Toyota AT180 Series Repair Manual page 73

* EGR CUT CONTROL SYSTEM
THE EGR CUT CONTROL SYSTEM CONTROLS THE VSV (FOR EGR) BY EVALUATING THE SIGNALS FROM EACH SENSOR INPUT TO
THE ECU (INPUT SIGNALS (1, 5, 6, 9)) AND BY SENDING OUTPUT TO TERMINAL EGR OF THE ECU.
* A/C CUT CONTROL SYSTEM
WHEN THE VEHICLE SUDDENLY ACCELERATES FROM LOW ENGINE SPEED, THIS SYSTEM CUTS OFF AIR CONDITIONER
OPERATION FOR A FIXED PERIOD OF TIME IN RESPONSE TO THE VEHICLE SPEED, THROTTLE VALVE OPENING ANGLE AND
INTAKE MANIFOLD PRESSURE IN ORDER TO MAINTAIN ACCELERATION PERFORMANCE.
THE ECU RECEIVES INPUT SIGNALS ((4, 5, 6, 7 AND 10)), AND OUTPUTS SIGNALS TO TERMINAL ACT.
* OVERDRIVE CONTROL SYSTEM
THE ECU CONTROLS THE O/D SOLENOID OF THE AUTOMATIC TRANSAXLE IN RESPONSE TO SIGNALS FROM EACH SENSOR
(INPUT SIGNALS (1, 4, 5, 6 AND 10)) IN ORDER TO MAINTAIN DRIVABILITY AND ACCELERATION PERFORMANCE.
THE ECU OUTPUTS A SIGNAL FROM TERMINAL OD TO CONTROL THE O/D SOLENOID.
3. DIAGNOSIS SYSTEM
WITH THE DIAGNOSIS SYSTEM, WHEN THERE IS A MALFUNCTIONING IN THE ECU SIGNAL SYSTEM, THE MALFUNCTION SYSTEM
IS RECORDED IN THE MEMORY. THE MALFUNCTIONING SYSTEM CAN THEN BE FOUND BY READING THE DISPLAY (CODE) OF
THE CHECK ENGINE WARNING LIGHT.
4. FAIL–SAFE SYSTEM
WHEN A MALFUNCTION OCCURS IN ANY SYSTEM, IF THERE IS A POSSIBILITY OF ENGINE TROUBLE BEING CAUSED BY
CONTINUED CONTROL BASED ON THE SIGNALS FROM THAT SYSTEM, THE FAIL–SAFE SYSTEM EITHER CONTROLS THE SYSTEM
BY USING DATA (STANDARD VALUES) RECORDED IN THE ECU MEMORY OR ELSE STOPS THE ENGINE.
SERVICE HINTS
ENGINE ECU
E 5, E 8
VOLTAGE AT ECU WIRING CONNECTORS
BATT–E1 : ALWAYS 10.0–14.0 VOLTS
+B–E1 : 10.0–14.0 VOLTS (IGNITION SW AT ON POSITION)
+B1–E1 : 10.0–14.0 VOLTS (IGNITION SW AT ON POSITION)
IDL–E1 : 8.0–14.0 VOLTS (IGNITION SW ON AND THROTTLE VALVE OPEN)
PSW–E1 : 4.0–5.0 VOLTS (IGNITION SW ON AND THROTTLE VALVE FULLY CLOSED)
PIM–E2 : 3.3–3.9 VOLTS (IGNITION SW AT ON POSITION)
VCC–E2 : 4.5–5.5 VOLTS (IGNITION SW AT ON POSITION)
#10, #20–E01, E02 : 10.0–14.0 VOLTS (IGNITION SW AT ON POSITION)
THA–E2 : 1.0–3.0 VOLTS (IGNITION SW ON AND INTAKE AIR TEMP. 20°C (68°F))
THW–E2 : 0.1–1.0 VOLTS (IGNITION SW ON AND COOLANT TEMP. 80°C (176°F)
STA–E1 : 6.0–14.0 VOLTS (ENGINE CRANKING)
IGT–E1 : 0.7–1.0 VOLTS (ENGINE CRANKING OR IDLING)
W–E1 : 10.0–14.0 VOLTS (IGNITION SW ON, NO TROUBLE AND ENGINE RUNNING)
A/C–E1 : 8.0–14.0 VOLTS (IGNITION SW ON AND AIR CONDITIONING ON)
ACT–E1 : 4.0–6.0 VOLTS (IGNITION SW ON AND HEATER BLOWER SW ON)
T–E1 : 10.0–14.0 VOLTS (IGNITION SW ON AND CHECK CONNECTOR T–E1 NOT CONNECTED)
: 0.5 OR LESS (IGNITION SW ON AND CHECK CONNECTOR T–E1 CONNECTOR)
NSW–E1 : 0–2.0 VOLTS (IGNITION SW ON AND NEUTRAL START SW POSITION P OR N RANGE)
: 10.0–14.0 VOLTS (IGNITION SW ON AND EX. NEUTRAL START SW POSITION P OR N RANGE)
V–ISC–E1 : 10.0–14.0 VOLTS (ORANKING FOR 10 SECONDS AFTER STARTING)
RESISTANCE AT ECU WIRING CONNECTORS
(DISCONNECT WIRING CONNECTOR)
IDL–E2 : INFINITY (THROTTLE VALVE OPEN)
: 0 Ω (THROTTLE VALVE FULLY OPEN)
PSW–E2
THA–E1 : 2.0 – 3.0 KΩ (INTAKE AIR TEMP. 20°C, 68°F)
THW–E1 : 0.2 – 0.4 KΩ (COOLANT TEMP. 80°C, 176°F)
G1, NE–G–E : 0.17–0.21 KΩ
: 19.–3–22.3 Ω
ISCC–+B
ISCO–+B
0 Ω (THROTTLE VALVE FULLY CLOSED)
INFINITY (THROTTLE VALVE FULLY CLOSED)
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