ECM TOYOTA TERCEL 1996 Service User Guide

DI-14
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)DTC No.
(See Page)
Detection ItemTrouble AreaMIL*Memory
P0171
(DI-49)System too Lean
(Fuel Trim)
Air intake (hose loose)
Fuel line pressure
Injector blockage
Oxygen sensor malfunction
Manifold absolute pressure sensor
Engine coolant temp. sensor

P0172
(DI-49)System too Rich
(Fuel Trim)
Fuel line pressure
Injector blockage, leak
Oxygen sensor malfunction
Manifold absolute pressure sensor
Engine coolant temp. sensor

P0300
(DI-52)Random/Multiple Cylinder
Misfire DetectedIgnition system
Injector
FlliP0301
P0302
P0303
P0304
(DI-52)Misfire Detected
- Cylinder 1
- Cylinder 2
- Cylinder 3
- Cylinder 4Fuel line pressure
Compression pressure
Valve clearance not to specification
Valve timing
Manifold absolute pressure sensor
Engine coolant temp. sensor

P0325
(DI-57)Knock Sensor 1 Circuit
MalfunctionOpen or short in knock sensor 1 circuit
Knock sensor 1 (looseness)
ECM

P0335
(DI-60)Crankshaft Position Sensor
Circuit ºAº Malfunction
Open or short in crankshaft position sensor circuit
Crankshaft position sensor
Starter
ECM

P0340
(DI-63)Camshaft Position Sensor
Circuit Malfunction
Open or short in camshaft position sensor circuit
Camshaft position sensor
Starter
ECM

P0420
(DI-73)Catalyst System Efficiency
Below ThresholdThree-way catalytic converter
Open or short in (heated) oxygen sensor circuit
(Heated) oxygen sensor

P0500
(DI-76)Vehicle Speed Sensor
Malfunction
Open or short in vehicle speed sensor circuit
Vehicle speed sensor
Speedometer cable
ECM

P0505
(DI-78)Idle Control System
Malfunction
IAC valve is stuck or closed
Open or short in IAC valve circuit
Open or short in AC1 switch circuit
Air intake (hose loose)

*: 


MIL lights up

- DIAGNOSTICSENGINE
DI-15
1996 TERCEL (RM440U)
Manufacturer Controlled:
DTC No.
(See Page)Detection ItemTrouble AreaMIL*Memory
P1300
(DI-84)Igniter Circuit Malfunction
Open or short in IGF or IGT circuit from igniter to ECM
Igniter
ECM

P1335
(DI-89)Crankshaft Position Sensor
Circuit Malfunction
(during engine running)Open or short in crankshaft position sensor circuit
Crankshaft position sensor
ECM
-
P1600
(DI-92)ECM BATT MalfunctionOpen in back up power source circuit
ECM
P1780
(DI-94)Park/Neutral Position Switch
MalfunctionShort in park/neutral position switch circuit
Park/neutral position switch
ECM

*:-


MIL does not light up



MIL lights up

DI4LH-02
P19551
ECM TerminalsE7 E6
1 2 3 4 5 6 7 8 9 10 11 12 13
23 24 25 26 1920 21 22 18 1415 16 171 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16
- DIAGNOSTICSENGINE
DI-17
1996 TERCEL (RM440U)
TERMINALS OF ECM
Symbols (Terminals No.)Wiring ColorConditionSTD Voltage (V)
BATT (E6-2) - E1 (E7-24)W-R - BRAlways9 - 14
+B (E6-9) - E1 (E7-24)B-R - BRIG switch ON9 - 14
VC (E7-18) - E2 (E7-16)LG-R - BRIG switch ON4.5 - 5.5
VTA (E7 19) E2 (E7 16)YG BR
IG switch ON
Throttle valve fully closed0.3 - 1.0
VTA (E7-19) - E2 (E7-16)Y-G - BRIG switch ON
Throttle valve fully open3.2 - 4.9
PIM (E7 4) E2 (E7 16)PBRIG switch ON3.3 - 3.9PIM (E7-4) - E2 (E7-16)P - BRApply vacuum 26.7 kPa (200 mmHg, 7.9 in.Hg)2.5 - 3.1
THA (E7-15) - E2 (E7-16)L-B - BRIdling, Intake air temp. 20°C (68° F)0.5 - 3.4
THW (E7-3) - E2 (E7-16)G-B - BRIdling, Engine coolant temp. 80°C (176°F) 0.2 - 1.0
STA (E7-11) - E1 (E7-24)B-W - BRCranking6.0 or more
IG switch ON9 - 14
#10 (E7-12) - E01 (E7-13)G - BRIdlingPulse generation
(See page DI-52)
IG switch ON9 - 14
#20 (E7-11) - E01 (E7-13)Y - BRIdlingPulse generation
(See page DI-52)
IG switch ON9 - 14
#30 (E7-25) - E01 (E7-13)R - BRIdlingPulse generation
(See page DI-52)
IG switch ON9 - 14
#40 (E7-24) - E01 (E7-13)L - BRIdlingPulse generation
(See page DI-52)
IGT1 (E7-6) - E1 (E7-24)LG - BRIdlingPulse generation
(See page DI-84)
IGT2 (E7-5) - E1 (E7-24)L-Y - BRIdlingPulse generation
(See page DI-84)
IG switch ON, Disconnect igniter connector4.5 - 5.5
IGF (E7-7) - E1 (E7-24)LG-B - BRIdlingPulse generation
(See page DI-84)
G2(E7-20) - NE- (E7-9)R - WIdlingPulse generation
(See page DI-60)
NE(E7-21) - NE- (E7-9)B - WIdlingPulse generation
(See page DI-60)
FC (E6-4) - E1 (E7-24)G-B - BRIG switch ON9 - 14

DI-18
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)Symbols (Terminals No.)
Wiring ColorConditionSTD Voltage (V)
RSC (E7-1) - E1 (E7-24)L-R - BRIG switch ON
Disconnect ºE7º of ECM connector9 - 14
RSO (E7-14) - E1(E7-24)L - BRIG switch ON
Disconnect ºE7º of ECM connector9 - 14
OX1 (E7-10) - E1 (E7-24)B - BRMaintain engine speed at 2,500 rpm for 2 minutes. after
warming upPulse generation
OX2 (E7-23) - E1 (E7-24)W - BRMaintain engine speed at 2,500 rpm for 2 minutes. after
warming upPulse generation
HT1 (E6 6) E03 (E7 26)WL BRIdlingBelow 3.0HT1 (E6-6) - E03 (E7-26)W-L - BRIG switch ON9 - 14
HT2 (E6 5) E03 (E7 26)WR BRIdlingBelow 3.0HT2 (E6-5) - E03 (E7-26)W-R - BRIG switch ON9 - 14
KNK (E7-8) - E1 (E7-24)B - BRIdlingPulse generation
(See page DI-57)
NSW (E7 2) E1 (E7 24)(M/T)
IG switch ON
Other shift position in ºPº or ºNº position9 - 14
NSW (E7-2) - E1 (E7-24)(M/T)IG switch ON
Shift position in ºPº or ºNº position0 - 3.0
NSW (E7 2) E1 (E7 24)(A/T)
IG switch ON
Other shift position in ºPº or ºNº position9 - 14
NSW (E7-2) - E1 (E7-24)(A/T)IG switch ON
Shift position in ºPº or Nº position0 - 3.0
SPD (E6-13) - E1 (E7-24)Y - BRIG switch ON
Rotate driving wheel slowlyPulse generation
(See page DI-76)
TE1 (E6-8) - E1 (E7-24)G - BRIG switch ON9 - 14
W (E6 10) E1 (E7 24)GR L BRIdling9 - 14W (E6-10) - E1 (E7-24)GR-L - BRIG switch ONBelow 3.0
AC1 (E6 12) E1 (E7 24)LG B BRIdling, A/C switch ONBelow 2.0AC1 (E6-12) - E1 (E7-24)LG-B - BRIdling, A/C switch OFF9 - 14
ACT (E6 14) E1 (E7 24)LBRIdling, A/C switch ON9 - 14ACT (E6-14) - E1 (E7-24)L - BRIdling, A/C switch OFFBelow 2.0
ODSW (E6 3) E1 (E7 24)RW BRIG switch ON, O/D main switch pushed out9 - 14ODSW (E6-3) - E1 (E7-24)R-W - BRIG switch ON, O/D main switch pushed in0 - 3.0
ODT (E6 11) E1 (E7 24)RBRIG switch ON, O/D main switch pushed out9 - 14ODT (E6-11) - E1 (E7-24)R - BRIG switch ON, O/D main switch pushed in0 - 3.0

DI4LI-02
- DIAGNOSTICSENGINE
DI-19
1996 TERCEL (RM440U)
PROBLEM SYMPTOMS TABLE
SymptomSuspect AreaSee page
Does not start (Engine does not crank)1. Starter and starter relayST-13
ST-31
Does not start (No combustion)1. ECM power source circuit
2. Fuel pump control circuitDI-97
DI-100
Does not start (No complete combustion)1. Fuel pump control circuitDI-100
Difficult to start (Engine cranks normally)
1. Starter signal circuit
2. Fuel pump control circuit
3. CompressionDI-90
DI-100
EM-3
Difficult to start (Cold engine)1. Starter signal circuit
2. Fuel pump control circuitDI-90
DI-100
Difficult to start (Hot engine)1. Starter signal circuit
2. Fuel pump control circuitDI-90
DI-100
Poor idling (High engine idle speed)1. A/C signal circuit
2. ECM power source circuitAC-66
DI-97
Poor idling (Low engine idle speed)1. A/C signal circuit
2. Fuel pump control circuitAC-66
DI-100
Poor idling (Rough idling)1. Compression
2. Fuel pump control circuitEM-3
DI-100
Poor idling (Hunting)1. ECM power source circuit
2. Fuel pump control circuitDI-97
DI-100
Poor driveability (Hesitation/Poor acceleration)
1. Fuel pump control circuit
2. A/T faulty (A132L)
A/T faulty (A242L)
3. A/C cut control circuitDI-100
AX-10
AX-13
DI-106
Poor driveability (Surging)1. Fuel pump control circuitDI-100
Engine stall (Soon after starting)1. Fuel pump control circuitDI-100
Engine stall (During A/C operation)1. A/C signal circuit
2. Engine control module (ECM)AC-66
IN-26

DI1E3-06
P01242
750
450
100 (3.96)
3.6
1.2
(840) 2.4
150
60 20
(112)kPa mmHg
Manifold Absolute Pressure
Output Voltage
V DI-20
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
CIRCUIT INSPECTION
DTC P0105 Manifold Absolute Pressure/Barometric
Pressure Circuit Malfunction
CIRCUIT DESCRIPTION
By a built-in sensor unit, the manifold absolute pressure sensor
detects the intake manifold pressure as a voltage. The ECM
then determines the basic injection duration and basic injection
advance angle based on this voltage. Since the manifold abso-
lute pressure sensor does not use the atmospheric pressure as
a criterion, but senses the absolute pressure inside the intake
manifold (the pressure in proportion to the present absolute
vacuum 0), it is not influenced by fluctuations in the atmospheric
pressure due to high altitude and other factors. This permits it
to control the air-fuel ratio at the proper lever under all condi-
tions.
DTC No.DTC Detection ConditionTrouble Area
P0105Open or short manifold absolute pressure sensor circuit

Open or short in manifold absolute pressure sensor circuit

Manifold absolute pressure sensor

ECM
If the ECM detects DTC P0105, it operates the fail-safe function, keeping the ignition timing and injection
volume constant and making it possible to drive the vehicle.
HINT:
After confirming DTC P0105, use the OBDII scan tool or TOYOTA hand-held tester to confirm the manifold
absolute pressure from the CURRENT DATA.
Manifold absolute pressureTrouble Area
0 kPaPIM circuit short
130 kPa or more
VC circuit open or short
PIM circuit open
E2 circuit open

A15678
A15679
DI-22
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
2 Check voltage between terminals VC and E2 of ECM connector.
PREPARATION:
(a) Remove the lower finish panel.
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals VC and E2 of the ECM
connector.
OK:
Voltage: 4.5 - 5.5 V
NG Check and replace ECM (See page IN-26).
OK
3 Check voltage between terminals PIM and E2 of ECM connector.
PREPARATION:
(a) Remove the lower finish panel.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals PIM and E2 of ECM con-
nector.
OK:
Voltage: 3.3 - 3.9 V
OK Check and replace ECM (See page IN-26).
NG
4 Check for open and short in harness and connector between manifold absolute
pressure sensor and ECM.
NG Repair or replace harness or connector.
OK
Replace manifold absolute pressure sensor.

FI4741 (-4) 0.1 0.2
0 -20 0.3 0.51 2 35 10 20 30
20 40 60 80 100
(32) (68) (104) (140) (212)(176)
Resistance kW
Acceptable
Temp.°C (°F) (fig.1)
DI-24
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
DTC P0110 Intake Air Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
The intake air temperature sensor is built into the air cleaner
cap and senses the intake air temperature. A thermistor built in
the sensor changes the resistance value according to the in-
take air temperature. The lower the intake air temperature, the
greater the thermistor resistance value, and the higher the in-
take air temperature, the lower the thermistor resistance value
(See Fig. 1). The intake air temperature sensor is connected to
the ECM (See next page). The 5 V power source voltage in the
ECM is applied to the intake air temperature sensor from the ter-
minal THA via a resistor R. That is, the resistor R and the intake
air temp. sensor are connected in series. When the resistance
value of the intake air temperature sensor changes in accor-
dance with changes in the intake air temperature, the potential
at terminal THA also changes. Based on this signal, the ECM
increases the fuel injection volume to improve driveability dur-
ing cold engine operation.
If the ECM detects the DTC ºP0110º, it operates the fail-safe
function in which the intake air temperature is assumed to be
20° (68°F).
Reference
Intake air temp.
°C (°F)Resistance
(kW)Voltage
(V)
-20 (-4)16.24.3
0 (32)5.93.4
20 (68)2.52.4
40 (104)1.11.5
60 (140)0.60.9
80 (176)0.30.5
100 (212)0.20.3
DTC No.DTC Detecting ConditionTrouble Area
P0110Open or short in intake air temp. sensor circuit

Open or short in intake air temp. sensor circuit

Intake air temp. sensor

ECM
HINT:
After confirming DTC P0110, use the OBD II scan tool or TOYOTA hand-held tester to confirm the intake
air temperature from the CURRENT DATA.
Temperature DisplayedMalfunction
-40°C (-40°F)Open circuit
140°C (284°F) or moreShort circuit
DI1E5-08

A10940
ECM
E7
E7 L-B
BR5V
R
E1 E2 THA
2
1 Intake Air Temp. Sensor
15
16
- DIAGNOSTICSENGINE
DI-25
1996 TERCEL (RM440U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
If DTC P0105, P0106, P0110, P0115, P0120 are output simultaneously, E2 (sensor ground) may be open.
1 Connect OBD II scan tool or TOYOTA hand-held tester, and read value of intake
air temperature.
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) Turn the ignition switch ON and OBD II scan tool or TOYOTA hand-held tester main switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYOTA hand-held tester.
OK:
Same value as the actual intake air temperature.
HINT:

If there is open circuit, OBD II scan tool or TOYOTA hand-held tester indicates -40°C (-40°F).

If there is short circuit, OBD II scan tool or TOYOTA hand-held tester indicates 140°C (284°F) or more.
NG -40°C (-40°F) ... Go to step 2.
140°C (284°F) or more ... Go to step 4.
OK
Check for intermittent problems
(See page DI-3).

A15681
A15682
DI-26
- DIAGNOSTICSENGINE
1996 TERCEL (RM440U)
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the intake air temp. sensor connector.
(b) Connect sensor wire harness terminals together.
(c) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand-held tester.
OK:
Temperature value: 140°C (284°F) or more
OK Confirm good connection at sensor.
If OK, replace intake air temp. sensor.
NG
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove the lower finish panel.
(b) Connect terminals THA and E2 of ECM connector togeth-
er.
HINT:
Intake air temperature sensor connector is disconnected. Be-
fore checking, do a visual and contact pressure check for the
ECM connector (See page IN-26).
(c) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand-held tester.
OK:
Temperature value: 140°C (284°F) or more
OK Open in harness between terminal E2 or termi-
nal THA, repair or replace harness.
NG
Confirm good connection at ECM.
If OK, replace ECM.