6-30 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
SCAN TOOL DATACONDITIONNORMAL CONDITION /
REFERENCE VALUES
DESIRED IDLEAt idling with no load after warming up, M / T850 r / min(DESIRED IDLE SPEED)
gg,
at neutral, A / T at “P” range850 r / min
TP SENSOR VOLT
(THROTTLE POSITIONIgnition switch
ON / engine
Throttle valve fully closedMore than 0.2 V(
SENSOR OUTPUT
VOLTAGE)ON / engine
stoppedThrottle valve fully openLess than 4.8 V
INJ PULSE WIDTH
(FUEL INJECTIONAt specified idle speed with no load after
warming up0.8 – 2.3 msec.(
PULSE WIDTH)At 2500 r / min with no load after warming up0.8 – 2.3 msec.
IAC FLOW DUTY (IDLE
AIR CONTROL FLOW
DUTY)
At idling with no load after warming up20 – 40%
TOTAL FUEL TRIMAt specified idle speed after warming up–35 – +35%
BATTERY VOLTAGEIgnition switch ON / engine stop10 – 14 V
CANIST PRG DUTY
(EVAP CANISTER
PURGE FLOW DUTY)
At specified idle speed after warming up0 – 100%
CLOSED THROT POS
(CLOSED THROTTLEThrottle valve at idle positionON(CLOSED THROTTLE
POSITION)Throttle valve opens larger than idle positionOFF
FUEL CUTWhen engine is at fuel cut conditionONFUEL CUTOther than fuel cut conditionOFF
RAD FAN
(RADIATOR FANIgnition switch
ON
Engine coolant temp.:
Lower than 92.5C
(199F)
OFF
(
CONTROL RELAY)ONEngine coolant temp.:
97.5C (208F) or higherON
ELECTRIC LOAD
Ignition switch ON / Headlight, small light,
heater fan and rear window defogger all
turned OFF
OFF
ELECTRIC LOADIgnition switch ON / Headlight, small light,
heater fan or rear window defogger turned
ON
ON
A / C SWITCH
Engine running after warming up, A / C not
operatingOFF
A/C SWITCHEngine running after warming up, A / C
operatingON
PSP SWITCH
Engine running at idle speed and steering wheel
at straight-ahead position.OFF
(if equipped).Engine running at idle speed and steering wheel
turned to the right or left as far as it stops.ON
FUEL TANK LEVEL––––––––––––0 – 100%
BAROMETRIC PRESS––––––––––––Display the barometric pressure
FUEL PUMP
Within 3 seconds after ignition switch ON or
engine runningON
Engine stop at ignition switch ON.OFF
6-32 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
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 (PCM)
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 us-
ing 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 val-
ue 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 correc-
tions 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 im-
plies 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 (PCM). 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 sen-
sor, 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 ex-
haust manifold (pre-catalyst).
OXYGEN SENSOR B1 S2
(HEATED OXYGEN SENSOR-2, V)
It indicates output voltage of HO2S-2 installed on ex-
haust pipe (post-catalyst). It is used to detect catalyst
deterioration.
DESIRED IDLE (DESIRED IDLE SPEED, rpm)
The Desired Idle Speed is an ECM (PCM) internal pa-
rameter which indicates the ECM (PCM) 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
(PCM) (but injector drive time of NO.1 cylinder for
multiport fuel injection).
IAC FLOW DUTY (IDLE AIR (SPEED) CONTROL
DUTY, %)
This parameter indicates opening of the throttle valve
in terms of percentage to opening controllable by the
ISC actuator.
TOTAL FUEL TRIM (%)
The value of Total Fuel Trim is obtained by putting val-
ues 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 stoichiomet-
rical.
BATTERY VOLTAGE (V)
This parameter indicates battery positive voltage in-
putted from main relay to ECM (PCM).
ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-33
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 ful-
ly 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
RAD FAN
(RADIATOR FAN CONTROL RELAY, ON / OFF)
ON : Command for radiator fan control relay opera-
tion being output.
OFF : Command for relay operation not being out-
put.
ELECTRIC LOAD (ON / OFF)
ON : Headlight, small light, heater fan or rear win-
dow 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 (PCM) to A / C amplifier.
OFF : Command for A / C operation not being output.
FUEL TANK LEVEL (%)
This parameter indicates approximate fuel level in the
fuel tank. As the detectable range of the fuel level sen-
sor is set as 0 to 100%, however, with some models
whose fuel tank capacity is smaller, the indicated fuel
level may be only 70% even when the fuel tank is full.
PSP SWITCH (ON / OFF)
ON : PSP switch detects P / S operation (high PS
pressure).
OFF : PSP switch not detects P / S operation.
BAROMETRIC PRESS (kPa, inHg)
This parameter represents a measurement of baro-
metric air pressure and is used for altitude correction
of the fuel injection quantity and ISC actuator control.
FUEL PUMP (ON / OFF)
ON is displayed when the ECM (or PCM) activates the
fuel pump via the fuel pump relay switch.
VSS (A / T) (km / h, MPH)
If is computed by using pulse signals from vehicle
(output) speed sensor on automatic transmission.
TRANS RANGE (TRANSMISSION RANGE
SENSOR, P, R, N, D, 2 OR L)
It is indicated transmission range detected by trans-
mission range sensor.
SHIFT SOL 1-CON (SHIFT SOLENOID-1,
ON / OFF)
ON : ON command being output to shift solenoid-1
OFF : ON command not being output.
SHIFT SOL 2-CON (SHIFT SOLENOID-2,
ON / OFF)
ON : ON command being output to shift solenoid-2
OFF : ON command not being output.
SHIFT SOL 1-MON (SHIFT SOLENOID-1,
ON / OFF)
The monitor result of the shift solenoid-1 circuit is dis-
played.
ON : Electricity being passed to shift solenoid-1 or
circuit open.
OFF : Electricity not being passed or circuit short.
SHIFT SOL 2-MON (SHIFT SOLENOID-2,
ON / OFF)
The monitor result of the shift solenoid-2 circuit is dis-
played.
ON : Electricity being passed to shift solenoid-2 or
circuit open.
OFF : Electricity not being passed or circuit short.
THROT POS LEVEL (THROTTLE POSITION
LEVEL FOR A / T, “0”, “1”, “2”, “3”, “4”, “5”, “6”
or “7”)
This parameter indicates which level (zone) the
throttle valve opening is in. The throttle opening is di-
vided into 8 levels (zones) from “0” (about idle posi-
tion) to “7” (about full open) and signals are assigned
to each opening level (zone). ECM (PCM) control the
automatic gear change of the automatic transmission
by using these signals according to the signal from
the TP sensor.
GEAR POSITION
This parameter indicates the A / T gear position which
is computed on signals from the Transmission Range
Switch, VSS, TP Sensor, and so forth.
6-60 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
Usual driving: Driving at 30 – 40 mph, 50 – 60 km/h including short stop according to traffic signal. (under driving condition other than high-load,
high-engine speed, rapid accelerating and decelerating)1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11)and 50 mph
(80 km / h)
Above 20 mph
(32 km / h) Usual driving
DTC CONFIRMATION PROCEDURE
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester, on a level road.
1) Turn ignition switch OFF.
Clear DTC with ignition switch ON, check vehicle and environmental condition for:
–Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Ambient temp.: –10C, 14F or higher
–Intake air temp.: 70C, 158F or lower
–No exhaust gas leakage and loose connection
2) Warm up engine to normal operating temperature.
3) Drive vehicle under usual driving condition for 5 min. and check HO2S-2 output voltage and “short term fuel
trim” with “Data List” mode on scan tool, and write it down.
4) Stop vehicle (don’t turn ignition switch OFF).
5) Increase vehicle speed to higher than 20 mph, 32 km / h and then stop vehicle.
6) Repeat above steps 5) 4 times.
7) Increase vehicle speed to about 50 mph (80 km / h) in 3rd gear or 2 range.
8) Release accelerator pedal and with engine brake applied, keep vehicle coasting (fuel cut condition) for 10sec.
or more.
9) Stop vehicle (don’t turn ignition switch OFF) and run engine at idle for 2 min.
After this step 9), if “Oxygen Sensor Monitoring TEST COMPLETED” is displayed in “READINESS TESTS”
mode and DTC is not displayed in “DTC” mode, confirmation test is completed.
If “TEST NOT COMPLTD” is still being displayed, proceed to next step 10).
10) Drive vehicle under usual driving condition for 10 min. (or vehicle is at a stop and run engine at idle for 10 min.
or longer)
11) Stop vehicle (don’t turn ignition switch OFF). Confirm test results according to “Test Result Confirmation Flow
Table” in “DTC CONFIRMATION PROCEDURE” of DTC P0420.
6-64 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
Sensed
information
Exhaust
gasFuel
injector
A/F
mixtureSignal to decrease amount of fuel injection
Signal to increase amount of fuel injection
High voltage
Low voltage
INJECTORHEATED
OXYGEN
SENSOR-1
A / F mixture
becomes
richerOxygen
concentration
decreases
A / F mixture
becomes
leanerOxygen
concentration
increases ECM
(PCM)
ECM
(PCM)
Main
fuseIgnition switch“IG COIL METER”
Main relayTo other circuits
Injector resistor
To other
sensorFuel
injector
Heated oxygen sensor-1
HO2S-1
DTC P0171 FUEL SYSTEM TOO LEAN
DTC P0172 FUEL SYSTEM TOO RICH
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
When following condition occurs while engine running under
closed loop condition.
–Air / fuel ratio too lean
Total fuel trim (short and long terms added) is
more than 30%
or
–Air / fuel ratio too rich
(Total fuel trim is less than –30%)
2 driving cycle detection logic, continuous monitoring.Vacuum leaks (air drawn in).
Exhaust gas leakage.
Heated oxygen sensor-1 circuit
malfunction.
Fuel pressure out of specification.
Fuel injector malfunction (clogged or
leakage).
MAP sensor poor performance.
ECT sensor poor performance.
IAT sensor poor performance.
TP sensor poor performance.
EVAP control system malfunction.
PCV valve malfunction.
6-66 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE
DIAG. FLOW
TABLE”.
2Is there DTC(s) other than fuel system
(DTC P0171 / P0172)?Go to applicable
DTC Diag. Flow
Table.Go to Step 3.
3Check HO2S-1 Output Voltage.
1) Connect scan tool to DLC with ignition switch OFF.
2) Warm up engine to normal operating temperature and keep
it at 2000 r / min. for 60 sec.
3) Repeat racing engine (Repeat depressing accelerator pedal
5 to 6 times continuously and take foot off from pedal to
enrich and enlean A / F mixture). See Fig. 1.
Does HO2S-1 output voltage deflect between below 0.3 V and
over 0.6 V repeatedly?Go to Step 4.Go to DTC
P0130 Diag.
Flow Table
(HO2S-1 circuit
check).
4Check 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. See Fig. 2.
With fuel pump operating
and engine at stop : 160 – 210 kPa, 1.6 – 2.1 kg / cm
2,
22.7 – 29.9 psi.
At specified idle speed : 90 – 140 kPa, 0.9 – 1.4 kg / cm
2,
12.8 – 20.0 psi.
Is measured value as specified?
Go to Step 5.Go to Diag. Flow
Table B-3 Fuel
Pressure Check.
5Check Fuel Injectors and Circuit.
1) Turn ignition switch OFF and disconnect fuel injector
connector.
2) Check for proper connection to fuel injector at each terminals.
3) If OK, then check injector resistance. See Fig. 3.
Injector resistance: 0.5 – 1.5 Ω at 20C (68F)Go to Step 6.Check injector
circuit or replace
fuel injector.
4) Connect injector, connector.
5) Check that fuel is injected out in conical shape from fuel
injector when running engine.
6) Check injector for fuel leakage after engine stop.
Fuel leakage: Less than 1 drop / min.
Is check result satisfactory?
6Check EVAP Canister Purge Valve.
1) Disconnect purge hose (1) from EVAP canister.
2) Place finger against the end of disconnected hose.
3) Check that vacuum is not felt there when engine is cool and
running at idle. See Fig. 4.
Is vacuum felt?Check EVAP
control system
(See Section
6E1).Go to Step 7.
7Check intake manifold absolute pressure sensor for
performance (See DTC P0105 Diag. Flow Table).
Is it in good condition?Go to Step 8.Repair or
replace.
ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-69
Below
specified value DTC DETECTING CONDITION
POSSIBLE CAUSE
Engine under other than high revolution condition
Not on rough road
Engine speed changing rate
Manifold absolute
pressure changing rate
Throttle opening changing rate
Misfire rate per 200 or 1000 engine revolutions (how
much and how often crankshaft revolution speed
changes) is higher than specified valueEngine overheating
Vacuum leaks (air inhaling) from air intake system
Ignition system malfunction (spark plug(s), high-
tension cord(s), ignition coil assembly)
Fuel pressure out of specification
Fuel injector malfunction (clogged or leakage)
Engine compression out of specification
Valve lash (clearance) out of specification
Manifold absolute pressure sensor malfunction
Engine coolant temp. sensor malfunction
PCV valve malfunction
EVAP control system malfunction
DTC CONFIRMATION PROCEDURE
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester.
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Check vehicle and environmental condition for:
–Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Ambient temp.: –10C, 14F or higher
–Intake air temp.: 70C, 158F or lower
–Engine coolant temp.: –10 – 11 0C, 14 – 230F
4) Start engine and keep it at idle for 2 min. or more.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.
6) If DTC is not detected at idle, consult usual driving based on information obtained in “Customer complaint analy-
sis” and “Freeze frame data check”.
6-70 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE
DIAG. FLOW
TABLE“.
2Is there DTC other than Fuel system (DTC P0171 / P0172)
and misfire (DTC P0300-P0303)?Go to applicable
DTC Diag.
Flow Table.Go to Step 3.
3Check Ignition System.
1) Remove spark plugs and check them for;
Air gap: 1.0 – 1.1 mm (0.040 – 0.043 in.) See Fig. 1.
Carbon deposits
Insulator damage
Plug type
If abnormality is found, adjust, clean or replace.
2) Disconnect injector connector. See Fig. 2.
3) Connect spark plugs to high tension cords and then
ground spark plugs.
4) Crank engine and check that each spark plug sparks.
Are above check results satisfactory?Go to Step 4.Check ignition
system parts
(Refer to Section
6F).
4Check Fuel Pressure (Refer to Section 6E1 for details).
1) Release fuel pressure from fuel feed line.
2) Install fuel pressure gauge. See Fig. 3.
3) Check fuel pressure.
With fuel pump operating
and engine at stop : 160 – 210 kPa, 1.6 – 2.1 kg / cm
2,
22.7 – 29.9 psi.
At specified idle speed : 90 – 140 kPa, 0.9 – 1.4 kg / cm
2,
12.8 – 20.0 psi.
Is measured value as specified?
Go to Step 5.Go to Diag. Flow
Table B-3 fuel
pressure check.
5Check Fuel Injector and Circuit.
1) Turn ignition switch OFF and disconnect fuel injector
connector.
2) Check for proper connection to fuel injector at each terminal.
3) If OK, then check injector resistance. See Fig. 4.
Injector resistance: 0.5 – 1.5 Ω at 20C (68F).
4) Connect injector connector.
5) Check that fuel is injected out in conical shape from fuel
injector when running engine.
6) Check injector for fuel leakage after engine stop.
Fuel leakage: Less than 1 drop / min.
Is check result satisfactory?Go to Step 6.Check injector
circuit or replace
fuel injector.