CHECK AT ECU TERMINAL
SIMPLIFIED WIRING SYSTEM (SWS)54B-484
FRONT-ECU
NOTE: Terminal voltages cannot be measured as the
front-ECU is installed directly on the relay box.
Therefore, this information is only for reference.
TERMINAL
NO.INSPECTION ITEM INSPECTION CONDITION NORMAL VALUE
1 Output to fog lamp relay When the fog lamps are on Battery positive voltage
2 Output to headlamp (high-beam) When headlights (high-beam)
are onBattery positive voltage
3, 4 Battery power supply (for
headlamp)Always Battery positive voltage
5 Battery power supply (for
taillamp)Always Battery positive voltage
6 Output to headlamp (low-beam) When headlights (low-beam) are
onBattery positive voltage
7 Battery power supply (for ECU) Always Battery positive voltage
8 Output to taillamps When taillamps are on Battery positive voltage
9
11
21 Output to windshield washer When windshield washer is on Battery positive voltage
22 SWS communication line Always 0
12 V (pulse signal)
23 Input of automatic stop signal to
windshield wiperWhen windshield wiper is on Battery positive voltage
24 Power supply to ignition switch
(ACC)Ignition switch: "ACC" Battery positive voltage
25 Input of backup signal from
headlamp switchHeadlamp switch: ON0 V
26 Input of backup signal to
windshield wiperWindshield low-speed wiper
switch or windshield high-speed
wiper switch: ON0 V
27 Output to windshield wiper
(low-speed)When windshield wiper is on (at
low speed)Battery positive voltage
28 Output to windshield wiper
(high-speed)When windshield wiper is on (at
high speed)Battery positive voltage
30 Power supply to ignition switch
(IG2)Ignition switch: "ON" Battery positive voltage
31 Ground Always 0 V
CENTRALISED JUNCTION
CIRCUIT DIAGRAMS90-13
19 Front-ECU (Field
effect transistor for
headlamp: Low)Fuse 10 Red Headlamp (LH) and headlamp (Low:
LH)
20 Front-ECU (Taillamp
relay)7.5 Brown A/C-ECU, A/T selector lever position
illumination lamp, combination meter,
fog lamp switch, headlamp (RH),
glove box lamp, hazard warning lamp
switch, multi-center display unit,
radio, CD player, rear combination
lamp (RH), rheostat and TCL switch
21 7.5 Brown Headlamp (LH), license plate lamp
and rear combination lamp (LH)
22 Battery/Alternator
(Fusible link No.27)15 Blue A/C-ECU, column switch,
combination meter, ETACS-ECU,
front-ECU, key reminder switch, multi-
center display unit, radio, CD player,
and vanity mirror lamp
23 Ignition switch (ACC) 10 Red A/C-ECU, accessory socket relay,
ETACS-ECU, multi-center display
unit, radio, CD player.
24 Battery/Alternator
(Fusible link No.27)15 Blue Fuel pump module
25 Ignition switch (ACC) 30 Green Front-ECU and windshield wiper
motor
26 Battery/Alternator
(Fusible link No.27)Fusible
link20 Light blue Anti-lock braking system(solenoid
valve)
27
Alternator120
Battery, front-ECU, fusible link Nos.1,
2, 3, 4, 5 and 26 and fuse Nos.6, 7, 8,
9, 10, 11, 13, 14, 15, 22 and 24 (in
relay box) NO. POWER SUPPLY
CIRCUITNAME RATED
CAPACITY (A)HOUSING
COLOURLOAD CIRCUIT
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-79
STEP 8. Measure the voltage at A/C compressor assembly
connector B-28.
(1) Disconnect A/C compressor assembly connector B-28 and
measure the voltage at the relay box side.
(2) Disconnect powertrain control module connector B-20 and
ground harness side terminal No.6.
(3) Turn the ignition switch to the "ON" position.
(4) A/C compressor assembly connector B-28 terminal 1 and
ground.
The measured value should be approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approx. 12 volts?
YES : Go to Step 15.
NO : Go to Step 9.
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-80
STEP 9. Measure the voltage at A/C compressor clutch
relay connector B-18X.
The top and bottom of the A/C compressor connector are
difficult to identify. Prior to inspection, confirm the triangle
mark on the relay box.
(1) Disconnect A/C compressor connector B-18X and measure
the voltage at the relay box side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 2 and ground.
The measured value should be approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approx. 12 volts?
YES : Go to Step 11.
NO : Go to Step 10.
STEP 10. Check the wiring harness between A/C
compressor clutch relay connector B-18X (terminal 2) and
the ignition switch (IG2).
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-82
STEP 11. Measure the voltage at A/C compressor clutch
relay connector B-18X.
The top and bottom of the A/C compressor connector are
difficult to identify. Prior to inspection, confirm the triangle
mark on the relay box.
(1) Disconnect A/C compressor connector B-18X and measure
the voltage at the wiring harness side.
(2) Measure the voltage between terminal 1 and ground.
The measured value should be approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approx. 12 volts?
YES : Go to Step 13.
NO : Go to Step 12.
STEP 12. Check the wiring harness between A/C
compressor clutch relay connector B-18X (terminal 1) and
the battery.
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-85
STEP 16. Measure the voltage at A/C-ECU connector C-15.
(1) Disconnect A/C-ECU connector C-15 and measure the
voltage at the relay box side.
(2) Disconnect powertrain control module connector B-20 and
ground harness side terminal No.6.
(3) Turn the ignition switch to the "ON" position.
(4) Measure the voltage between A/C-ECU connector C-15
terminal No.10 and ground.
The measured value should be approximately 12 volts
(battery positive voltage).
Q: Does the measured voltage correspond with this range?
YES : Go to Step 18.
NO : Go to Step 17.
