Page 615 of 1807
DI-200
- DIAGNOSTICSENGINE (2JZ-GTE)
428 Author: Date:
1997 SUPRA (RM502U)
3 Check the output voltage of heated oxygen sensor (bank 1 sensor 2).
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC 3.
(b) Warm up engine to normal operating temperature.
CHECK:
Read the output voltage of heated oxygen sensor (bank 1 sensor 2) when engine is suddenly raced.
HINT:
Perform quick racing to 4,000 rpm for 3 min. using accelerator pedal.
OK:
Heated oxygen sensor output voltage: Alternates from 0.4 V or less to 0.5 V or more.
OK Check that each connector is properly con-
nected.
NG
Replace heated oxygen sensor
(bank 1 sensor 2).
Page 616 of 1807
- 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
Page 617 of 1807
DI-202
- DIAGNOSTICSENGINE (2JZ-GTE)
430 Author: Date:
1997 SUPRA (RM502U)
2 Check for heated oxygen sensor data.
PREPARATION:
(a) Connect the OBDII scan tool or TOYOTA hand-held tester to the DLC3.
(b) Warm up engine to normal operating temperature.
CHECK:
Read the heated oxygen sensor output voltage and short-term fuel trim.
HINT:
Read the values for the same bank.
RESULT:
PatternHeated oxygen sensor output voltageShort-term fuel trim
1Lean condition (Changes at 0.55 V or less)Changes at about + 20 %
2Rich condition (Changes at 0.4 V or more)Changes at about - 20 %
3Except 1 and 2
3 Check for heated oxygen sensor
(See page DI-193).
1,2
3 Check fuel pressure (See page SF-5).
NG Check and repair fuel pump, pressure regulator,
fuel pipe line and filter (See page SF-1).
OK
4 Check injector injection (See page SF-25).
NG Replace injector.
OK
Page 618 of 1807
- 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).
Page 621 of 1807
P11799 IG0317 IG0151
A03065
1.1 mm
DI-206
- DIAGNOSTICSENGINE (2JZ-GTE)
434 Author: Date:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
1 Check spark plug and spark of misfiring cylinder.
PREPARATION:
(a) Remove the ignition coil (See page IG-6).
(b) Remove the spark plug.
CHECK:
(a) Check the carbon deposits on electrode.
(b) Check electrode gap.
OK:
(1) No large carbon deposit present.
Not wet with gasoline or oil.
(2) Electrode gap: 1.1 - 1.3 mm
(0.043 - 0.051 in.)
PREPARATION:
(a) Install the spark plug to the ignition coil, and connect the
ignition coil connector.
(b) Ground the spark plug.
(c) Disconnect injector connector.
CHECK:
Check if spark occurs while the engine is being cranked.
NOTICE:
To prevent excess fuel being injected from the injectors
during this test, don't crank the engine for more than 5 - 10
sec. at a time.
OK:
Spark jumps across electrode gap.
NG Replace or check ignition system (See page
IG-1).
OK
Page 622 of 1807
A00700
ON
Check Harness A
ECM
B20, 19, 18, 17, 16, 15
#10
(+)#20
(+)#30
(+)#40
(+)#50
(+)#60
(+)
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-207
435 Author: Date:
1997 SUPRA (RM502U)
2 Check voltage of ECM terminal for injector of failed cylinder.
PREPARATION:
(a) Connect Check Harness A (See page DI-164.).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between applicable terminal of ECM and body
ground.
OK:
Voltage: 9 - 14 V
OK Go to step 4.
NG
3 Check resistance of injector of misfiring cylinder (See page SF-25).
NG Replace injector.
OK
Check for open and short in harness and con-
nector between injector and ECM (See page
IN-28).
4 Check fuel pressure (See page SF-5).
NG Check and repair fuel pump, pressure regulator,
fuel pipe line and filter (See page SF-1).
OK
5 Check injector injection (See page SF-25).
Page 623 of 1807
DI-208
- DIAGNOSTICSENGINE (2JZ-GTE)
436 Author: Date:
1997 SUPRA (RM502U)
NG Replace injector.
OK
6 Check EGR system (See page EC-7).
NG Repair EGR system.
OK
7 Check mass air flow meter and engine coolant temp. sensor (See page SF-38,
SF-73).
NG Repair or replace.
OK
Check the compression pressure (See page EM-3), valve clearance (See page EM-4) and valve
timing (See page EM-15).
Page 625 of 1807
A00701
OFF
B50, 49
KNK1KNK2Check Harness A
DI-210
- DIAGNOSTICSENGINE (2JZ-GTE)
438 Author: Date:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
HINT:
DTC P0325 is for the knock sensor circuit on the front side.
DTC P0330 is for the knock sensor circuit on the rear side.
1 Check continuity between terminal KNK1, KNK2 of ECM connector and body,
ground.
PREPARATION:
Connect Check Harness A to the connectors on the wire har-
ness side (See page DI-164).
HINT:
The other side of Check Harness A is not connected to the ECM
terminals.
CHECK:
Measure resistance between terminal KNK1, KNK2 of ECM
connector and body ground.
HINT:
Connect terminal KNK1 to knock sensor 1.
Connect terminal KNK2 to knock sensor 2.
OK:
Resistance: 1 MW or higher
OK Go to step 3.
NG
2 Check knock sensor (See page SF-75).
NG Replace knock sensor.
OK
3 Check for open and short in harness and connector between ECM and knock
sensor (See page IN-28).
NG Repair or replace harness or connector.
OK
