6-28 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
ConditionPossible CauseReferring Item
Excessive
hydrocarbon (HC)
emission or carbon
monoxide (CO)Ignition system out of order
Faulty spark plug
Leaky or disconnected high-tension cord
Faulty ignition coil with ignitor
Low compression
Engine and emission control system out of
order
Lead contamination of three way catalytic
converter
Faulty evaporative emission control system
Fuel pressure out of specification
Closed loop system (A / F feed back
compensation) fails
–Faulty TP sensor
–Poor performance of ECT sensor or MAP
sensor
Faulty injector
Faulty fuel injector resistor
Faulty ECM (PCM)
Others
Engine not at normal operating temperature
Clogged air cleaner
Vacuum leaks
Spark plugs in Section 6F
High-tension cords in Section 6F
Ignition coil assembly in Section
6F
Refer to “Low compression”
section
Check for absence of filler neck
restrictor
EVAP control system in Section
6E1
Diagnostic Flow Table B-3
TP sensor in Section 6E1
ECT sensor or MAP sensor in
Section 6E1
Diagnostic Flow Table B-1
Fuel injector resistor in Section 6E1
Excessive nitrogen
oxides (NOx)
emissionIgnition system out of order
Improper ignition timing
Engine and emission control system out of
order
Lead contamination of catalytic converter
Fuel pressure out of specification
Closed loop system (A / F feed back
compensation) fails
–Faulty TP sensor
–Poor performance of ECT sensor or MAP
sensor
Faulty injector
Faulty fuel injector resistor
Faulty ECM (PCM)
See section 6F1
Check for absence of filler neck
restrictor.
Diagnostic Flow Table B-3
TP sensor in Section 6E1
ECT sensor or MAP sensor in
Section 6E1
Diagnostic Flow Table B-1
Fuel injector resistor in Section 6E1
ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-29
Ambient temp.
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 condition,
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 (PCM) and
output from ECM (PCM) as commands and there may be cases where the engine or actuator is not operating (in
the condition) 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.
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 DATAVEHICLE CONDITIONNORMAL CONDITION /
REFERENCE VALUES
FUEL SYSTEM B1 (FUEL
SYSTEM STATUS)At specified idle speed after warming upCLOSED (closed loop)
CALC LOAD
(CALCULATED LOADAt specified idle speed with no load after
warming up3 – 5%(
VALUE)At 2500 r / min with no load after warming up10 – 18%
COOLANT TEMP.
(ENGINE COOLANT
TEMP.)
At specified idle speed after warming up85 – 95C, 185 – 203F
SHORT FT BI (SHORT
TERM FUEL TRIM)At specified idle speed after warming up–20 – +20%
LONG FT BI (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 after
warming up29 – 48 kPa,
220 – 360 mmHg
ENGINE SPEEDAt idling with no load after warming upDesired idle speed
± 50 r / min
VEHICLE SPEEDAt stop0 km / h, 0 MPH
IGNITION ADVANCE
(IGNITION TIMING
ADVANCE FOR NO.1
CYLINDER)
At specified idle speed with no load after
warming up–1 – 18 BTDC
INTAKE AIR TEMP.At specified idle speed after warming up+35C (+63F)
–5C (–9F)
MAF (MASS AIR FLOW
RATE)
At specified idle speed with no load after
warming up1.0 – 3.0 gm / sec
RATE)At 2500 r / min with no load after warming up3.0 – 6.0 gm / sec
THROTTLE POS
(ABSOLUTEIgnition switch ON /Throttle valve fully closed7 – 18%
(ABSOLUTE
THROTTLE POSITION)
g
engine stoppedThrottle valve fully open70 – 90%
O2S B1 S1 (HEATED
OXYGEN SENSOR-1)At specified idle speed after warming up0.05 – 0.95 V
O2S B1 S2 (HEATED
OXYGEN SENSOR-2)When engine is running at 2000 r / min. for
3 min. or longer after warming up.0 – 0.95 V
O2S FT B1 S1At specified idle speed after warning up–20 – +20%
DIS. WITH MIL ON————
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.
6-36 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
CONNECTOR “C01”
TER-
MINALWIRE
COLORCIRCUITSTANDARD
VOLTAGECONDITION
1LgPower source for sensor4.75 – 5.25 VIgnition switch ON
2OrCamshaft position sensor (+)——
3W/BCrankshaft position sensor
(+)——
4Gr / GClosed throttle position switch
0 – 1 V
Ignition switch ON, ISC actuator
plunger is in contact with throttle lever
screw
4Gr / G(In ISC actuator)
4 – 6 V
Ignition switch ON
Plunger is apart from throttle lever
screw
5Lg / RManifold absolute pressure
sensor3.3 – 4.0 V
Ignition switch ON
Barometric pressure: 100 kPa,
760 mmHg
6Lg / WThrottle position sensor
0.2 – 1.0 V
Ignition switch ON, when clearance
between throttle lever and throttle stop
screw is less than 0.35 mm (0.014 in.)
2.8 – 4.8 VIgnition switch ON
Throttle valve at full open position
7Gr / WEngine coolant temp. sensor0.55 – 0.95 VIgnition switch ON
Engine coolant temp.: 80C (176F)
8P/BHeater of H02S-110 – 14 VIgnition switch ON
9GGround for sensors——
10WCamshaft position sensor (–)——
11W/RCrankshaft position sensor
(+)——
12W/BEFE heater monitor0 – 1 VHeater relay OFF12W/BEFE heater monitor10 – 14 VHeater relay ON
13RHeated oxygen sensor-1Refer to DTC flow chart
14GrIntake air temp. sensor2.0 – 2.7 V
Ignition switch ON
Sensor ambient temp.
(Intake air temp): 20C (68F)
10 – 14 VIgnition switch ON
15Bl / WPower steering pressure
switch (If equipped)
0 – 1 V
With engine running at idle speed,
turning steering wheel to the right or left
as far as it stops, repeating it a few
times
16B/YEngine start switch6 – 12 VWhile engine cranking16B/Yg
(Engine start signal)0 – 1 VOther than above
MAP sensorTo TP sensor
To other sensors
6-44 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
DTC P0105 MANIFOLD ABSOLUTE PRESSURE (MAP) CIRCUIT
MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
MAP: 5 kPa, 37.5 mmHg or less
(Low pressure – High vacuums – Low voltage)
or
MAP: 130 kPa, 975 mmHg or more
(High pressure – Low vacuums – High voltage)“G” circuit open
“Lg” circuit open or shorted to ground
“Lg / R” circuit open or shorted to ground
MAP sensor malfunction
ECM (PCM) malfunction
NOTE:
When DTC P0105, and / or P0120, P0510 are indicated together, it is possible that “Lg” circuit is open.
When DTC P0105, P0110, P0115 and / or P0120 are indicated together, it is possible that “G” 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.
ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-45
Fig. 1 for Step 2 Fig. 2 for Step 3
Scan tool
DLC
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 130 kPa or more or 5 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 “Lg / R” and “G” wire
terminals.
3) If OK, then with ignition switch ON, check
voltage at each of “Lg” and “Lg / R” wire
terminals. See Fig. 2.
Is voltage about 4 – 6 V at each terminal?Go to Step 4.“Lg” wire open or
shorted to ground circuit or
shorted to power circuit,
“Lg / R” wire open or
shorted to ground, poor
C01-5 connection or
C01-1 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
“Lg” wire, it is possible
that MAP sensor is also
faulty.
4Check MAP sensor according to “MAP
Sensor Individual Check” in Section 6E1.
Is it in good condition?“Lg” wire shorted to
“Lg / R” wire, “G” wire
open, poor C01-9
connection.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.Replace MAP sensor.