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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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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
A/C CONDENSER FAN (A/C CONDENSER FAN RELAY, ON / OFF)
ON : Command for condenser fan relay operation being output.
OFF : Command for relay operation not being output.
ELECTRIC LOAD (ON / OFF)
ON : Headlight, small light, heater fan or rear window defogger ON signal inputted.
OFF : Above electric loads all turned OFF.
A/C SWITCH (ON / OFF)
ON : Command for A/C operation being output from ECM to A/C amplifier.
OFF : Command for A/C operation not being output.
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ECM TERMINAL VOLTAGE VALUES TABLE
For TYPE A (See NOTE)
NOTE:
Type A is other than follows.
Type B is left hand steering vehicle equipped with fasten seat belt light and EGR valve or right hand
steering vehicle equipped with fasten seat belt light and immobilizer control system.
TERMINAL
NO.CIRCUIT NORMAL
VOLTAGECONDITION
E191Ground––
2Ground––
3Ground––
4 EVAP canister purge valve 10 – 14 V Ignition switch ON
5Power steering pressure switch
(if equipped)0 – 1.3 VWhile engine running at idle speed, turn
steering wheel to right or left as far as it
stops
10 – 14 V Ignition switch ON
6 Idle air control valve 0 – 13 VAt specified idle speed after engine
warmed up
7 Heater of HO2S-1 10 – 14 V Ignition switch ON
8 Fuel injector NO.4 10 – 14 V Ignition switch ON
9 Fuel injector NO.1 10 – 14 V Ignition switch ON
10 Sensor ground––
11 Camshaft position sensor0 – 0.8 V and
4 – 6 VIgnition switch ON
12–– –
13Heater oxygen sensor-1 Refer to DTC P0130 diag. flow table
CO adjusting resistor (w/o HO2S) 0 – 5 V Ignition switch ON position
14
Engine coolant temp. sensor 0.55 - 0.95 VIgnition switch ON
Engine coolant temp. : 80 °C (176 °F)
15
Intake air temp. sensor 2.0 – 2.7 VIgnition switch ON
Intake air temp. : 20 °C (68 °F)
16 Throttle opening signal0.2 – 1.0 VIgnition switch ON position and throttle
valve at idle position
2.8 – 4.8 VIgnition switch ON position and throttle
valve fully open
17EGR valve (stepper motor coil 3, if
equipped)10 – 14 VIgnition switch ON position leaving engine
OFF
18EGR valve (stepper motor coil 1, if
equipped)10 – 14 VIgnition switch ON position leaving engine
OFF
19 Ignition coil #2––
20 Ignition coil #1––
21 Fuel injector NO.2 10 – 14 V Ignition switch ON
22 Power source for sensors 4.75 – 5.25 V Ignition switch ON
23 Crankshaft position sensor0 – 0.8 or
4 – 5 VIgnition switch ON position
24–– –
25 Knock sensor About 2.5 VAt specified idle speed after engine
warmed up
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For TYPE B (See NOTE)
E1814Diag. Switch terminal (without
immobilizer indicator lamp)4 – 5 V Ignition switch ON
15Test switch terminal (without immo-
bilizer indicator lamp)4 – 5 V Ignition switch ON
16 A/C (input) signal10 – 14 VIgnition switch ON
A/C switch OFF
0 – 2 VIgnition switch ON
A/C switch ON
17 Lighting switch10 – 14 V Lighting switch ON
0 – 1.3 V Lighting switch OFF
18A/C condenser fan motor relay
(if equipped)0 – 1.0 V A/C is operating
10 – 14 V A/C is not operating
19 Fuel pump relay0 – 1 V For 2 seconds after ignition switch ON
10 – 14 V After the above time
20 Sensor ground––
21Throttle opening signal for
TCM (A/T)Indication
deflection
repeated
0 V and
10 – 14 VIgnition switch ON
22Fuel level sensor (gauge)
(with immobilizer indicator lamp)0 – 2 VIgnition switch ON
Fuel tank fully filled
4.5 – 7.5 VIgnition switch ON
Fuel tank emptied
23–– –
24 Heater blower switch0 – 2.0 VIgnition switch ON and heater blower
switch ON
10 – 14 VIgnition switch ON and heater blower
switch OFF TERMINAL
NO.CIRCUIT NORMAL
VOLTAGECONDITION
NOTE:
See NOTE in “ECM TERMINAL VOLTAGE VALUES TABLE” for applicable model.
TERMINAL
NO.CIRCUIT NORMAL
VOLTAGECONDITION
E181 A/C compressor clutch 0 V Ignition switch ON
2–– –
3–– –
4–– –
5 Power source 10 – 14 V Ignition switch ON
6 Power source 10 – 14 V Ignition switch ON
7 Power source for buck-up 10 – 14 V Ignition switch ON and OFF
8Immobilizer indicator lamp
(with immobilizer indicator lamp)10 – 14 V Engine running
0 – 1.0 V Ignition switch ON leaving engine OFF
Duty output terminal (without
immobilizer indicator lamp)0 – 1.0 V Ignition switch ON
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For TYPE A (See NOTE)
E189 Ignition switch 10 – 14 V Ignition switch ON
10 Main relay10 – 14 V Ignition switch OFF
0.4 – 1.5 V Ignition switch ON
11 Ignition switch 10 – 14 V Ignition switch ON
12 Rear defogger switch (if equipped)10 – 14 VIgnition switch ON and rear defogger
switch ON
0 – 1.3 VIgnition switch ON and rear defogger
switch OFF
13–– –
14Diag. Switch terminal (without
immobilizer indicator lamp)4 – 5 V Ignition switch ON
15Test switch terminal (without immo-
bilizer indicator lamp)4 – 5 V Ignition switch ON
16 A/C (input) signal10 – 14 VIgnition switch ON
A/C switch OFF
0 – 2 VIgnition switch ON
A/C switch ON
17 Lighting switch10 – 14 V Lighting switch ON
0 – 1.3 V Lighting switch OFF
18A/C condenser fan motor relay
(if equipped)0 – 1.0 V A/C is operating
10 – 14 V A/C is not operating
19 Fuel pump relay0 – 1 V For 2 seconds after ignition switch ON
10 – 14 V After the above time
20 Engine start signal 6 – 14 V While engine cranking
21 Stop lamp switch0 VIgnition switch ON
Stop lamp switch OFF
10 – 14 VIgnition switch ON
Stop lamp switch ON
22 Vehicle speed sensordeflect
between
0 – 1.6 and
4 – 14 VIgnition switch ON and rear right wheel
turned slowly with rear left wheel locked
23–– –
24–– – TERMINAL
NO.CIRCUIT NORMAL
VOLTAGECONDITION
NOTE:
See NOTE in “ECM TERMINAL VOLTAGE VALUES TABLE” for applicable model.
TERMINAL
NO.CIRCUIT NORMAL
VOLTAGECONDITION
E171–– –
2 R-range signal (A/T)10 – 14 VIgnition switch ON and shift select switch
in R range
0 – 1.3 VIgnition switch ON and shift select switch
in other than R range
3 Blank––
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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-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.
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DTC P0300 Random Misfire Detected (Misfire Detected at 2 or More Cylinders)
DTC P0301 Cylinder 1 Misfire Detected
DTC P0302 Cylinder 2 Misfire Detected
DTC P0303 Cylinder 3 Misfire Detected
DTC P0304 Cylinder 4 Misfire Detected
CIRCUIT DESCRIPTION
ECM monitors crankshaft revolution speed and engine speed via the crankshaft position sensor and cylinder No.
via the camshaft position sensor. Then it calculates the change in the crankshaft revolution speed and from how
many times such change occurred in every 200 or 1000 engine revolutions, it detects occurrence of misfire.
When ECM detects a misfire (misfire rate per 200 revolutions) which can cause overheat and damage to the
three way catalytic converter, it makes the malfunction indicator lamp (MIL) flash as long as misfire occurs at
that rate.
After that, however, when the misfire rate drops, MIL remains ON until it has been judged as normal 3 times
under the same driving conditions.
Also, when ECM detects a misfire (misfire rate per 1000 revolutions) which will not cause damage to three way
catalytic converter but can cause exhaust emission to be deteriorated, it makes MIL light according to the 2 driv-
ing cycle detection logic.
1. Ignition coil assembly (for No.1 and No.4 cylinder)
2. Ignition coil assembly (for No.2 and No.3 cylinder)
3. Fuel injector
4. CKP sensor
5. CMP sensor