Page 2025 of 2543

DTC 13 G NE Signal Circuit (No.2)
CIRCUIT DESCRIPTION
Refer to G, NE signal circuit (No.1) on page EG±515
DTC No. Diagnostic Trouble Code Detecting Condition Trouble Area
No NE signal to ECM for 0.1 sec. or more at
1,000 rpm or more
Open or short in crankshaft position
sensor circuit
Crankshaft position sensor
ECM
13
NE signal does not pulse 12 times to ECM
during the interval between G1 and G2 pulses
Open or short in crankshaft position
sensor circuit
Mechanical system malfunction (skipping
teeth of timing belt, belt stretched)
Crankshaft position sensor
ECM
Deviation in G (G1, G2) and NE signal
Continues for 3 sec. during idling
throttle fully closed after engine warmed up
Mechanical system malfunction (skipping
teeth of timing belt, belt stretched)
Camshaft position sensor No. 1, No.2
ECM
INSPECTION PROCEDURE
Inspect sensor installation. Check if any teeth of NE signal plate are broken.
Tighten sensor.
Replace timing rotor.
Adjust valve timing (repair or replace timing belt).
Check valve timing (Check for loose and jumping teeth of timing belt
(See page EG±33)).
Check for intermittent problems.
(See page EG±505)
EG±518± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING
Page 2026 of 2543

DTC 14 Ignition Signal Circuit
CIRCUIT DESCRIPTION
The ECM determines the ignition timing, turns on Tr1 at a predetermined angle (°CA) before the desired ignition
timing and outputs an ignition signal (IGT) º1º to the igniter.
Since the width of the IGT signal is constant, the dwell angle control circuit in the igniter determines the time
the control circuit starts primary current flow to the ignition coil based on the engine rpm and ignition timing one
revolution ago, that is, the time the Tr
2 turns on.
When it reaches the ignition timing, the ECM turns Tr
1 off and outputs the IGT signal ºOº.
This turns Tr
2 off, interrupting the primary current flow and generating a high voltage in the secondary coil which
causes the spark plug to spark. Also, by the counter electromotive force generated when the primary current
is interrupted, the igniter sends an ignition confirmation signal (IGF) to the ECM.
The ECM stops fuel injection as a fail safe function when the IGF signal is not input to the ECM.
DTC No. Diagnostic Trouble Code Detecting Condition Trouble Area
14
No IGF signal to ECM for 4 ~ 7 consecutive
IGT signals with engine speed less than
3,000 rpm
Open or short in IGF circuit from igniter to
ECM
Igniter
ECM
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±519
Page 2027 of 2543

Check for spark.
(1) Remove ignition coil. (See page IG±26)
(2) Remove spark plug.
(3) Install the spark plug to the ignition coil, and connect
the ignition coil connector.
(4) Ground the spark plug.
Check if spark occurs while engine is being cranked.
To prevent excess fuel being injected from injectors dur-
ing this test, don't crank the engine for more than 1Ð2
seconds at a time.
Check for open and short in harness and connector in IGF signal circuit
between engine control module and igniter (See page IN±30).
Repair or replace harness or connector.
Replace igniter.
Check and replace engine control module.
Disconnect igniter connector and check voltage between terminal IGF of
engine control module connector and body ground.
(1) Disconnect igniter connector.
(2) Connect SST (check harness ªAº).
(See page EG±510)
SST 09990±01000
(3) Turn ignition switch ON.
Measure voltage between terminal IGF of engine con-
trol module connector and body ground.
Voltage: 4.5 Ð 5.5 V
INSPECTION PROCEDURE
EG±520± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING
Page 2028 of 2543
(See page EG±510)
During idling, check waveforms between termi±
nals IGT1, IGF and E1 of engine control module.
HINT: The correct rectangular waveforms are as
shown, IGT2, IGT3, IGT4, IGT5 and IGT6
signal waveforms are same as IGT1 signal
waveform.
Check voltage between terminal IGT (1 ~ 6) of engine control module
connector and body ground.
Connect SST (check harness ªAº).
(See page EG±510)
SST 09990±01000
Measure voltage between terminal IGT (1 ~ 6) of engine
control module connector and body ground when en-
gine is cranked.
Voltage: 0.5 Ð 1.0 V
(Neither 0 V nor 5 V)
Check voltage between terminal 2 of igniter connector (I2) and body ground.
Disconnect igniter connector.
Measure voltage between terminal 2 of igniter connec-
tor (I2) and body ground, when ignition switch is turned
to ªONº and and ªSTARTº position.
Voltage: 9 Ð 14 V
Check and repair igniter power source circuit.
ReferenceINSPECTION USING OSCILLOSCOPE
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±521
Page 2029 of 2543
Check for open and short in harness and connector between ignition
switch and ignition coil, ignition coil and igniter (See page IN±30).
Disconnect ignition coil connector.
(See page IG±23)
Measure resistance between terminals of ignition coil
connector.
Repair or replace harness or connector.
Check ignition coil.
ªColdº is from Ð 10°C (14°F) to 50°C (122°F) and ªHotº is
from 50°C (122°F) to 100°C (212°F).
Replace ignition coil.
Replace igniter.
EG±522± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING
Page 2030 of 2543
Disconnect igniter connector and check voltage between terminal
IGT (1 ~ 6) of engine control module connector and body ground.
Disconnect igniter connector.
Measure voltage between terminal IGT (1 ~ 6) of engine
control module connector and body ground when engine
is cranked.
Voltage: 0.5 Ð 1.0 V
(Neither 0 V nor 5 V)
Replace igniter.
Check for open and short in harness and connector in IGT (1 ~ 6) signal
circuit between engine control module and igniter (See page IN±30).
During idling, check waveforms between terminals
IGF1, IGF and E1 of engine control module.
HINT: The correct rectangular waveforms are as shown,
IGT2, IGT3, IGT4, IGT5 and IGT6 signal wave±
forms are same as IGT1 signal waveform.
Repair or replace harness or connector.
Check and replace engine control module.
ReferenceINSPECTION USING OSCILLOSCOPE
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±523
Page 2031 of 2543
DTC 16 A T Control Signal Malfunction
CIRCUIT DESCRIPTION
The signal from the A/T CPU retards the ignition timing of the engine during A/T gear shifting, thus momentarily
reducing torque output of the engine for smooth clutch operation inside the transmission and reduced shift
shock.
DTC No.
Diagnostic Trouble Code Detecting Condition
Trouble Area
16
Fault in communications between the engine
CPU and A/T CPU in the ECM
ECM
If the ECM detects the diagnostic trouble code º16º in memory, it prohibits the torque control of the A/T which
performs smooth gear shifting.
INSPECTION PROCEDURE
Are there any other codes (besides Code 16) being output?
Go to relevant diagnostic trouble code chart.
Replace engine control module.
EG±524± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING
Page 2032 of 2543

See page EG±503.
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three±way
catalytic converter is used, but for 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
exhaust gas is reduced and the oxygen sensor informs the ECM of the RICH condition (large electro-
motive force: 1 V).
The ECm judges by the electromotive force from the oxygen sensor whether the air±fuel ratio if RICH
or LEAN and controls the injection duration accordingly. However, if malfunction of the oxygen sensor
causes an output of abnormal electromotive force, the ECM is unable to perform accurate air±fuel ratio
control.
The main heated oxygen sensor include a heater which heats the Zirconia element. The heater is con-
trolled by the ECM. When the intake air volume is low (the temperature of the exhaust has is low) current
flows to the heater to heat the sensor for accurate oxygen concentration detection.)
Diagnostic Trouble Code Detecting ConditionDTC No.Trouble Area
(1) Open or short in heater circuit of main heated
oxygen sensor for 0.5 sec. or more.
(2) Main heated oxygen sensor signal voltage is
reduced to be 0.35 V and 0.70V for 60 sec.
under condition (a) ~ (d):
(2 trip detection logic)*1
(a) Engine coolant temp.: Between 80°C
(176°F) and 95°C (203°F)
(b) Engine speed: 1,500 rpm or more
(c) Load driving (Example A/T in
overdrive (5th for M/T), A/C ON, Flat
road, 80 km/h (50 mph))
(d) Main heated oxygen sensor signal
voltage: Alternating above and below
0.45V
Open or short in heater circuit of main heated
oxygen sensor
Main heated oxygen sensor heater
ECM
Main heated oxygen sensor circuit
Main heated oxygen sensor
DTC 21 Main Heated Oxygen Sensor Circuit
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±525