1997 TOYOTA SUPRA engine coolant

A00697
Cover
Atmosphere
Housing
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
HeaterPlatinum Electrode
Coating (Ceramic)
Output Voltage
Exhaust GasIdeal Air-Fuel Mixture
Richer - Air Fuel Ratio - Leaner DI-190
- DIAGNOSTICSENGINE (2JZ-GTE)
418 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0125 Insufficient Coolant Temp. for Closed Loop
Fuel Control
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three-way cata-
lytic converter is used, but for the most efficient use of the three-way catalytic converter, the air-fuel ratio
must be precisely controlled so that it is always close to the stoichiometric air-fuel ratio.
The oxygen sensor has the characteristic whereby its output voltage changes suddenly in the vicinity of the
stoichiometric air-fuel ratio. This characteristic is used to detect the oxygen concentration in the exhaust
gas and provide feedback to the computer for control of the air-fuel ratio.
When the air-fuel ratio becomes LEAN, the oxygen concentration in the exhaust increases and the oxygen
sensor informs the ECM of the LEAN condition (small electromotive force: 0 V).
When the air-fuel ratio is RICHER than the stoichiometric air-fuel ratio the oxygen concentration in the ex-
haust gas is reduced and the oxygen sensor informs the ECM of the RICH condition (large electromotive
force: 1 V).
The ECM judges by the electromotive force from the oxygen sensor whether the air-fuel ratio is RICH or
LEAN and controls the injection time accordingly. However, if malfunction of the oxygen sensor causes out-
put of abnormal electromotive force, the ECM is unable to perform accurate air-fuel ratio control.
The heated oxygen sensors include a heater which heats the Zirconia element. The heater is controlled by
the ECM. When the intake air volume is low (the temperature of the exhaust gas is low) current flows to the
heater to heat the sensor for accurate oxygen concentration detection.
DTC No.DTC Detecting ConditionTrouble Area
P0125
After the engine is warmed up, heated oxygen sensor output
does not indicate RICH even once when conditions (a), (b) and
(c) continue for at least 2 min. :
(a) Engine speed: 1,500 rpm or more
(b) Vehicle speed: 40 - 100 km/h (25 - 62 mph)
(c) Closed throttle position SW: OFF

Open or short in heated oxygen sensor circuit

Heated oxygen sensor
HINT:
After confirming DTC P0125 use the OBD II scan tool or TOYOTA hand-held tester to confirm voltage output
of heated oxygen sensor from ºCURRENT DATAº.
If voltage output of heated oxygen sensor is 0 V, heated oxygen sensor circuit may be open or short.
DI4ST-01

FI7130
Vehicle speed
50 - 65 km/h
(31 - 40 mph)
Idling
IG SW OFF(5) (3)
(1) (2)
1 - 3 min.1 min.
Time
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-193
421 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0130 Heated Oxygen Sensor Circuit Malfunction
(Bank 1 Sensor 1)
CIRCUIT DESCRIPTION
Refer to ºInsufficient Coolant Temp. for Closed Loop Fuel Controlº on page DI-190.
DTC No.DTC Detecting ConditionTrouble Area
P0130
Voltage output of heated oxygen sensor remains at 0.4 V or
more, or 0.55 V or less, during idling after the engine is
warmed up (2trip detection logic)
Heated oxygen sensor

Fuel trim malfunction
HINT:

Bank 1 refers to the bank that includes cylinder No.1.

Sensor 1 refers to the sensor closer to the engine body.
The heated oxygen sensor output voltage and the short-term fuel trim value can be read using the OBD II
scan tool or TOYOTA hand-held tester.
WIRING DIAGRAM
Refer to page DI-190 for the WIRING DIAGRAM.
CONFIRMATION DRIVING PATTEN
(1) Connect the TOYOTA hand-held tester to the DLC3.
(2) Switch the TOYOTA hand-held tester from normal mode to check mode (See page DI-147).
(3) Start the engine and warm it up with all accessory switches OFF.
(4) Drive the vehicle at 50 - 65 km/h (31 - 40 mph) for 1 - 3 min. to warm up the heated oxygen sensor.
(5) Let the engine idle for 1 min.
HINT:
If a malfunction exists, the MIL will light up during step (5).
NOTICE:
If the conditions in this test are not strictly followed, detection of the malfunction will not be possible.
If you do not have a TOYOTA hand-held tester, turn the ignition switch OFF after performing steps
(3) to (5), then perform steps (3) to (5) again.
DI4SU-01

DI-196
- DIAGNOSTICSENGINE (2JZ-GTE)
424 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0133 Heated Oxygen Sensor Circuit Slow
Response (Bank 1 Sensor 1)
CIRCUIT DESCRIPTION
Refer to ºInsufficient Coolant Temp. for Closed Loop Fuel Controlº on page DI-190.
DTC No.DTC Detecting ConditionTrouble Area
P0133
Response time for the heated oxygen sensor voltage output to
change from rich to lean, or from lean to rich, is 1 sec. or more
during idling after the engine is warmed up
(2trip detection logic)

Heated oxygen sensor
HINT:

Bank 1 refers to the bank that includes cylinder No.1.

Sensor 1 refers to the sensor closer to the engine body.
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0133) being output?
YES Go to relevant DTC chart.
NO
Replace heated oxygen sensor.
DI4SV-01

BE6653S02437A03033
ON
Check Harness A
B72, 71
HT1(+) HTS(+)
ECM
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-197
425 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0135 Heated Oxygen Sensor Heater Circuit
Malfunction (Bank 1 Sensor 1)
DTC P0141 Heated Oxygen Sensor Heater Circuit
Malfunction (Bank 1 Sensor 2)
CIRCUIT DESCRIPTION
Refer to ºInsufficient Coolant Temp. for Closed Loop Fuel Controlº on page DI-190.
DTC No.DTC Detecting ConditionTrouble Area
P0135
When the heater operates, heater current exceeds 2 A
(2 trip detection logic)
Open or short in heater circuit of heated oxygen sensor
Htd htP0135
P0141Heater current of 0.25 A or less when the heater operates
(2 trip detection logic)
Heated oxygen sensor heater

ECM
HINT:

Bank 1 refers to the bank that includes cylinder No.1.

Sensor 1 refers to the sensor closer to the engine body.

Sensor 2 refers to the sensor farther away from the engine body.
WIRING DIAGRAM
Refer to page DI-190 for the WIRING DIAGRAM.
INSPECTION PROCEDURE
1 Check voltage between terminals HT1, HTS of ECM connector and body ground.
PREPARATION:
(a) Connect Check Harness A (See page DI-164).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals HT1, HTS of ECM connec-
tor and body ground.
HINT:

Connect terminal HT1 to bank 1 sensor 1.

Connect terminal HTS to bank 1 sensor 2.
OK:
Voltage: 9 - 14 V
OK Check and replace ECM (See page IN-28).
NG
DI4SW-01

- DIAGNOSTICSENGINE (2JZ-GTE)
DI-199
427 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0136 Heated Oxygen Sensor Circuit Malfunction
(Bank 1 Sensor 2)
CIRCUIT DESCRIPTION
Refer to ºInsufficient Coolant Temp. for Closed Loop Fuel Controlº on page DI-190.
DTC No.DTC Detecting ConditionTrouble Area
P0136
Voltage output of the heated oxygen sensor (bank 1 sensor 2)
remains at 0.4 V or more or 0.5 V or less when the vehicle is
driven at 40 km/h (25 mph) or more after the engine is warmed
up
(2 trip detection logic)

Heated oxygen sensor
HINT:

Bank 1 refers to the bank that includes cylinder No.1.

Sensor 2 refers to the sensor farther away from the engine body.
WIRING DIAGRAM
Refer to page DI-190 for the WIRING DIAGRAM.
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0136) being output?
YES Go to relevant DTC chart.
NO
2 Check for open and short in harness and connector between ECM and heated
oxygen sensor (See page IN-28).
NG Repair or replace harness or connector.
OK
DI4SX-01

- DIAGNOSTICSENGINE (2JZ-GTE)
DI-201
429 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0171 System too Lean (Fuel Trim)
DTC P0172 System too Rich (Fuel Trim)
CIRCUIT DESCRIPTION
ºFuel trimº refers to the feedback compensation value compared against the basic injection time. Fuel trim
includes short-term fuel trim and long-term fuel trim.
ºShort-term fuel trimº is the short-term fuel compensation used to maintain the air-fuel ratio at its ideal
theoretical value. The signal from the heated oxygen sensor indicates whether the air-fuel ratio is RICH or
LEAN compared to the ideal theoretical value, triggering a reduction in fuel volume if the air-fuel ratio is rich,
and an increase in fuel volume if it is lean.
ºLong-term fuel trimº is overall fuel compensation carried out long-term to compensate for continual devi-
ation of the short-term fuel trim from the central value due to individual engine differences, wear over time
and changes in the usage environment.
If both the short-term fuel trim and long-term fuel trim are LEAN or RICH beyond a certain value, it is de-
tected as a malfunction and the MIL lights up.
DTC No.DTC Detecting ConditionTrouble Area
P0171
When the air fuel ratio feedback is stable after engine warning
up, the fuel trim is considerably in error on the RICH side
(2 trip detection logic)

Air intake (hose loose)

Fuel line pressure

Injector blockage

Heated oxygen sensor malfunction

Mass air flow meter

Engine coolant temp. sensor
P0172
When the air fuel ratio feedback is stable after engine warning
up, the fuel trim is considerably in error on the LEAN side
(2 trip detection logic)

Fuel line pressure

Injector blockage, leak

Heated oxygen sensor malfunction

Mass air flow meter

Engine coolant temp. sensor
HINT:

When DTC P0171 is recorded, the actual air-fuel ratio is on the LEAN side. When DTC P0172 is re-
corded, the actual air-fuel ratio is on the RICH side.

If the vehicle runs out of fuel, the air-fuel ratio is LEAN and DTC P0171 is recorded. The MIL then
comes on.

If the total of the short-term fuel trim value and long-term fuel trim value is within ± 35 %, the system
is functioning normally.
INSPECTION PROCEDURE
1 Check air induction system (See page SF-1).
NG Repair or replace.
OK
DI4SY-01

- DIAGNOSTICSENGINE (2JZ-GTE)
DI-203
431 Author
: Date
:
1997 SUPRA (RM502U)
5 Check mass air flow meter and engine coolant temp. sensor
(See page DI-170, DI-179).
NG Repair or replace.
OK
6 Check for spark and ignition (See page IG-1).
NG Repair or replace.
OK
Check and replace ECU (See page IN-28).

DI-204
- DIAGNOSTICSENGINE (2JZ-GTE)
432 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0300 Random/Multiple Cylinder Misfire Detected
DTC P0301 Cylinder 1 Misfire Detected
DTC P0302 Cylinder 2 Misfire Detected
DTC P0303 Cylinder 3 Misfire Detected
DTC P0304 Cylinder 4 Misfire Detected
DTC P0305 Cylinder 5 Misfire Detected
DTC P0306 Cylinder 6 Misfire Detected
CIRCUIT DESCRIPTION
Misfire: The ECM uses the crankshaft position sensor and camshaft position sensor to monitor changes in
the crankshaft rotation for each cylinder.
The ECM counts the number of times the engine speed change rate indicates that misfire has occurred.
When the misfire rate equals or exceeds the count indicating that the engine condition has deteriorated, the
MIL lights up.
If the misfire rate is high enough and the driving conditions will cause catalyst overheating, the MIL blinks
when misfiring occurs.
DTC No.DTC Detecting ConditionTrouble Area
P0300Misfiring of random cylinders is detected during the any
particular 200 or 1,000 revolutions
Ignition system

Injector
P0301
P0302
P0303For any particular 200 revolutions of the engine, misfiring is
detected which can cause catalyst overheating (This causes
MIL to blink)
j

Fuel line pressure

EGR

Compression pressure


Valve clearance not to specificationP0303
P0304
P0305
P0306For any particular 1,000 revolutions of the engine, misfiring
is detected which causes a deterioration in emission (2 trip
detection logic)

Valve clearance not to specification

Valve timing

Mass air flow meter

Engine coolant temp. sensor
HINT:
When the 2 or more codes for a misfiring cylinder are recorded repeatedly but no Random Misfire code is
recorded, it indicates that the misfires were detected and recorded at different times.
DI4SZ-01