TOYOTA PREVIA 91-97 REPAIR MANUAL

4-34 DRIVEABILITYANDEMI

2TZ-FZE ENGINE

Engine and Automatic Transmission

» See Figure 106

The OBDII scan tool can clear DTCs, refer to the owners manual
to the next few steps.
After repair of the circuit, the diagnostic code(s) must be remove
:he ECM memory. With the ign tion turned OFF, remove the 15 am
fuse for 30 seconds or more. Once the time period has been observ
reinstall the fuse and check for normal code output.
If the diagnostic code is not erased, it will be retained by the EC
appear along with a new code in event of future trouble.
Cancellation of the trouble code can also be accomplished by d ;
necting the negative battery cable. However, disconnecting the batte
will erase the other memory systems including the clock and radio :
If this method is used, always reset these components once the trot
code has been erased.

Fig. 107 Engine diagnostic

DIAGNOSTIC CODES

HINT: • If a malfunction is detected

the table, and turn to the corr

• Your readings may vary fror
  used.
  Code
  No.


• 
  

12

13

14

21

22

24

25

26

Numberblinks of

angina"CHECK" warn-

ing light

_nnnn/uuin_

-JUHL

_JUIM

-juum

in n

TlJUIL

.JUl.'lM

_«*

_„«

System

Normal

RPM

Signal

RPM

Signal

Ignition

Signal

Main

OxygenSensor

Main

Oxygen

SensorHeater

Water

Temp.

Intake

AirTemp.

Signal

Air-FuelRatio

Lean Maf-

Air-Fual

RatioRich

Mai-

"CHECK""1

WarningEngine

Light

• 
  

ON

ON

ON

ON

ON

ON

•3

ON

ON

ON

Outpu

No "NE

sees, a

NE 59

IGFsg

ECU to

At nor

duced

for 60•6 (2

Openo

for 500

Open o

for 500

(1) (^0) fo
sp
(2) W
n
•6 (2
codes— 2TZ-FE engine
SSIONS CONTROLS
or refer /
from |S2^
EFI ^n -
d
land
con-
y cable
ettings.
-HS^
§L-^:
S^sJ T\ EFI (15A|
j '
ii-, 1 ii ii ir~T~ii !L_J1 II IL r -^ TT ;-
i crr3crz:c^;c^z]ci3C^czDCz:c u '
' J
)|g 90914GB3
Fig. 106 The EFI fuse is located in the fuse box in the dash,
check your owners manual for exact position
uring the diagnostic code check, refer to the circuit indicated in
spending page,
the parameters listed in the chart depending on the instruments
Diagnosis
when no other code is recorded.
or '0' signal is input to the ECU for 2
more after STA turns ON.
I is not input lo ECU for 0.3 sec. or
len engine speed is 1,000 rpm or
a from igniter is not input to
3 driving speed (below 60 mph and
peed is above t,700 rprn). amplitude
oxygenbetween sensor signal 0.35 - 0.70 V (OX1) continuously is re-
rp detection logic) (2)
short in heater circuit of main
isec. or more. (THW
ts«c. or more. (THA
genit least sensor output 90 sees, when is less than 0.45 oxygen sensor V
V armed up. (Only for code 25 in Calif,
:.)
|C°F)the or coolant abo^e. temperature of 60°C
ip detection logic) (1 and (2)
Trouble Area
~

• OpenDistributor orstion in NE circuit


• Igniter circuit


• igniter
  . ECU


• Open or short in NE circuit


• Distributor


• ECU

circuit from igniter to ECU

• ECU

oxygen sensor circuit

Main oxygen sensor

• ECU


• Open or short in heater cir-


• ECU


• Open or short in water


• Water temp, sensor


• ECU


• Open or short in intake air


• Intaketemp, circuit air temp, sensor


• ECU


• Open in El circuit


• Open in injector circuit


• Fuel lineblockage, pressure etc.* (Injector
  Open or short in oxygen


• Air flow meter (Air intake!


• ECU


• • Open Open in m El injector circuit circuit
  Fuelleakage, ling etc.) pressure (Injector

Cold start injector

• Oxygen sensor


• Air flow meter


• ECU

Memory•2

• C O C o ° o 0 0

90914G98