1996 TOYOTA TERCEL check engine

DI-72
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
4 Check operation of the for EGR (See page EC-7).
NG Replace VSV for EGR.
OK
Check for open and short in harness and con-
nector between engine room R/B and ECM
(See page IN-26).
5 Check EGR vacuum modulator (See page EC-7).
NG Repair or replace.
OK
6 Check manifold absolute pressure sensor (See page DI-23).
NG Repair or replace.
OK
Check and replace ECM (See page IN-26).

FI7132
Engine Speed
2,500 - 3,000 rpm
Idling
IG SW OFF
Warmed up3 min. or soCheckTime (a)(c)
(d)
(b)
FI6514
OX Signal Waveform (Oscilloscope)
1.0 V
0 V
200 m sec. /Division
DI-74
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
CONFIRMATION ENGINE RACING PATTERN
(a) Connect the TOYOTA hand-held tester to the DLC3, or connect the probe of the oscilloscope between
terminals OX1, OX2 and E1 of ECM.
(b) Start engine and warm it up with all accessories switched OFF until engine coolant temperature is
stable.
(c) Race the engine at 2,500 - 3,000 rpm for about 3 minutes.
(d) After confirming that the waveform of the oxygen sensor, bank 1 sensor 1 (OX1), oscillate around 0.5
V during feedback to the ECM, check the waveform of the heated oxygen sensor, bank 1 sensor 2
(OX2).
HINT:
If there is a malfunction in the system, the waveform of the
heated oxygen sensor, bank 1 sensor 2 (OX2), is almost the
same as that of the oxygen sensor, bank 1 sensor 1 (OX1), on
the left.
There are some cases where, even though a malfunction ex-
ists, the MIL may either light up or not light up.
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0420) being output?
YES Go to relevant DTC chart.
NO
2 Check heated oxygen sensor (bank 1 sensor 2) (See page DI-44).

A15713
AT7809
4.5 - 5.5 V
0
Turn the wheel
- DIAGNOSTICSENGINE
DI-77
1996 TERCEL (RM440U)
INSPECTION PROCEDURE
1 Check operation of speedometer.
CHECK:
Drive the vehicle and check if the operation of the speedometer in the combination meter is normal.
HINT:
The vehicle speed sensor is operating normally if the speedometer display is normal.
NG Check speedometer circuit. See combination
meter troubleshooting.
OK
2 Check voltage between terminal SPD of ECM connector and body ground.
PREPARATION:
(a) Remove the lower finish panel.
(b) Shift the shift lever to neutral.
(c) Jack up one of the front wheels.
(d) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal SPD of the ECM con-
nector and the body ground when the wheel is turned slowly.
OK:
Voltage is generated intermittently.
NG Check and repair harness and connector be-
tween combination meter and ECM.
OK
Check and replace ECM (See page IN-26).

A15716
- DIAGNOSTICSENGINE
DI-79
1996 TERCEL (RM440U)
INSPECTION PROCEDURE
1 Check air induction system (See page MF-1).
NG Repair or replace.
OK
2 Check A/C signal circuit (See page AC-66).
NG Repair or replace.
OK
3 Check voltage between terminals RSO, RSC of ECM connector and body ground.
PREPARATION:
(a) Remove the lower finish panel.
(b) Disconnect the E7connector of ECM.
(c) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal RSO and RSC of the
ECM connector and the body ground.
OK:
Voltage: 9 - 14 V
OK Go to step 5.
NG
4 Check IAC valve (See page MF-33).
NG Replace IAC valve.
OK

DI-80
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
Check for open and short in harness and connector between junction connector and IAC valve,
IAC valve and ECM (See page IN-26).
5 Check operation of IAC valve (See page MF-36).
NG Repair or replace IAC valve.
OK
Check and replace ECM (See page IN-26).

A15717
- DIAGNOSTICSENGINE
DI-81
1996 TERCEL (RM440U)
DTC P0510 Closed Throttle Position Switch Malfunction
CIRCUIT DESCRIPTION
Refer to DTC P0120 on page DI-33.
DTC No.DTC Detection ConditionTrouble Area
P0510Closed throttle position switch does not turn ON even once
when vehicle is driven (2 trip detection logic)
Open in closed throttle position switch circuit

Closed throttle position switch

ECM
HINT:
After confirming DTC P0510, use the TOYOTA hand-held tester to confirm the closed throttle position switch
signal from the CURRENT DATA.
Throttle ValveClosed Throttle Position Switch SignalMalfunction
Fully closedOFFOpen circuit
Fully openONShort circuit
WIRING DIAGRAM
Refer to DTC P0120 on page DI-33.
INSPECTION PROCEDURE
HINT:
If DTCs P0110, P0115 and P0120 are output simultaneously, E2 (sensor ground) may be open.
TOYOTA hand-held tester:
1 Check for open in harness or ECM.
PREPARATION:
(a) Connect the TOYOTA hand-held tester to the DLC3.
(b) Disconnect the throttle position sensor connector.
(c) Connect the sensor wire harness terminals between ter-
minals 3 and 4.
(d) Turn the ignition switch ON.
CHECK:
Read thg CTP switch signal on the TOYOTA hand-held tester.
OK:
CTP switch signal: ON
OK Confirm good connection at sensor. If OK, re-
place throttle position sensor.
NG
DI95R-01

A15718
A15719
DI-82
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
2 Check for open in harness or ECM.
PREPARATION:
(a) Remove the glove compartment (See page MF-54).
(b) Connect terminals IDL and E2 of the ECM connector to-
gether.
HINT:
The throttle position sensor connector is disconnected. Before
checking, do a visual check and contact pressure check for the
connector (See page IN-26).
(c) Turn the ignition switch ON.
CHECK:
Read the CTP switch signal on the TOYOTA hand-held tester.
OK:
CTP switch signal: ON
OK Open in harness between ECM and throttle
position sensor, repair or replace harness.
NG
Confirm connection at ECM. If OK, replace
ECM.
OBD II scan tool (excluding TOYOTA hand-held tester):
1 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the throttle position sensor connector.
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals 3 and 4 of the throttle
position sensor connector.
OK:
Voltage: 9 - 14 V
OK Confirm good connection at sensor. If OK, re-
place throttle position sensor.

- DIAGNOSTICSENGINE
DI-83
1996 TERCEL (RM440U)
NG
2 Check for open in harness and connector between throttle position sensor and
ECM (See page IN-26).
NG Open in harness between ECM and throttle
position sensor.
OK
Confirm connection at ECM. If OK, replace
ECM.