TERMINALS OF ECU
1. CHECK NO. 1 AIR CONDITIONING AMPLIFIER ASSEMBLY
(a) Disconnect the F42 No. 1 air conditioning amplifier assembly connector.
(b) Measure the voltage and resistance according to the value(s) in the table below.
Terminal No. (Symbol) |
Wiring Color |
Terminal Description |
Condition |
Specified Condition |
---|---|---|---|---|
F42-21 (B) - F42-14 (GND) |
V - W-B |
Battery power source |
Always |
11 to 14 V |
F42-1 (IG+) - F42-14 (GND) |
L - W-B |
Ignition power supply |
Ignition switch ON |
11 to 14 V |
Ignition switch off |
Below 1 V |
|||
F42-14 (GND) - Body ground |
W-B - Body ground |
Ground for main power supply |
Always |
Below 1 Ω |
(c) Reconnect the F42 No. 1 air conditioning amplifier assembly connector.
(d) Measure the voltage according to the value(s) in the table below.
Terminal No. (Symbol) |
Wiring Color |
Terminal Description |
Condition |
Specified Condition |
---|---|---|---|---|
F42-3 (PTC1) - Body ground |
V - Body ground |
PTC NO. 1 relay operation signal |
|
11 to 14 V* |
F42-4 (PTC3) - Body ground |
P - Body ground |
PTC NO. 3 relay operation signal |
|
11 to 14 V* |
F42-5 (TAM) - F42-13 (SG-2) |
V - G |
Cooler thermistor (ambient temperature sensor) signal |
|
1.35 to 1.75 V |
F42-5 (TAM) - F42-13 (SG-2) |
V - G |
Cooler thermistor (ambient temperature sensor) signal |
|
0.9 to 1.2 V |
F42-8 (LOCK) - F42-13 (SG-2) |
R - G |
A/C compressor lock sensor signal |
|
Pulse generation (See waveform 1) |
F42-9 (PRE) - Body Ground |
G - Body Ground |
No. 1 pressure switch signal |
|
Below 1 V |
F42-9 (PRE) - Body Ground |
G - Body Ground |
No. 1 pressure switch signal |
|
4.69 V or higher |
F42-17 (AC1) - F42-14 (GND) |
LG - W-B |
Compressor operation signal |
|
Below 1 V |
F42-18 (MHTR) - F42-14 (GND) |
G - W-B |
MIR HTR relay signal |
|
Below 1 V |
F42-20 (MGC) - F42-14 (GND) |
R - W-B |
Magnet clutch assembly operation signal |
|
Below 1 V |
F42-22 (PTC2) - Body ground |
LG - Body ground |
PTC NO. 2 relay operation signal |
|
11 to 14 V* |
F42-23 (BLW) - F42-14 (GND) |
LG - W-B |
Blower with fan motor sub-assembly control signal |
|
Pulse generation (See waveform 2) |
F42-25 (ALT) - F42-14 (GND) |
L - W-B |
Generator signal (PTC heater control) |
Engine started |
Pulse generation |
F42-27 (ACT) - F42-14 (GND) |
SB - W-B |
Compressor operation signal |
|
4.75 to 5.25 V |
z15-2 (BUS G) - Body ground |
- |
Ground for BUS IC |
Always |
Below 1 V |
z15-3 (BUS) - z15-2 (BUS G) |
- |
BUS IC control signal |
Ignition switch ON |
Pulse generation |
z15-4 (B BUS) - z15-2 (BUS G) |
- |
Power supply for BUS IC |
Always |
11 to 14 V |
z15-6 (TE) - z15-5 (SG-3) |
- |
No. 1 cooler thermistor signal |
|
1.7 to 2.1 V |
|
0.9 to 1.3 V |
HINT:
*: After the measurement conditions are met, wait 30 seconds before performing measurements.
(e) Using an oscilloscope, check waveform 1.
A/C Compressor Lock Sensor Signal
Item |
Content |
---|---|
Terminal No. (Symbol) |
F42-8 (LOCK) - F42-13 (SG-2) |
Tool Setting |
200 mV/DIV., 10 ms./DIV. |
Condition |
|
(f) Using an oscilloscope, check waveform 2.
Blower Motor Control Signal
Item |
Content |
---|---|
Terminal No. (Symbol) |
F42-23 (BLW) - F42-14 (GND) |
Tool Setting |
1 V/DIV., 500 μs/DIV. |
Condition |
|
HINT:
When the blower level is increased, the duty ratio changes accordingly.
2. CHECK HEATER CONTROL ASSEMBLY
(a) Disconnect the F29 heater control assembly connector.
(b) Measure the resistance and voltage according to the value(s) in the table below.
Terminal No. (Symbol) |
Wiring Color |
Terminal Description |
Condition |
Specified Condition |
---|---|---|---|---|
F29-4 (IG+) - F29-11 (GND) |
L - W-B |
IG power supply |
Ignition switch ON |
11 to 14 V |
F29-11 (GND) - Body ground |
W-B - Body ground |
Ground |
Always |
Below 1 Ω |
If the result is not as specified, there may be a malfunction on the wire harness side.
How To Proceed With Troubleshooting
CAUTION / NOTICE / HINT
HINT:
Use the following procedure to troubleshoot the audio and visual system.
*: Use the Techstream.
PROCEDURE
1.
VEHICLE BROUGHT TO WORKSHOP
NEXT
...
Problem Symptoms Table
PROBLEM SYMPTOMS TABLE
HINT:
Use the table below to help determine the cause of problem symptoms.
If multiple suspected areas are listed, the potential causes of the symptoms
are listed in order of probability in the "Suspected Area" ...