1996 TOYOTA TERCEL ignition

A15728
A15729
DI-92
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
DTC P1600 ECM BATT Malfunction
CIRCUIT DESCRIPTION
Battery positive voltage is supplied to terminal BATT of the ECM even when the ignition switch is OFF for
use by the DTC memory and air-fuel ratio adaptive control value memory, etc.
DTC No.DTC Detection ConditionTrouble Area
P1600Open in back up power source circuit
Open in back up power source circuit

ECM
HINT:
If DTC P1600 appear, the ECM does not store another DTC.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check voltage between terminal BATT of ECM connector and body ground.
PREPARATION:
Remove the lower finish panel.
CHECK:
Measure the voltage between terminal BATT of the ECM con-
nector and the body ground.
OK:
Voltage: 9 - 14 V
OK Check and replace ECM (See page IN-26).
NG
DI01I-24

A15733
DI-96
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
NG Replace park/neutral position switch.
OK
2 Check voltage between terminal NSW of ECM connector and body ground.
PREPARATION:
(a) Remove the lower finish panel.
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal NSW of the ECM con-
nector and the body ground after the shift lever is moved to the
following positions.
Shift lever positionP or NL, 2, D or R
Voltage0 - 3 V9 - 14 V
OK Check and replace ECM (See page IN-26).
NG
Check for open and short in harness and con-
nector between ECM and park/neutral posi-
tion switch (See page IN-26).

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.