ESP TOYOTA SUPRA 1986 Service Repair Manual

DTC 35 Barometric Pressure Sensor Circuit
CIRCUIT DESCRIPTION
The BARO sensor is built into the ECM. This is a semiconductor pressure sensor with properties which cause
its electrical resistance to change when stress is applied to the sensor's crystal (silicon) (piezoelectric effect).
This sensor is used to detect the atmospheric (absolute) pressure and outputs corresponding electrical signals.
Fluctuations in the air pressure cause changes in the intake air density, which can cause deviations in the air±
fuel ratio. The signals from BARO sensor are used to make corrections for these fluctuations. If the ECM detects
diagnostic trouble code º35º, the fail safe function operates and the atmospheric pressure is set at a constant
101.3 kPa (760 mmHg, 29.92 in.Hg).
 DTC No. Diagnostic Trouble Code Detecting Condition Trouble Area 
35
 
Open or short in BARO sensor circuit for 0.5
 

ECM 35  Oen or short in BARO sensor circuit for 0.5
sec. or more 
ECM
INSPECTION PROCEDURE
Are there any other codes (besides Code 35) being output?
Go to relevant diagnostic trouble code chart.
Replace engine control module.
± ENGINE2JZ±GE ENGINE TROUBLESHOOTINGEG±441

VSV Circuit for ACIS
CIRCUIT DESCRIPTION
The circuit opens and closes the IACV (Intake Air Control Valve) in response to the engine load in order
to increase the intake efficiency (ACIS: Acoustic Control Induction System).
When the engine speed is 4,500 rpm or less and throttle valve opening angle is 30° or more, or engine
speed is 4,500 rpm or more and throttle valve opening angle is 30° or less, the engine control module
turns the VSV ON and closes the IACV. At all other times, the VSV is OFF, so the IACV is open.
VSVIACV
ON
OFF
closed
open
EG±478± ENGINE2JZ±GE ENGINE TROUBLESHOOTING

PRECAUTION
1. Before working on the fuel system, disconnect the
negative (±) terminal cable from the battery.
HINT: Any diagnostic trouble code retained by the computer
will be erased when the negative (±) terminal cable is discon-
nected.
Therefore, if necessary, read the diagnosis before discon-
necting the negative (±) terminal cable from the battery.
2. Do not smoke or work near an open flame when working
on the fuel system.
3. Keep gasoline away from rubber or leather parts.
MAINTENANCE PRECAUTIONS
1. PRECAUTION WHEN CONNECTING GAUGE
(a) Use ba tte ry as th e po we r so u rce fo r th e timin g lig h t,
tachometer, etc.
(b) Connect the tester probe of a tachometer to the terminal IG

of the DLC1.
2. IN EVENT OF ENGINE MISFIRE, FOLLOWING
PRECAUTIONS SHOULD BE TAKEN
(a) Check proper connection of battery terminals, etc.
(b) After repair work, check that the ignition coil terminals and all
other ignition system lines are reconnected securely.
(c) When cleaning the engine compartment, be especially
careful to protect the electrical system from water.
3. PRECAUTIONS WHEN HANDLING OXYGEN SENSOR
(a) Do not allow oxygen sensor to drop or hit against an object.
(b) Do not allow the sensor to come into contact with water. EG±260
± ENGINESFI SYSTEM (2JZ±GTE)

IF VEHICLE IS EQUIPPED WITH MOBILE
RADIO SYSTEM (HAM, CB, ETC.)
If the vehicle is equipped with a mobile communication sys-
tem, refer to the precaution in the IN section.
AIR INDUCTION SYSTEM
1. Separation of the engine oil dipstick, oil filler cap, PCV hose,
etc. may cause the engine to run out of tune.
2. Disconnection, looseness or cracks in the parts of the air
induction system between the throttle body and cylinder
head will cause air suction and cause the engine to run out
of tune.
ELECTRONIC CONTROL SYSTEM
1. Before removing SFI wiring connectors, terminals, etc., first
disconnect the power by either turning the ignition switch
OFF or disconnecting the negative (±) terminal cable from the
battery.
HINT: Always check the diagnostic trouble code before dis-
connecting the negative (±) terminal cable from the battery.
2. When installing the battery, be especially careful not to
incorrectly connect the positive (+) and negative (±) cables.
3. Do not permit parts to receive a severe impact during removal
or installation. Handle all SFI parts carefully, especially the
ECM.
4. Do not be careless during troubleshooting as there are
numerous transistor circuits and even slight terminal contact
can cause further troubles.
5. Do not open the ECM cover.
6. When inspecting during rainy weather, take care to prevent
entry of water. Also, when washing the engine compartment,
prevent water from getting on the SFI parts and wiring
connectors.
7. Parts should be replaced as an assembly.
8. Care is required when pulling out and inserting wiring
connectors.
(a) Release the lock and pull out the connector, pulling on the
connectors.
(b) Fully insert the connector and check that it is locked.
± ENGINESFI SYSTEM (2JZ±GTE)EG±261

PRECAUTION
1. Before working on the fuel system, disconnect the
negative (±) terminal cable from the battery.
HINT: Any diagnostic trouble code retained by the computer
will be erased when the negative (±) terminal cable is discon-
nected.
Therefore, if necessary, read the diagnosis before discon-
necting the negative (±) terminal cable from the battery.
2. Do not smoke or work near an open flame when working
on the fuel system.
3. Keep gasoline away from rubber or leather parts.
MAINTENANCE PRECAUTIONS
1. PRECAUTION WHEN CONNECTING GAUGE
(a) Use ba tte ry as th e po we r so u rce fo r th e timin g lig h t,
tachometer, etc.
(b) Connect the tester probe of a tachometer to the terminal IG

of the DLC1.
2. IN EVENT OF ENGINE MISFIRE, FOLLOWING
PRECAUTIONS SHOULD BE TAKEN
(a) Check proper connection of battery terminals, etc.
(b) Handle high±tension cords carefully.
(c) After repair work, check that the ignition coil terminals and all
other ignition system lines are reconnected securely.
(d) When cleaning the engine compartment, be especially
careful to protect the electrical system from water.
3. PRECAUTIONS WHEN HANDLING OXYGEN SENSOR
(a) Do not allow oxygen sensor to drop or hit against an object.
(b) Do not allow the sensor to come into contact with water.
± ENGINESFI SYSTEM (2JZ±GE)EG±189

IF VEHICLE IS EQUIPPED WITH MOBIL
RADIO SYSTEM (HAM, CB, ETC.)
If the vehicle is equipped with a mobile communication sys-
tem, refer to the precaution in the IN section.
AIR INDUCTION SYSTEM
1. Separation of the engine oil dipstick, oil filler cap, PCV hose,
etc. may cause the engine to run out of tune.
2. Disconnection, looseness or cracks in the parts of the air
induction system between the throttle body and cylinder
head will cause air suction and cause the engine to run out
of tune.
ELECTRONIC CONTROL SYSTEM
1. Before removing SFI wiring connectors, terminals, etc., first
disconnect the power by either turning the ignition switch
OFF or disconnecting the negative (±) terminal cable from the
battery.
HINT: Always check the diagnostic trouble code before dis-
connecting the negative (±) terminal cable from the battery.
2. When installing the battery, be especially careful not to
incorrectly connect the positive (+) and negative (±) cables.
3. Do not permit parts to receive a severe impact during removal
or installation. Handle all SFI parts carefully, especially the
ECM.
4. Do not be careless during troubleshooting as there are
numerous transistor circuits and even slight terminal contact
can cause further troubles.
5. Do not open the ECM cover.
6. When inspecting during rainy weather, take care to prevent
entry of water. Also, when washing the engine compartment,
prevent water from getting on the SFI parts and wiring
connectors.
7. Parts should be replaced as an assembly.
8. Care is required when pulling out and inserting wiring
connectors.
(a) Release the lock and pull out the connector, pulling on the
connectors.
(b) Fully insert the connector and check that it is locked. EG±190
± ENGINESFI SYSTEMS (2JZ±GE)

* The system shown here is an EXAMPLE ONLY. It is different to the actual circuit shown in the SYSTEM CIRCUITS SECTION.
GROUND POINTS
9
The ground points circuit diagram shows the connections from all major parts to the respective ground points. When
troubleshooting a faulty ground point, checking the system circuits which use a common ground may help you identify the
problem ground quickly. The relationship between ground points ( , , and shown below) can also be
checked this way.

METER, ANALOG
Current flow activates a magnetic
coil which causes a needle to
move, thereby providing a relative
display against a background
calibration. LED (LIGHT EMITTING DIODE)
Upon current flow, these diodes
emit light without producing the
heat of a comparable light. IGNITION COIL
Converts low±voltage DC current
into high±voltage ignition current
for firing the spark plugs. 1. SINGLE
FILAMENT
GROUND
The point at which wiring attaches
to the Body, thereby providing a
return path for an electrical circuit;
without a ground, current cannot
flow.Current flow causes a headlight
filament to heat up and emit light.
A headlight may have either a
single (1) filament or a double (2)
filament. BATTERY
Stores chemical energy and
converts it into electrical energy.
Provides DC current for the auto's
various electrical circuits.
CAPACITOR (Condenser)
A small holding unit for temporary
storage of electrical voltage.
CIRCUIT BREAKER
Basically a reusable fuse, a circuit
breaker will heat and open if too
much current flows through it. Some
units automatically reset when cool,
others must be manually reset.
DIODE
A semiconductor which allows
current flow in only one direction.
DIODE, ZENER
A diode which allows current flow
in one direction but blocks reverse
flow only up to a specific voltage.
Above that potential, it passes the
excess voltage. This acts as a
simple voltage regulator.
FUSE
A thin metal strip which burns
through when too much current
flows through it, thereby stopping
current flow and protecting a
circuit from damage.
FUSIBLE LINK
A heavy±gauge wire placed in
high amperage circuits which
burns through on overloads,
thereby protecting the circuit.
The numbers indicate the cross±
section surface area of the wires.HORN
An electric device which sounds a
loud audible signal.
LIGHT
Current flow through a filament
causes the filament to heat up
and emit light.
METER, DIGITAL
Current flow activates one or
many LED's, LCD's, or fluorescent
displays, which provide a relative
or digital display.
MOTOR
A power unit which converts
electrical energy into mechanical
energy, especially rotary motion. CIGARETTE LIGHTER
An electric resistance heating
element.
DISTRIBUTOR, IIA
Channels high±voltage current
from the ignition coil to the
individual spark plugs.2. DOUBLE
FILAMENT HEADLIGHTS
FUEL
(for High Current Fuse or
Fusible Link.)
(for Medium Current Fuse)
M
16
GLOSSARY OF TERMS AND SYMBOLS

71
2. CONTROL SYSTEM
*SEQUENTIAL MULTIPORT FUEL INJECTION (ELECTRONIC FUEL INJECTION) SYSTEM
THE SEQUENTIAL MULTIPORT FUEL INJECTION (ELECTRONIC FUEL INJECTION) SYSTEM MONITORS THE ENGINE CONDITION
THROUGH THE SIGNALS INPUT FROM EACH SENSOR (INPUT SIGNALS FROM (1) TO (13) ETC.) TO THE ENGINE CONTROL
MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU). THE BEST FUEL INJECTION TIMING IS DECIDED
BASED ON THIS DATA AND THE PROGRAM MEMORIZED BY THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY
CONTROLLED TRANSMISSION ECU), AND THE CONTROL SIGNAL IS OUTPUT TO TERMINALS #10, #20, #30, 40, #50 AND #60 OF
THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) TO OPERATE THE
INJECTOR (INJECT THE FUEL). THE SEQUENTIAL MULTIPORT FUEL INJECTION (ELECTRONIC FUEL INJECTION) SYSTEM
PRODUCES CONTROLS OF FUEL INJECTION OPERATION BY THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY
CONTROLLED TRANSMISSION ECU) IN RESPONSE TO THE DRIVING CONDITIONS.
*ESA (ELECTRONIC SPARK ADVANCE) SYSTEM
THE ESA SYSTEM MONITORS THE ENGINE CONDITION THROUGH THE SIGNALS INPUT TO THE ENGINE CONTROL MODULE
(ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) FROM EACH SENSOR (INPUT SIGNALS FROM (1), (2), (4) TO
(13) ETC.). THE BEST IGNITION TIMING IS DECIDED ACCORDING TO THIS DATA AND THE MEMORIZED DATA IN THE ENGINE
CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) AND THE CONTROL SIGNAL IS OUTPUT
TO TERMINALS IGT1, IGT2, IGT3, IGT4, IGT5 AND IGT6 THESE SIGNALS CONTROL THE IGNITER TO PROVIDE THE BEST IGNITION
TIMING FOR THE DRIVING CONDITIONS.
*HEATED OXYGEN SENSOR HEATER CONTROL SYSTEM
THE MAIN HEATED OXYGEN SENSOR, SUB HEATED OXYGEN SENSOR HEATER CONTROL SYSTEM TURNS THE HEATER ON
WHEN THE INTAKE AIR VOLUME IS LOW (TEMP. OF EXHAUST EMISSIONS IS LOW), AND WARMS UP THE OXYGEN SENSOR TO
IMPROVE DETECTION PERFORMANCE OF THE SENSOR. THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY
CONTROLLED TRANSMISSION ECU) EVALUATES THE SIGNALS FROM EACH SENSOR (INPUT SIGNALS FROM (1), (2), (4), (9) TO
(11) ETC.), AND OUTPUTS CURRENT TO TERMINALS HT1, HT2 TO CONTROL THE HEATER.
*IDLE AIR CONTROL (IDLE SPEED CONTROL) SYSTEM
THE IDLE AIR CONTROL (ISC) SYSTEM (STEP MOTOR TYPE) INCREASES THE ENGINE SPEED AND PROVIDES IDLING STABILITY
FOR FAST IDLE±UP WHEN THE ENGINE IS COLD, AND WHEN THE IDLE SPEED HAS DROPPED DUE TO ELECTRICAL LOAD AND SO
ON. THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) EVALUATE THE
SIGNALS FROM EACH SENSOR (INPUT SIGNALS FROM (1), (4), (5), (8), (9), (11) ETC.), OUTPUTS CURRENT TO TERMINALS ISC1,
ISC2, ISC3 AND ISC4 TO CONTROL THE IDLE AIR CONTROL VALVE (ISC VALVE).
*EGR CONTROL SYSTEM
THE EGR CONTROL SYSTEM DETECTS THE SIGNAL FROM EACH SENSOR (INPUT SIGNALS FROM (1), (4), (9), (10) ETC.), AND
OUTPUTS CURRENT TO TERMINAL EGR TO CONTROL THE EGR VALVE.
*FUEL PUMP CONTROL SYSTEM
THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) OUTPUTS CURRENT TO
TERMINAL FPC AND CONTROLS THE FUEL PUMP ECU AND FUEL PUMP DRIVE SPEED IN RESPONSE TO THE DRIVING
CONDITIONS.
3. DIAGNOSIS SYSTEM
WITH THE DIAGNOSIS SYSTEM, WHEN THERE IS A MALFUNCTION IN THE ENGINE CONTROL MODULE (ENGINE AND
ELECTRONICALLY CONTROLLED TRANSMISSION ECU) SIGNAL SYSTEM, THE MALFUNCTIONING SYSTEM IS RECORDED IN THE
MEMORY. THE MALFUNCTIONING SYSTEM CAN BE FOUND BY READING THE CODE DISPLAYED BY THE MALFUNCTION INDICATOR
LAMP (CHECK ENGINE WARNING LIGHT).
4. FAIL±SAFE SYSTEM
WHEN A MALFUNCTION HAS OCCURRED IN ANY SYSTEM, IF THERE IS A POSSIBILITY OF ENGINE TROUBLE BEING CAUSED BY
CONTINUED CONTROL BASED ON THE SIGNALS FROM THAT SYSTEM, THE FAIL±SAFE SYSTEM EITHER CONTROLS THE SYSTEM
BY USING DATA (STANDARD VALUES) RECORDED IN THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY
CONTROLLED TRANSMISSION ECU) MEMORY OR ELSE STOPS THE ENGINE.

83
(13) ENGINE KNOCK SIGNAL CIRCUIT
ENGINE KNOCKING IS DETECTED BY KNOCK SENSOR FRONT AND REAR SIDE AND THE SIGNAL IS INPUT INTO TERMINALS
KNK1 AND KNK2 AS A CONTROL SIGNAL.
2. CONTROL SYSTEM
*SEQUENTIAL MULTIPORT FUEL INJECTION (ELECTRONIC FUEL INJECTION) SYSTEM
THE SEQUENTIAL MULTIPORT FUEL INJECTION (ELECTRONIC FUEL INJECTION) SYSTEM MONITORS THE ENGINE CONDITION
THROUGH THE SIGNALS INPUT FROM EACH SENSOR (INPUT SIGNALS FROM (1) TO (13) ETC.) TO THE ENGINE CONTROL
MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU). THE BEST FUEL INJECTION TIMING IS DECIDED
BASED ON THIS DATA AND THE PROGRAM MEMORIZED BY THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY
CONTROLLED TRANSMISSION ECU), AND THE CONTROL SIGNAL IS OUTPUT TO TERMINALS #10, #20, #30, 40, #50 AND #60 OF
THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) TO OPERATE THE
INJECTOR (INJECT THE FUEL). THE SEQUENTIAL MULTIPORT FUEL INJECTION (ELECTRONIC FUEL INJECTION) SYSTEM
PRODUCES CONTROLS OF FUEL INJECTION OPERATION BY THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY
CONTROLLED TRANSMISSION ECU) IN RESPONSE TO THE DRIVING CONDITIONS.
*ESA (ELECTRONIC SPARK ADVANCE) SYSTEM
THE ESA SYSTEM MONITORS THE ENGINE CONDITION THROUGH THE SIGNALS INPUT TO THE ENGINE CONTROL MODULE
(ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) FROM EACH SENSOR (INPUT SIGNALS FROM (1), (2), (4) TO
(13) ETC.). THE BEST IGNITION TIMING IS DECIDED ACCORDING TO THIS DATA AND THE MEMORIZED DATA IN THE ENGINE
CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) AND THE CONTROL SIGNAL IS OUTPUT
TO TERMINAL IGT. THIS SIGNAL CONTROLS THE IGNITER TO PROVIDE THE BEST IGNITION TIMING FOR THE DRIVING
CONDITIONS.
*HEATED OXYGEN SENSOR HEATER CONTROL SYSTEM (FOR CALIFORNIA)
THE MAIN HEATED OXYGEN SENSOR FRONT AND REAR SIDE, SUB HEATED OXYGEN SENSOR HEATER CONTROL SYSTEM
TURNS THE HEATER ON WHEN THE INTAKE AIR VOLUME IS LOW (TEMP. OF EXHAUST EMISSIONS IS LOW), AND WARMS UP THE
OXYGEN SENSOR TO IMPROVE DETECTION PERFORMANCE OF THE SENSOR. THE ENGINE CONTROL MODULE (ENGINE AND
ELECTRONICALLY CONTROLLED TRANSMISSION ECU) EVALUATES THE SIGNALS FROM EACH SENSOR (INPUT SIGNALS FROM
(1), (2), (4), (9) TO (11) ETC.), AND OUTPUTS CURRENT TO TERMINALS HT1, HT2, HT3 TO CONTROL THE HEATER.
*IDLE AIR CONTROL (IDLE SPEED CONTROL) SYSTEM
THE IDLE AIR CONTROL (ISC) SYSTEM (STEP MOTOR TYPE) INCREASES THE ENGINE SPEED AND PROVIDES IDLING STABILITY
FOR FAST IDLE±UP WHEN THE ENGINE IS COLD, AND WHEN THE IDLE SPEED HAS DROPPED DUE TO ELECTRICAL LOAD AND SO
ON. THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) EVALUATES THE
SIGNALS FROM EACH SENSOR (INPUT SIGNALS FROM (1), (4), (5), (8), (9), (11) ETC.), OUTPUTS CURRENT TO TERMINALS ISC1,
ISC2, ISC3 AND ISC4 TO CONTROL THE IDLE AIR CONTROL VALVE (ISC VALVE).
*EGR CONTROL SYSTEM
THE EGR CONTROL SYSTEM DETECTS THE SIGNAL FROM EACH SENSOR (INPUT SIGNALS FROM (1), (4), (9), (10) ETC.), AND
OUTPUTS CURRENT TO TERMINAL EGR TO CONTROL THE EGR VALVE.
*FUEL PUMP CONTROL SYSTEM
THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) OUTPUTS CURRENT TO
TERMINAL FPC AND CONTROLS THE FUEL PUMP ECU AND FUEL PUMP DRIVE SPEED IN RESPONSE TO THE DRIVING
CONDITIONS.
*ACIS (ACOUSTIC CONTROL INDUCTION SYSTEM)
ACIS INCLUDES A VALVE IN THE BULKHEAD SEPARATING THE SURGE TANK INTO TWO PARTS. THIS VALVE IS OPENED AND
CLOSED IN ACCORDANCE WITH THE DRIVING CONDITIONS TO CONTROL THE INTAKE MANIFOLD LENGTH IN TWO STAGES FOR
INCREASED ENGINE OUTPUT IN ALL RANGES FROM LOW TO HIGH SPEEDS.
THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) JUDGES THE VEHICLE
SPEED BY THE SIGNALS ((4), (5)) FROM EACH SENSOR AND OUTPUTS SIGNALS TO THE TERMINAL ACIS TO CONTROL THE VSV
(FOR INTAKE CONTROL VALVE).
3. DIAGNOSIS SYSTEM
WITH THE DIAGNOSIS SYSTEM, WHEN THERE IS A MALFUNCTION IN THE ENGINE CONTROL MODULE (ENGINE AND
ELECTRONICALLY CONTROLLED TRANSMISSION ECU) SIGNAL SYSTEM, THE MALFUNCTIONING SYSTEM IS RECORDED IN THE
MEMORY. THE MALFUNCTIONING SYSTEM CAN BE FOUND BY READING THE CODE DISPLAYED BY THE MALFUNCTION INDICATOR
LAMP (CHECK ENGINE WARNING LIGHT).
4. FAIL±SAFE SYSTEM
WHEN A MALFUNCTION HAS OCCURRED IN ANY SYSTEM, IF THERE IS A POSSIBILITY OF ENGINE TROUBLE BEING CAUSED BY
CONTINUED CONTROL BASED ON THE SIGNALS FROM THAT SYSTEM, THE FAIL±SAFE SYSTEM EITHER CONTROLS THE SYSTEM
BY USING DATA (STANDARD VALUES) RECORDED IN THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY
CONTROLLED TRANSMISSION ECU) MEMORY OR ELSE STOPS THE ENGINE.