relay TOYOTA TERCEL 1996 Service User Guide

- DIAGNOSTICSENGINE
DI-91
1996 TERCEL (RM440U)
INSPECTION PROCEDURE
HINT:
This diagnostic chart is based on the premise that the engine is cranked normally. If the engine is not
cranked, proceed to the problem symptoms table on page DI-19.
1 Connect TOYOTA hand-held tester, and check STA signal.
PREPARATION:
(a) Connect the TOYOTA hand-held tester to the DLC3.
(b) Turn the ignition switch ON and push the TOYOTA hand-held tester main switch ON.
CHECK:
Read the STA signal on the TOYOTA hand-held tester while the starter operates.
OK:
Ignition Switch PositionONSTART
STA SignalOFFON
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI-19).
NG
2 Check for open in harness and connector between ECM and starter relay (See
page IN-26).
NG Repair or replace or connector.
OK
Check and replace 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

A15734
- DIAGNOSTICSENGINE
DI-97
1996 TERCEL (RM440U)
ECM Power Source Circuit
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, battery positive voltage is applied to the coil, closing the contacts of
the EFI main relay and supplying power to the terminal +B of the ECM.
WIRING DIAGRAM
DI4LL-02

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).

A15736
DI-100
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
Fuel Pump Control Circuit
CIRCUIT DESCRIPTION
In the diagram below, when the engine is cranked, current flows from terminal ST of the ignition switch to
the starter relay coil and also current flows to terminal STA of ECM (STA signal).
When the STA signal and NE signal are input to the ECM, Tr is turned ON, current flows to coil of the circuit
opening relay, the relay switches on, power is supplied to the fuel pump and the fuel pump operates.
While the NE signal is generated (engine running), the ECM keeps Tr ON (circuit opening relay ON) and the
fuel pump also keeps operating.
DI4LM-02

A15737
DI-102
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
INSPECTION PROCEDURE
TOYOTA hand-held tester:
1 Connect TOYOTA hand-held tester and check operation of fuel pump
(See page MF-1).
OK Check for starter signal circuit.
NG
2 Check for ECM power source circuit (See page DI-97).
NG Repair or replace.
OK
3 Check circuit opening relay (See page MF-40).
NG Replace circuit opening relay.
OK
4 Check voltage between terminal FC of ECM and body ground.
PREPARATION:
(a) Remove the lower finish panel.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal FC of ECM and body
ground.
OK:
Voltage: 9 - 14 V
NG Check for open in harness and connector be-
tween EFI main relay and circuit opening relay,
circuit opening relay and ECM.
OK

A15739
- DIAGNOSTICSENGINE
DI-103
1996 TERCEL (RM440U)
5 Check fuel pump (See page MF-1).
NG Repair or replace fuel pump.
OK
6 Check for open in harness and connector between circuit opening relay and fuel
pump, fuel pump and body ground (See page IN-26).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN-26).
OBD II scan tool (excluding TOYOTA hand-held tester):
1 Check fuel pump operation.
PREPARATION:
(a) Remove the lower finish panel.
(b) Turn the ignition switch ON.
CHECK:
(a) Connect terminal FC of the ECM and the body ground to-
gether.
(b) Check for fuel pressure in the fuel inlet hose when it is
pinched off.
OK:
There is pressure in the inlet hose
HINT:
At this time, you will hear a fuel flowing noise.
OK Check for starter signal circuit.

DI-104
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
NG
2 Check for ECM power source circuit (See page DI-97).
NG Repair or replace.
OK
3 Check circuit opening relay (See page MF-40).
NG Replace circuit opening relay.
OK
4 Check voltage between terminal FC of ECM connector and body ground.
(See page DI-100)
NG Check for open in harness and connector be-
tween EFI main relay and circuit opening relay,
circuit opening relay and ECM.
OK
5 Check fuel pump (See page MF-1).
NG Repair or replace fuel pump.
OK
6 Check for open in harness and connector between circuit opening relay and fuel
pump, fuel pump and body ground (See page IN-26).

DI4LQ-02
- DIAGNOSTICSANTI-LOCK BRAKE SYSTEM
DI-1 15
1996 TERCEL (RM440U)
DIAGNOSTIC TROUBLE CODE CHART
HINT:
Using SST 09843-18020, connect the terminals Tc and E
1, and remove the short pin.
If a malfunction code is displayed during the DTC check, check the circuit listed for that the code. For details
of each code, turn to the page referred to under the ºSee pageº for respective ºDTC No.º in the DTC chart.
DTC No.
(See page)Detection ItemTrouble Area
11
(DI-1 19)Open circuit in ABS control (solenoid) relay circuit

ABS control (solenoid) relay

Open or short in ABS control (solenoid) relay circuit

ECU
12
(DI-1 19)Short circuit in ABS control (solenoid) relay circuit

ABS control (solenoid) relay

B+ short in ABS control (solenoid) relay circuit

ECU
13
(DI-122)Open circuit in ABS control (motor) relay circuit

ABS control (motor) relay

Open or short in ABS control (motor) relay circuit

ECU
14
(DI-122)Short circuit in ABS control (motor) relay circuit

ABS control (motor) relay

B+ short in ABS control (motor) relay circuit

ECU
21
(DI-125)Open or short circuit in solenoid circuit for right front wheel

ABS actuator

Open or short in SFR circuit

ECU
22
(DI-125)Open or short circuit in solenoid circuit for left front wheel

ABS actuator

Open or short in SFL circuit

ECU
23
(DI-125)Open or short circuit in solenoid circuit for right rear wheel

ABS actuator

Open or short in SRR circuit

ECU
24
(DI-125)Open or short circuit in solenoid circuit for left rear wheel

ABS actuator

Open or short in SRL circuit

ECU
31
(DI-128)Right front wheel speed sensor signal malfunction
32
(DI-128)Left front wheel speed sensor signal malfunction
Right front, left front, right rear or left rear speed sensor
O htihd iit33
(DI-128)Right rear wheel speed sensor signal malfunction

Open or short in each speed sensor circuit

ECU
34
(DI-128)Left rear wheel speed sensor signal malfunction
41
(DI-132)Low battery positive voltage or abnormally high battery positive
voltage

Battery

IC regulator

Open or short in power source circuit

ECU
51
(DI-135)Pump motor is locked
Open in pump motor ground
ABS pump motor
Always ONMalfunction in ECU
ECU