TOYOTA CAMRY 1999 Service Repair Manual

± DIAGNOSTICSENGINE (1MZ±FE)
DI±269
504 Author: Date:
4 Check for spark and ignition (See page IG±1).
NG Repair or replace.
OK
5 Check fuel pressure (See page SF±21).
NG Check and repair fuel pump, pressure regulator,
fuel pipe line and filter (See page SF±1).
OK
6 Check gas leakage on exhaust system.
NG Repair or replace.
OK

DI±270
± DIAGNOSTICSENGINE (1MZ±FE)
505 Author: Date:
7 Check the output voltage A/F sensors (bank1, 2 sensor1).
PREPARATION:
(a) Connect the OBDII scan tool or TOYOTA hand±held tester to the DLC3.
(b) Warm up the A/F sensors (bank1, 2 sensor1) with the engine at 2,500 rpm for approx. 90 sec.
CHECK:
Read voltage value of A/F sensors (bank1, 2 sensor1) on the screen of OBDII scan tool or TOYOTA hand±
held tester when you perform all the following conditions.
HINT:
The voltage of AFR
, AFL
terminal of ECM is 3.3 fixed AFR, AFL terminal is 3.0 V fixed. Therefore,
it is impossible to check the A/F sensors (bank1, 2 sensor1) output voltage at the terminals (AFR
, AFL
/
AFR, AFL) of ECM.
OK:
ConditionA/F Sensor Voltage value
Engine idling
Engine racing
Not remains at 3.30 V (*0.660 V)

Notremainsat38V(*076V)ormoreDriving at engine speed 1,500 rpm or more and vehicle
speed 40 km/h (25mph) or more, and operate throttle valve
open and close
Not remains at 3.8 V (*0.76 V) or more

Not remains at 2.8 V (*0.56 V) or less
*: When you use the OBDII scan tool (excluding TOYOTA hand±held tester)
HINT:

During fuel enrichment, there is a case that the output voltage of A/F sensors (bank1, 2 sensor1) is
below 2.8 V (*0.56 V), it is normal.

During fuel cut, there is case that the output voltage of A/F sensors (bank1, 2 sensor1) is above 3.8
V (*0.76 V), it is normal.

If output voltage of A/F sensors (bank1, 2 sensor1) remains at 3.30 V (*0.660 V) even after performing
all the above conditions, A/F sensors (bank1, 2 sensor1) circuit may be open.

If output voltage of A/F sensors (bank1, 2 sensor1) remains at 3.8 V (*0.76 V) or more, or 2.8 V (*0.56
V) or less even after performing all the above conditions, A/F sensors (bank1, 2 sensor1) circuit may
be short.
*: When you use the OBDII scan tool (excluding TOYOTA hand±held tester).
OK Go to step 9.
NG

± DIAGNOSTICSENGINE (1MZ±FE)
DI±271
506 Author: Date:
8 Check for open and short in harness and connector between ECM and A/F sen-
sors (bank1, 2 sensor1) (See page IN±31).
NG Repair or replace harness or connector.
OK
Replace A/F sensors (bank1, 2 sensor1).
9 perform confirmation driving pattern (See page DI±340).
Go
10 Is there DTC P0171 or P0172 being output again ?
YES Check and replace ECM
(See page IN±31).
NO
11 Did vehicle runs out of fuel in the past ?
NO Check for intermittent problems
(See page DI±197).
YES
DTC P0171 or P0172 is caused by running out of fuel.

DI±272
± DIAGNOSTICSENGINE (1MZ±FE)
507 Author: Date:
DTC P0171 System too Lean (Fuel Trim)
(Except California Spec.)
DTC P0172 System too Rich (Fuel Trim)
(Except California Spec.)
CIRCUIT DESCRIPTION
Fuel trim refers to the feedback compensation value compared against the basic injection time. Fuel trim
includes short±term fuel trim and long±term fuel trim.
Short±term fuel trim 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.
Long±term fuel trim is overall fuel compensation carried out long±term to compensate for continual deviation
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
detected as a malfunction and the MIL lights up.
DTC No.DTC Detecting ConditionTrouble Area
P0171
When air fuel ratio feedback is stable after engine warming up,
fuel trim is considerably in error on RICH side
(2 trip detection logic)

Air intake (hose loose)

Fuel line pressure

Injector blockage

Heated oxygen sensors (bank 1, 2 sensor 1) malfunction

Mass air flow meter

Engine coolant temp. sensor

Gas leakage on exhaust system
P0172
When air fuel ratio feedback is stable after engine warming up,
fuel trim is considerably in error on LEAN side
(2 trip detection logic)

Fuel line pressure

Injector leak, blockage

Heated oxygen sensors (bank 1, 2 sensor 1) malfunction

Mass air flow meter

Engine coolant temp. sensor

Gas leakage on exhaust system
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 % (80°C (176°F)
or more), the system is functioning normally.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining
whether the vehicle was running or stopped, the engine warmed up or not, the air±fuel ratio lean or rich, etc.
at the time of the malfunction.
DI4DR±01

± DIAGNOSTICSENGINE (1MZ±FE)
DI±273
508 Author: Date:
1 Check air induction system (See page SF±1).
NG Repair or replace.
OK
2 Check injector injection (See page SF±21).
NG Replace injector.
OK
3 Check mass air flow meter and engine coolant temp. sensor
(See pages SF±35 and SF±63).
NG Repair or replace.
OK
4 Check for spark and ignition (See page IG±1).
NG Repair or replace.
OK
5 Check fuel pressure (See page SF±6).
NG Check and repair fuel pump, pressure regulator,
fuel pipe line and filter.
OK

P18349
DI±274
± DIAGNOSTICSENGINE (1MZ±FE)
509 Author: Date:
6 Check gas leakage on exhaust system.
NG Repair or replace.
OK
7 Check the output voltage of heated oxygen sensors (bank1, 2 sensor1) during
idling.
PREPARATION:
Warm up the heated oxygen sensors (bank1, 2 sensor1) the engine at 2,500 rpm for approx. 90 sec.
CHECK:
Use the OBDII scan tool or TOYOTA hand±held tester to read the output voltage of the heated oxygen sen-
sors (bank1, 2 sensor1) during idling.
OK:
Heated oxygen sensors (bank1, 2 sensor1) output voltage:
Alternates repeatedly between less than 0.4 V and more than 0.55 V (See the Following table).
OK Go to step 9.
NG

± DIAGNOSTICSENGINE (1MZ±FE)
DI±275
510 Author: Date:
8 Check for open and short in harness and connector between ECM and heated
oxygen sensors (bank1, 2 sensor1) (See page SF±71).
NG Repair or replace harness or connector.
OK
Replace heated oxygen sensors
(bank1, 2 sensor1).
9 Perform confirmation driving pattern (See page DI±255).
Go
10 Is there DTC P0171 or P0172 being output again ?
YES Check and replace ECM.
NO
11 Did vehicle runs out of fuel in the past ?
NO Check for intermittent problems.
YES
DTC P0171 or P0172 is caused by running out of fuel.

DI±276
± DIAGNOSTICSENGINE (1MZ±FE)
511 Author: Date:
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 any
particular 200 or 1,000 revolutions
Ignition system

Injector

Fuel line pressure
P0301
P0302
P0303For any particular 200 revolutions for engine, misfiring is de-
tected which can cause catalyst overheating
(This causes MIL to blink)

EGR

Compression pressure

Valve clearance not to specification

Valve timing

Mass air flow meterP0303
P0304
P0305
P0306For any particular 1,000 revolutions of engine, misfiring is de-
tected which causes a deterioration in emission
(2 trip detection logic)

Mass air flow meter

Engine coolant temp. sensor

Open or short in engine wire

Connector connection

ECM
DI07S±07

A03319
Instrument
Panel J/B
Engine
Room
J/B
N0.2
BatteryFL
MAINB±GB±R B±R
B±R
W±RJ18
Junction
Connector
B±R
B±R
B±R
B±R
B±R
B±R2
2
2
2
2
21
1
1
1
1
1L
R
Y
W
R±L
GE10
Ignition
Switch
No. 1
No. 2
No. 3
No. 4
No. 5
No. 6
Injector
BR
BR
EC
II3
5
6
21
311
2
3
4#10
#20
#30
#40
#50
#60
E01
E02ECM
12
2L
2A
AM2
4
1
B
F4F6 11 6
7
1K 1K 1C
1B 38
55
W±RE10
E11
E11
E11
E11
E11
E11 Fusible
Link
Block
± DIAGNOSTICSENGINE (1MZ±FE)
DI±277
512 Author: Date:
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.
WIRING DIAGRAM
CONFIRMATION DRIVING PATTERN
(1) Connect the TOYOTA hand±held tester or OBD II scan tool.
(2) Record DTC and the freeze frame data.
(3) Use the TOYOTA hand±held tester to set to Check Mode. (See page DI±197)
(4) Drive the vehicle several times with the engine speed, load and its surrounding range shown with
ENGINE SPD, CALC LOAD in the freeze frame data or MISFIRE RPM, MISFIRE LOAD in the data list.
If you have no TOYOTA hand±held tester, turn the ignition switch OFF after the symptom is simulated
the first time. Then repeat the simulation process again.
HINT:
In order to memorize DTC of misfire, it is necessary to drive around MISFIRE RPM, MISFIRE LOAD in the
data list for the following period of time.
Engine SpeedTime
Idling3 minutes 30 seconds or more
1000 rpm3 minutes or more
2000 rpm1 minute 30 seconds or more
3000 rpm1 minute or more
(5) Check whether there is misfire or not by monitoring DTC and the freeze frame data. After that, record
them.
(6) Turn ignition switch OFF and wait at least 5 seconds.

DI±278
± DIAGNOSTICSENGINE (1MZ±FE)
513 Author: Date:
INSPECTION PROCEDURE
HINT:

If is the case that DTC besides misfire is memorized simultaneously, first perform the troubleshooting
for them.

Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame
data records the engine conditions when the malfunction is detected, when troubleshooting it is useful
for determining whether the vehicle was running or stopped, the engine warmed up or not, the air±fuel
ratio lean or rich, etc. at the time of the malfunction.

When the vehicle is brought to the workshop and the misfire is not occurred, misfire can be confirmed
by reproducing the condition or freeze frame data. Also, after finishing the repair, confirm that there
is no misfire. (See the confirmation driving pattern)

When either of SHORT FT #1, LONG FT #1, SHORT FT #2 or LONG FT #2 in the freeze frame data
is besides the range of ±20%, there is a possibility that the air±fuel ratio is inclining either to ºrichº
(±20% or less) or ºleanº (+20% or more).

When COOLANT TEMP in the freeze frame data is less than 80°C (176°F), there is a possibility or
misfire only during warming up.

In the case that misfire cannot be reproduced, the reason may be because of the driving with lack or
fuel, the use of improper fuel, a stain of ignition plug, and etc.
1 Check wire harness, connector and vacuum hose in engine room.
CHECK:
(a) Check the connection conditions of wire harness and connector.
(b) Check the disconnection, piping and break of vacuum hose.
NG Repair or replace, then confirm that there is no
misfire (See the confirmation driving pattern).
OK