BRAKE SWIgnition switch
ONBrake pedal is depressing ON
Brake pedal is releasing OFF
BLOWER FANIgnition switch
ONBlower fan switch ON ON
Blower fan switch OFF OFF
A/C MAG CLUTCHIgnition switch
ONA/C operating ON
A/C not operating OFF SCAN TOOL DATA CONDITION REFERENCE VALUES
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Inspection of ECM and Its Circuits
ECM and its circuits can be checked at ECM wiring connectors by
measuring voltage and resistance.
VOLTAGE CHECK
1) Remove ECM from body referring to Section 6E.
2) Check voltage at each terminal of connectors connected.CAUTION:
ECM cannot be checked by itself. It is strictly prohibited
to connect voltmeter or ohmmeter to ECM with connector
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. ECM
2. ECM connectors (Viewed from harness side)
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Resistance Check
1) Disconnect ECM couplers (1) from ECM with ignition switch
OFF.
2) Check resistance between each terminal of couplers discon-
nected. CAUTION:
Never touch terminals of ECM itself or connect voltmeter
or ohmmeter (2).
CAUTION:
Be sure to connect ohmmeter probe from wire harness
side of coupler.
Be sure to turn OFF ignition switch for this check.
Resistance in table below represents that when parts
temperature is 20 °C (68 °F).
1. ECM coupler disconnected
2. Ohmmeter
TERMINALS CIRCUIT STANDARD RESISTANCE
E19-7 to E17-9
(For TYPE A) (See NOTE)HO2S-1 heater 5 – 6.4 Ω
E19-7 to E18-11
(For TYPE B) (See NOTE)
E18-4 to E17-9
(For TYPE A) (See NOTE)HO2S-2 heater 11.7 – 14.3 Ω
E19-9 to E19-2 No.1 injector 12.0 – 13.0 Ω
E19-21 to E19-2 No.2 injector 12.0 – 13.0 Ω
E19-31 to E19-2 No.3 injector 12.0 – 13.0 Ω
E19-8 to E19-2 No.4 injector 12.0 – 13.0 Ω
E19-28 to E19-2 EGR valve (stepper motor coil 4) 20 – 24 Ω
E19-17 to E19-2 EGR valve (stepper motor coil 3) 20 – 24 Ω
E19-29 to E19-2 EGR valve (stepper motor coil 2) 20 – 24 Ω
E19-18 to E19-2 EGR valve (stepper motor coil 1) 20 – 24 Ω
E19-4 to E19-2 EVAP canister purge valve 30 – 34 Ω
E18-19 to E17-9 (For
TYPE A) (See NOTE)Fuel pump relay 70 – 110 Ω
E18-19 to E18-11 (For
TYPE B) (See NOTE)
E18-1 to Body ground A/C compressor clutch 3 – 4.5 Ω
E18-18 to E19-2 A/C condenser fan control relay 70 – 110 Ω
E18-10 to E18-7 Main relay 70 – 110 Ω
E19-1 to Body ground Ground Continuity
E19-2 to Body ground Ground Continuity
E19-3 to Body ground Ground Continuity
NOTE:
For TYPE A and TYPE B, refer to the NOTE in “ECM Terminal Voltage Values Table” for applicable
model.
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Table A-1 Malfunction Indicator Lamp Circuit Check - Lamp Does Not Come
“ON” at Ignition Switch ON (But Engine at Stop)
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. Main fuse 4. Main relay 7.“IG” fuse [A] : Case of TYPE A is shown
(See NOTE)
2. Ignition switch 5. Malfunction indicator lamp in
combination meter8.“IG COIL METER” fuse [B] : Case of TYPE B is shown
(See NOTE)
3. Fuse box 6.“FI” fuse
NOTE:
For TYPE A and TYPE B, refer to the NOTE in “ECM Terminal 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 combina-
tion meter comes ON?Go to Step 2.“IG” fuse blown, main fuse
blown, ignition switch mal-
function, “B/W” circuit
between “IG” fuse and
combination meter or
poor coupler connection
at combination meter.
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Table A-2 Malfunction Indicator Lamp Circuit Check - Lamp Remains “ON”
after Engine Starts
WIRING DIAGRAM / CIRCUIT DESCRIPTION
Refer to table A-1.
INSPECTION
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 8G.
3 MIL Circuit Check
1) Turn ignition switch OFF and disconnect
connectors from ECM.
2) Check for proper connection to ECM at ter-
minal E18-2 (Case of TYPE A) (See NOTE)
or E17-9 (Case of TYPE B) (See NOTE).
3) If OK, then using service wire, ground termi-
nal E18-2 (Case of TYPE A) (See NOTE) or
E17-9 (Case of TYPE B) (See NOTE) in
connector disconnected.
Does MIL turn on at ignition switch ON?Substitute a known-good
ECM and recheck.Bulb burned out, “V/Y”
wire circuit open or “P”
wire shorted to ground. Step Action Yes No
Step Action Yes No
1 Diagnostic Trouble Code (DTC) check
1) Check DTC referring to DTC CHECK sec-
tion.
Is there any DTC(s)?Go to Step 2 of “Engine
Diag. Flow Table”.Go to Step 2.
2DTC check
1) Start engine and recheck DTC while engine
running.
Is there any DTC(s)?Go to Step 3.
3 MIL Circuit check
1) Turn OFF ignition switch.
2) Disconnect connectors from ECM.
Does MIL turn ON at ignition switch ON?“V/Y” wire circuit shorted
to ground.Substitute a known-good
ECM and recheck.
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Table A-3 Malfunction Indicator Lamp Circuit Check - Mil Flashes at Ignition
Switch ON
WIRING DIAGRAM / CIRCUIT DESCRIPTION
Refer to table A-1.
INSPECTION
Table A-4 Malfunction Indicator Lamp Circuit Check - MIL Does Not Flash, Just
Remains ON or Just Remains OFF Even with Grounding Diagnosis Switch
Terminal
WIRING DIAGRAM / CIRCUIT DESCRIPTION
Refer to table A-1.
INSPECTION
Step Action Yes No
1 MIL flashing pattern check :
1) With the ignition switch ON position, check
MIL flashing pattern.
Does MIL flashing pattern indicate DTC (diag-
nostic trouble code)?Go to Step 2. Go to “Diagnosis” in Sec-
tion 8G.
2 Diagnosis switch terminal check :
1) With the ignition switch ON position, check
voltage between E18-14 terminal of ECM
coupler and ground.
Is voltage 4 – 5 V?Substitute a known-good
ECM and recheck.“W/Bl” wire (diagnosis
switch terminal) shorted
to ground circuit.
If OK, substitute a known-
good ECM and recheck.
Step Action Yes No
1 MIL flashing pattern check :
1) With grounding diagnosis switch terminal
and turn the ignition switch ON position,
check voltage between E18-14 terminal of
ECM connector and ground.
Is voltage 0 – 1 V?Go to Step 2.“W/Bl” wire (diagnosis
switch terminal), “B” wire
of monitor connector
open.
If OK, substitute a known-
good ECM and recheck.
2 Test switch terminal circuit check :
1) With the ignition switch ON position, check
voltage between E18-15 terminal of ECM
connector and ground.
Is voltage 4 – 5 V?Substitute a known-good
ECM and recheck.“P” wire (test switch termi-
nal) shorted to ground cir-
cuit.
If OK, substitute a known-
good ECM and recheck.
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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
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.
INSPECTION
1. Main fuse 4. Main relay 7.“IG” fuse [A] : Case of TYPE A is shown (See
NOTE)
2. Ignition switch 5. Malfunction indicator lamp in
combination meter8.“IG COIL METER” fuse [B] : Case of TYPE B is shown (See
NOTE)
3. Fuse box 6.“FI” fuse
NOTE:
For TYPE A and TYPE B, refer to the NOTE in “ECM Terminal Voltage Values Table” for applicable
model.
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) at terminal 3 and 4.
3) Check resistance between each two terminals. See Fig. 1 and 2.
Main relay resistance
Between terminals A and B : Infinity
Between terminals C and D : 70 – 110
Ω
Ω Ω Ω (at 20 °C, 68 °F)
4) Check that there is continuity between terminals 1 and 2 when bat-
tery is connected to terminals 3 and 4. See Fig. 3.
Is main relay in good condition?Go to Step 3. Replace main
relay.