Ecm TOYOTA CAMRY 2000 Service Service Manual

REFERENCE VALUE OF ECM DATA
*1: If the engine coolant temp, sensor circuit is open or shorted, the ECM assumes an engine coolant temp, value of 80
C (176
F).
*2: When feedback control is forbidden, 0 V is displayed,
*3: A/T only.Closed throttle position
Wide open throttle
From closed throttle position to wide open throttle
When shifting from ªPº or ªNº position into a position
other than ªPº or ªNºEngine idling at normal operating temp.
increase engine loadEngine cold to hot
Engine idling at normal operating temp.
RPM stable at 2,500 rpm with normal operating temp.
PRM stable at 2,500 rpm with normal operating temp.RPM kept stable (Comparison with tachometer)
During driving (Comparison with speedometer)Below 5

Above 70

Gradually increases Approx. 180 ~ 280 mm Hg
Gradually increases
Engine idling at normal operating temp.Engine idling at normal operating temp.Gradually decreases
Approx. 2 ~ 5 msecs
REFERENCE VALUE
Engine at normal operating temp. 75 ± 95
C (185 ± 203
F) *1
Closed throttle position
RICH LEAN is repeated Increase engine speed
No large differences Inspection condition
Gradually increases
No great changes
2.50+ 1.25 V *2
During cranking
PNP SIGNAL *3A/C switch ON ENGINE SPEEDReference value
TARGET A/F LVEHICLE SPD
A/F FB LEFT
A/C SIGNALSTA SIGNAL
CTP SIGNAL30~60% INJECTOR
THROTTLEIAC DUTYIGNITION
G EAR MAPItem
OxLECT
HINT: ECM data can be monitored by TOYOTA hand±held
tester.
1. Hook up the TOYOTA hand±held tester to the DLC2.
2. Monitor ECM data by following the prompts on the tester
screen.
Please refer to the TOYOTA hand±held tester operator's
manual for further details.
± 5S±FE ENGINEREFERENCE VALUE OF ECM DATAEG1±326

MATRIX CHART OF PROBLEM SYMPTOMS
When the malfunction code is not confirmed in the diagnostic trouble code check and the problem still can
not be confirmed in the basic inspection, then proceed to this step and perform troubleshooting according
to the numbered order given in the table below.
*: Except California specification vehicles.
Park/Neutral position switch circuitManifold absolute pressure sensor circuit
VSV circuit for fuel pressure control
Ignition signal circuit (Spark test)
After acceleration pedal depressed
After acceleration pedal released
Switch condition signal circuit
Muffler explosion (after fire)No initial combustion
Back up power source circuit
Hesitation/Poor accelerationNo complete combustion
ECM power source circuit
Starter and Starter relay
Engine control module
High engine idle speed
Low engine idle speedUnder normal condition
During A/C operationEngine does not crank
A/C cut control circuit Starter signal circuit
Soon after starting
Fuel system circuit
When N to D shiftIncorrect first idle
Poor
Driveability
IAC valve circuit Difficult to
start
Injector circuit
Rough idling
Does not
start
Compression
Suspect area
Cold engine
Ignition coil Engine Stall
EG R system
Hot engine
Poor Idling
Spark plug
A/T faultylG±10,30*
IG±11,30 Distributor
Symptom
ST±19,21
See page
IG±8,28* IG±6,26*
Hunting
Surging
EG1±400
EG1±410 EG1±390
EG1±403
EG1±408
EG1±415
EG1±419EG1±383EG1±372
EG1±428EG1±396
EG1 ±424
AX1±68 EG1±23
IN±36
± 5S±FE ENGINEMATRIX CHART OF PROBLEM SYMPTOMSEG1±327

CIRCUIT DESCRIPTION
The distributor in the Engine Control System contains 3 pickup coils.
The G signals inform the ECM of the standard crankshaft position.
The NE signals inform the ECM of the crankshaft position and the engine speed.
wDuring cranking or idling, check waveforms
between terminals G (+) and G (±),
NE (+) and NE (±) of engine control module.
HINT: The correct waveforms appear as shown
in the illustration on the left.
wOpen or short in NE, G circuit
wDistributor
wOpen or short in STA circuit
wECM No G signal to ECM for 3 sec. or more with
engine speed between 600 rpm and 4,000 rpm. No N E signal to ECM with 2 sec. or more after
cranking.
CIRCUIT INSPECTION
INSPECTION USING OSCILLOSCOPE
Diagnostic Trouble Code Detecting Condition
Reference
Trouble Area
DTC 12 G NE Signal Circuit (No.1) (Exc. California spec.)
DTC No.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±336

Check for open and short in harness and
connector between ECM and distributor.Check resistance of each pickup coils in
distributor.
Repair or replace harness or connector.
DIAGNOSTIC CHART
WIRING DIAGRAM
Replace distributor housing.
Replace distributor housing.
Check and replace ECM. Check air gap.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±337

CIRCUIT DESCRIPTION
The distributor in the Engine Control System contains 3 pick±up coils (G1, G2 and NE).
The G1, G2 signals inform the ECM of the standard crankshaft angle.
The NE signals inform the ECM of the crankshaft angle and the engine speed.
wOpen or short in NE, G circuit.
wDistributor
wOpen or short in STA circuit.
wECM No NE or G1 and G2 signal to ECM for
2 sec. or more after cranking.Diagnostic Trouble Code Detecting Condition
Open in G (±) circuit.Trouble Area
DTC 12 G NE Signal Circuit (No.1) (Only for California spec.)
DTC No.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±339

Check for open and short in harness and
connector between ECM and distributor. Check resistance of each pickup coils in
distributor.
Repair or replace harness or connector.
DIAGNOSTIC CHART
WIRING DIAGRAM
Check and replace ECM.Replace distributor. Replace distributor.
Check air gap.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±340

*: Only for California specification vehicles.
CIRCUIT DESCRIPTION
Refer to G, NE signal circuit (No. 1) on page EG1±336, 339.
No G signal to ECM while N E signal is input 4
times to ECM when engine speed is between
500 rpm and 4,000 rpm.
* NE signal does not pulse 12 times to ECM
during the interval between G1 and G2 pulses.* No NE signal to ECM for 0.1 sec. or more at
1,000 rpm or more.No NE signal to ECM for 0.3 sec. or more at
1,500 rpm or more.
wOpen or short in NE circuit
wDistributor
wECM Diagnostic Trouble Code Detecting ConditionTrouble Area
DTC 13 G NE Signal Circuit (No.2)
DTC No.
DIAGNOSIS
This code indicates that a momentary interruption of the G, N E signal from the distributor to the
ECM has occurred, but that it is returned to normal. Note that although this problem may not nec-
essarily appear at the time of inspection, it cannot be ignored because this diagnostic trouble code
is output, indicating that there is or was a malfunction in the G, NE signal circuit; this ªmalfunctionº
is usually a loose connector.
The distributor connector and the N E terminal of the ECM connector must therefore be checked
for the following:
1. Loose connectors
2. Dirty connector terminals
3. Loose connector terminals
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±343

CIRCUIT DESCRIPTION
The ECM determines the ignition timing, turns on Tr, at a predetermined angle ('*CA) before the
desired ignition timing and outputs an ignition signal (IGT) ª1º 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, off and outputs the IGT signal ªOº.
This turns Tr2 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 lG F signal is not input to the ECM.
wOpen or short in IG F or IGT circuit from
igniter to ECM.
wIgniter
wECM No IGF signal to ECM for 4 (8*2) consecutive
IGT signals. Diagnostic Trouble Code Detecting Condition
WIRING DIAGRAM
Trouble Area
DTC 14 Ignition Signal Circuit
DTC No.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±344

Check for open and short in IGF signal circuit
between igniter and ECM.
Check for open and short in IGT signal circuit
between igniter and ECM. Check voltage of terminal IGT (Disconnect
igniter connector).Check for open and short in primary coil
circuit.Check and repair igniter power
source circuit.Repair or replace harness or
connector.
Repair or replace harness or
connector.
Repair or replace harness or
connector. Check voltage of igniter power source.
DIAGNOSTIC CHART
Check voltage of terminal I G F.
Check voltage of terminal IGT.
Check and replace ECM.Check and replace ECM.
Replace ignition coil.
Check ignition coil.Check for spark.
Replace igniter.
Replace igniter.
Replace igniter.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±345

CIRCUIT DESCRIPTION
The signal from the A/T CPU retards the ignition timing of the engine during A/T shifting, thus
momentarily reducing torque output of the engine for smooth clutch operation inside the transmis-
sion and reduced shift shock.
If the ECM detects the diagnostic trouble code ª16º in memory, it prohibits the torque control of the
A/T which performs smooth gear shifting.
Are there any other codes (besides Code 16)
being output?Fault in communications between the engine
CPU and A/T CPU in the ECM
Go to relevant diagnostic trouble code
chart. Diagnostic Trouble Code Detecting Condition
DIAGNOSTIC CHART
Replace ECM.Trouble Area
DTC 16 A±T Control Signal Malfunction
DTC No.
wECM
YES
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±351