fuse TOYOTA TERCEL 1996 Service User Guide

A15689
FI7052
DI-34
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
If DTC P0105, P0110, P0120 are output simultaneously, E2 (sensor ground) may be open.
1 Connect OBD II scan tool or TOYOTA hand-held tester and read throttle valve
opening percentage.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the OBD II scan tool or TOYOTA hand-held tes-
ter to the DLC3.
(c) Turn the ignition switch ON and OBD II scan tool or TOY-
OTA hand-held tester main switch ON.
CHECK:
Read the throttle valve opening percentage.
OK:
Throttle valveThrottle valve opening
position expressed as percentage
Fully openApprox. 70 %
Fully closedApprox. 10 %
OK Check for intermittent problems
(See page DI-3).
NG

A15693
- DIAGNOSTICSENGINE
DI-39
1996 TERCEL (RM440U)
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Connect OBD II scan tool or TOYOTA hand-held tester and read value for volt-
age output of heated oxygen sensor.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect OBD II scan tool or TOYOTA hand-held tester to the DLC3.
(c) Warm up the engine to the normal operating temperature.
CHECK:
Read the voltage output of the heated oxygen sensor (bank 1 sensor 1) when the engine is suddenly raced.
HINT:
Perform quick racing to 4,000 rpm 3 times using accelerator pedal.
OK:
Heated oxygen sensor output a RICH signal (0.45 V or more) at least once.
OK Check and replace ECM (See page IN-26).
NG
2 Check for open and short in harness and connector between ECM and oxygen
sensor (See page IN-26).
NG Repair or replace harness or connector.

DI-42
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
INSPECTION PROCEDURE
1 Check for open and short in harness and connector between ECM and oxygen
sensor (See page IN-26).
NG Repair or replace harness or connector.
OK
2 Check for oxygen sensor data.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC3.
(c) Warm up engine to normal operating temperature.
CHECK:
Read the oxygen sensor output voltage and short-term fuel trim.
RESULT:
PatternOxygen sensor output voltageShort-term fuel trim
1Lean condition (Changes at 0.55 V or less)Changes at about +20 %
2Rich condition (Changes at 0.4 V or more)Changes at about -20 %
3Except 1 and 2
1, 2 Check fuel trim system (See page DI-49).
3

DI-46
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
3 Check output voltage of heated oxygen sensor (bank 1 sensor 2).
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC3.
(c) After warming up the engine, race the engine at 2,500 rpm for 3 minutes.
CHECK:
Read the output voltage of the heated oxygen sensor (bank 1 sensor 2) when racing the engine after 3 min-
utes have elapsed.
OK:
Heated oxygen sensor output voltage: Alternates from 0.4 V or less to 0.5 V or more.
OK Check that each connector is properly
connected.
NG
Replace heated oxygen sensor.

DI-50
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
INSPECTION PROCEDURE
1 Check air induction system (See page MF-1).
NG Repair or replace.
OK
2 Check for heated oxygen sensor data.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC3.
(c) Warm up engine to normal operating temperature.
CHECK:
Read the oxygen sensor output voltage and short-term fuel trim.
RESULT:
PatternOxygen sensor output voltageShort-term fuel trim
1Lean condition (Changes at 0.55 V or less)Changes at about + 20 %
2RIch condition (Changes at 0.4 V or more)Changes at about - 20 %
3Except 1 and 2
3 Check for oxygen sensor
(See page DI-41).
1, 2
3 Check fuel pressure (See page MF-1).
NG Check and repair fuel pump, pressure regulator,
fuel pipe line and filter. (See page MF-5)
OK

P20272A04988
Engine Room R/B
EFI Fuse
- DIAGNOSTICSENGINE
DI-93
1996 TERCEL (RM440U)
2 Check EFI fuse.
PREPARATION:
Remove the EFI fuse from the engine room R/B.
CHECK:
Check the continuity of the EFI fuse.
OK:
Continuity
NG Check for short in all harness and components
connected to EFI fuse.
OK
Check and repair harness or connector
between battery, EFI fuse and ECM

DI-94
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
DTC P1780 Park/Neutral Position Switch Malfunction
CIRCUIT DESCRIPTION
The park/neutral position switch goes on when the shift lever is in the N or P shift position. When it goes on
terminal NSW of the ECM is grounded to body ground via the starter relay thus the terminal NSW voltage
becomes 0 V. When the shift lever is in the D, 2, L or R position, the park/neutral position switch goes off,
so the voltage of ECM terminal NSW becomes battery positive voltage, the voltage of the ECM internal pow-
er source.
If the shift lever is moved from the N position to the D position, this signal is used for air-fuel ratio correction
and for idle speed control (estimated control), etc.
DTC No.DTC Detection ConditionTrouble Area
P1780
When driving under conditions (a) and (b) for 30 seconds or
more, the park/neutral position switch is ON (N position)
(2 trip detection logic)
(a) Vehicle speed: 80 km/h (50 mph) or more
(b) Engine speed: 2,000 - 3,000 rpm

Short in park/neutral position switch circuit

Park/neutral position switch

ECM
HINT:

After confirming DTC P1780, use the TOYOTA hand-held tester to confirm the PNP switch signal from
the CURRENT DATA.

After confirming DTC P1780, in the case that the diagnostic trouble codes are erased by disconnecting
the battery terminals or EFI fuse, after operating the shift lever few times from P or N position to D posi-
tion, confirm the PNP switch signal using the CURRENT DATA of the TOYOTA hand-held tester. If
the PNP switch signal is not displayed on TOYOTA hand-held tester, the circuit of PNP switch signal
may be short.
DI3A1-04

A15735
DI-98
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
INSPECTION PROCEDURE
1 Check voltage between terminals +B and E1 of ECM connector.
PREPARATION:
(a) Remove the lower finish panel.
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals +B and E1 of the ECM
connectors.
OK:
Voltage: 9 - 14 V
OK Proceed to next circuit inspection shown on
matrix chart (See page DI-19).
NG
2 Check for open in harness and connector between terminal E1 of ECM and body
ground (See page IN-26).
NG Repair or replace harness or connector.
OK
3 Check EFI main relay (Marking: EFI) (See page MF-38).
NG Replace EFI main relay.
OK
4 Check EFI fuse (See page DI-92, step 2).
NG Check for short in all harness and components
connected to EFI fuse.
OK

- DIAGNOSTICSENGINE
DI-99
1996 TERCEL (RM440U)
5 Check for open in harness and connector between EFI main relay (Marking: EFI)
and battery, EFI main relay (Marking: EFI) and ECM (See page IN-26).
NG Repair or replace harness or connector.
OK
6 Check IGN fuse of driver side J/B.
NG Check for short in all harness and components
connected to IGN fuse.
OK
7 Check ignition switch (See page BE-1 1).
NG Replace ignition switch.
OK
Check for open in harness and connector between ignition switch and EFI main relay, EFI main
relay and body ground (See page IN-26).

A15740
DI-106
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
A/C Cut Control Circuit
CIRCUIT DESCRIPTION
This circuit cuts air conditioning operation during vehicle acceleration in order to increase acceleration per-
formance. During acceleration with the vehicle speed at 25 km/h (16 mph) or less, engine speed at 1,200
rpm or less and throttle valve opening angle at 50° or more, the A/C magnet switch is turned OFF for several
seconds.
WIRING DIAGRAM
INSPECTION PROCEDURE
TOYOTA hand-held tester:
1 Connect TOYOTA hand-held tester and check operation of air conditioning cut
control.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the TOYOTA hand-held tester to the DLC3.
(c) Turn ignition switch ON and TOYOTA hand-held tester main switch ON.
(d) Start the engine and air conditioning switch ON.
HINT:
A/C magnet clutch is turned ON.
(e) Select the ACTIVE TEST mode on the TOYOTA hand-held tester.
CHECK:
Check operation of A/C magnet clutch cut when air conditioning cut control is operated by the TOYOTA
hand-held tester.
OK:
A/C magnet clutch is turned OFF
OK Proceed to next circuit inspection shown on
matrix chart (See page DI-19).
DI1EK-09