1996 TOYOTA TERCEL Service Repair Manual

FI0534
DI4LE-02
P19552
TOYOTA Hand-Held Tester
DLC3
- DIAGNOSTICSENGINE
DI-3
1996 TERCEL (RM440U)
PRE-CHECK
1. DIAGNOSIS SYSTEM
(a) Description

When troubleshooting OBD II vehicles, the only dif-
ference from the usual troubleshooting procedure
is that you need to connect OBD II scan tool comply-
ing with SAE 1978 or TOYOTA hand-held tester to
the vehicle and read off various data output from the
vehicle's ECM.

OBD II regulations require that the vehicle's on-
board computer lights up the Malfunction Indicator
Light (MIL) on the instrument panel when the com-
puter detects a malfunction in the computer itself or
in a drive system components which affect vehicle
emissions. In addition to the MIL lighting up when
a malfunction is detected, the applicable Diagnostic
Trouble Code (DTC) prescribed by SAE J2012 are
recorded in the ECM memory (See page DI-13).
If the malfunction does not reoccur in 3 trips, the MIL goes off
but the DTC remain recorded in the ECM memory.

To check the DTC, connect the OBD II scan tool or
TOYOTA hand-held tester to Data Link Connector
3 (DLC3) on the vehicle. The OBD II scan tool or
TOYOTA hand-held tester also enables you to
erase the DTC and check freezed frame data and
various forms of engine data (For operating instruc-
tions, see the OBD II scan tool's instruction book.).

DTC include SAE controlled codes and manufac-
turer controlled codes. SAE controlled codes must
be set as prescribed by the SAE, while manufactur-
er controlled codes can be set freely by the
manufacturer within the prescribed limits (See DTC
chart on page DI-13).

N09214
DTC3 DI-4
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)

The diagnosis system operates in normal mode
during normal vehicle use. It also has a check mode
for technicians to simulate malfunction symptoms
and troubleshoot. Most DTC use 2 trip detection
logic* to prevent erroneous detection, and ensure
thorough malfunction detection. By switching the
ECM to check mode when troubleshooting, the
technician can cause the MIL to light up for a mal-
function that is only detected once or momentarily
(TOYOTA hand-held tester only) (See page
DI-3).

*2 trip detection logic:
When a logic malfunction is first detected, the mal-
function is temporarily stored in the ECM memory.
If the same malfunction is detected again during the
second drive test, this second detection causes the
MIL to light up.

The 2 trip repeats the same mode a 2nd time (How-
ever, the IG switch must be turned OFF between the
1st trip and 2nd trip.).

Freeze frame data:
Freeze frame data records the engine condition
when a misfire (DTC P0300 - P0304) or fuel trim
malfunction (DTC P0171, P0172) or other malfunc-
tion (first malfunction only), is detected, as freeze
frame data records the engine conditions (fuel sys-
tem, calculator load, engine coolant temperature,
fuel trim,engine speed, vehicle speed, etc.) 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.
Priorities for troubleshooting:
If troubleshooting priorities for multiple DTC are given in the ap-
plicable DTC chart, these should be followed.
If no instructions are given troubleshoot DTC according to the
following priorities.
(1) DTC other than fuel trim malfunction (DTC P0171,
P0172) and misfire (DTC P0300 - P0304).
(2) Fuel trim malfunction (DTC P0171, P0172).
(3) Misfire (DTC P0300 - P0304).
(b) Check the DLC3.
The vehicle's ECM uses ISO 9141-2 for communication.
The terminal arrangement of DLC3 complies with SAE
J1962 and matches the ISO 9141-2 format.

S00840
- DIAGNOSTICSENGINE
DI-5
1996 TERCEL (RM440U)Terminal No.
Connection / Voltage or ResistanceCondition
7Bus + Line / Pulse generationDuring transmission
4Chassis Ground - Body Ground / 1 W or lessAlways
5Signal Ground - Body Ground / 1 W or lessAlways
16Battery Positive - Body Ground / 9 - 14 VAlways
HINT:
If your display shows ºUNABLE TO CONNECT TO VEHICLEº
when you have connected the cable of the OBD II scan tool or
TOYOTA hand-held tester to DLC3, turned the ignition switch
ON and operated the scan tool, there is a problem on the ve-
hicle side or tool side.

If communication is normal when the tool is connected to
another vehicle, inspect DLC3 on the original vehicle.

If communication is still not possible when the tool is con-
nected to another vehicle, the problem is probably in the
tool its self, so consult the Service Department listed in
the tool's instruction manual.
2. Normal Mode:
INSPECT DIAGNOSIS
(a) Check the MIL.
(1) The MIL comes on when the ignition switch is turned
ON and the engine is not running.
HINT:
If the MIL does not light up, troubleshoot the combination meter.
(2) When the engine started, the MIL should go off. If
the lamp remains on, the diagnosis system has de-
tected a malfunction or abnormality in the system
(b) Check the DTC.
NOTICE:
TOYOTA hand-held tester only: When the diagnosis sys-
tem is switched from the normal mode to the check mode,
it erases all DTC and freeze frame data recorded in the nor-
mal mode. So before switching modes, always check the
DTC and freeze frame data, and note them down.
(1) Prepare the OBD II scan tool (complying with SAE
J 1978) or TOYOTA hand-held tester.
(2) Connect the OBD II scan tool or TOYOTA hand-
held tester to DLC3 in the fuse box at the lower left
of the instrument panel.
(3) Turn the ignition switch ON and turn the OBD II scan
tool or TOYOTA hand-held tester switch ON.
(4) Use the OBD II scan tool or TOYOTA hand-held
tester to check the DTC and freezed frame data;
note them down (For operating instructions, see the
OBD II scan tool's instruction book.).
(5) See page DI-13 to confirm the details of the
DTC.

FI3605
Flashing
ON
OFF
0.13 Seconds
DI-6
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
NOTICE:
When simulating symptoms with an OBD II scan tool (ex-
cluding TOYOTA hand-held tester) to check the DTC, use
the normal mode. For code on the DTC chart subject to º2
trip detection logicº, turn the ignition switch OFF after the
symptom is simulated the first time. Then repeat the simu-
lation process again. When the problem has been simu-
lated twice, the MIL lights up and the DTC are recorded in
the ECM.
3. Check Mode:
INSPECT DIAGNOSIS
HINT:
TOYOTA hand-held tester only:
Compared to the normal mode, the check mode has an in-
creased sensitivity to detect malfunctions.
Furthermore, the same diagnostic items which are detected in
the normal mode can also be detected in the check mode.
(a) Check the DTC.
(1) Initial conditions.

Battery positive voltage 11V or more.

Throttle valve fully closed.

Transmission in ºPº or ºNº position.

Air conditioning switched OFF.
(2) Turn the ignition switch OFF.
(3) Prepare the TOYOTA hand-held tester.
(4) Connect the TOYOTA hand-held tester to DLC3 in
the fuse box at the lower left of the instrument panel.
(5) Turn the ignition switch ON and switch the TOYOTA
hand-held tester ON.
(6) Switch the TOYOTA hand-held tester normal mode
to check mode. (Check that the MIL flashes.)
(7) Switch the engine. (The MIL goes out after the en-
gine start.)
(8) Simulate the conditions of the malfunction de-
scribed by the customer.
NOTICE:
Leave the ignition switch ON until you have checked the
DTC, etc.
(9) After simulating the malfunction conditions, use the
TOYOTA hand-held tester diagnosis selector to
check the DTC and freezed frame data, etc.
HINT:
Take care not to turn the ignition switch OFF. Turning the ignition
switch OFF switches the diagnosis system from check mode to
normal mode, so all DTC, etc. are erased.
(10) After checking the DTC, inspect the applicable cir-
cuit.

- DIAGNOSTICSENGINE
DI-7
1996 TERCEL (RM440U)
(b) Clear the DTC.
The following actions will erase the DTC and freezed
frame data.
(1) Operating the OBD II scan tool (complying with SAE
J1978) or TOYOTA hand-held tester to erase the
codes. (See the OBD II scan tool's instruction book
for operating instructions.)
(2) Disconnecting the battery terminals or EFI fuse.
NOTICE:
If the TOYOTA hand-held tester switches the ECM from
normal mode to check mode or vice-versa, or if the igni-
tion switch is turned from ON to ACC or OFF during check
mode, the DTC and freezed frame data will be erased.
4. FAIL-SAFE CHART
If any of the following codes is recorded, the ECM enters fail-safe mode.
DTC No.Fail-Safe OperationFail-Safe Deactivation Conditions
P0105Ignition timing fixed at 5° BTDCReturned to normal condition
P0110Intake air temp. is fixed at 20°C (68°F)Returned to normal condition
P0115Engine coolant temp. is fixed at 80°C (176°F)Returned to normal condition
P0120VTA is fixed at 0°
The following condition must be repeated at least 2 times
consecutively
When closed throttle position switch is ON:
0.1 V
VTA
0.95 V
P0141The heater circuit in which an abnormality is detected is
turned offIgnition switch OFF
P0325Max. timing retardationIgnition switch OFF
P1300Fuel cutIGF signal is detected for 4 consecutive ignitions
5. CHECK FOR INTERMITTENT PROBLEMS
HINT:
TOYOTA hand-held tester only:
By putting the vehicle's ECM in check mode, 1 trip detection logic is possible instead of 2 trip detection logic
and sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.
(a) Clear the DTC (See page DI-13).
(b) Set the check mode (See page DI-13).
(c) Perform a simulation test (See page IN-26).
(d) Check the connector and terminal (See page IN-26).
(e) Handle the connector (See page IN-26).
6. BASIC INSPECTION
When the malfunction code is not confirmed in the DTC check, troubleshooting should be performed in the
order for all possible circuits to be considered as the causes of the problems. In many cases, by carrying
out the basic engine check shown in the following flow chart, the location causing the problem can be found
quickly and efficiently. Therefore, use of this check is essential in engine troubleshooting.
1 Is battery positive voltage 11V or more when engine is stopped ?
NO Charge or replace battery.

MA0659
Outside
Inside
DI-8
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
YES
2 Is engine cranked ?
NO Proceed to ST-13, ST-28, ST-31 and continue
to troubleshoot.
YES
3 Does engine start ?
NO Go to step 7.
YES
4 Check air filter.
PREPARATION:
Remove the air filter.
CHECK:
Visual check that the air cleaner element is not excessively dirty
or oily.
HINT:
If necessary, clean the filter with compressed air. First blow from
inside thoroughly, then blow from outside of filter.
NG Repair or replace.
OK
5 Check engine idle speed.
PREPARATION:
(a) Warm up engine to normal operating temperature.
(b) Switch off all accessories.
(c) Switch off air conditioning.
(d) Shift transmission into ºNº position.

P25914P25915A07081
TE1
E1 SST
DLC1
- DIAGNOSTICSENGINE
DI-9
1996 TERCEL (RM440U)
(e) Remove the fuse cover on the instrument panel.
(f) Connect the OBD II scan tool or TOYOTA hand-held tester to DLC3 on the vehicle.
CHECK:
Use CURRENT DATA to check the engine idle speed.
OK:
Idle speed: 700 - 800 rpm
NG Proceed to matrix chart of problem symptoms
on page DI-19.
OK
6 Check ignition timing.
PREPARATION:
(a) Warm up engine to normal operating temperature.
(b) Shift transmission into ºNº position.
(c) Keep the engine speed at idle.
(d) Using SST, connect terminals TE1 and E1 of DLC1.
SST 09843-18020
(e) Using a timing light, connect the tester to No.1 high-ten-
sion cord.
CHECK:
Check ignition timing.
OK:
Ignition timing: 10° BTDC at idle
NG Proceed to page IG-1 and continue to trouble-
shoot.
OK
Proceed to matrix chart of problem symp-
toms on page DI-19.

P25916
S00553
DI-10
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
7 Check fuel pressure.
PREPARATION:
(a) Be sure that enough fuel is in the tank.
(b) Turn ignition switch ON.
(c) Remove the fuse cover on the instrument panel.
(d) Connect the TOYOTA hand-held tester to DLC3 on the
vehicle.
(e) Use ACTIVE TEST mode to operate the fuel pump.
(f) If you have no TOYOTA hand-held tester, connect the
positive (+) and negative (-) leads from the battery to the
fuel pump connector (See page MF-1).
CHECK:
Check for fuel pressure in the inlet hose when it is pinched off.
HINT:
At this time, you will hear a fuel flowing noise.
NG Proceed to page MF-1 and continue to trouble-
shoot.
OK
8 Check for spark.
PREPARATION:
(a) Disconnect the high-tension cord from spark plug or re-
move the ignition coil.
(b) Remove spark plug.
(c) Install the spark plug to high-tension cord or ignition coil.
(d) Disconnect injector connector.
(e) Ground the spark plug.
CHECK:
Check if spark occurs while engine is being cranked.
NOTICE:
To prevent excess fuel being injected from the injectors
during this test, do not crank the engine for more than 5 -
10 seconds at a time.
NG Proceed to page IG-1 and continue to trouble-
shoot.
OK