Terminals Of Ecu
1. CHECK TIRE PRESSURE WARNING ECU
HINT:
Inspect the connectors from the back side while the connectors are connected.
(a) Disconnect the L14 tire pressure warning antenna and receiver connector.
(b) Measure the voltage according to the value(s) in the table below.
Terminal No. (Symbol) | Wiring Color | Terminal Description | Condition | Specified Condition |
|---|---|---|---|---|
D31-12 (RDA) - D31-9 (GND) |
Y - W-B |
Tire pressure warning antenna and receiver signal |
Ignition switch ON |
11 to 14 V |
(c) Connect the L14 tire pressure warning antenna and receiver connector.
(d) Measure the voltage and resistance according to the value(s) in the table below. If the result is not as specified, the ECU may have a malfunction.
Terminal No. (Symbol) | Wiring Color | Terminal Description | Condition | Specified Condition |
|---|---|---|---|---|
D31-2 (SPD) - D31-9 (GND) |
P - W-B |
Vehicle speed signal |
Vehicle driving |
Pulse generation (see waveform 1) |
D31-3 (TC) - D31-9 (GND) |
BR - W-B |
TC terminal |
Terminal TC not connected |
11 to 14 V |
D31-4 (TACH) - D31-9 (GND) |
V - W-B |
Engine speed signal |
Engine running |
Pulse generation (see waveform 2) |
D31-5 (IND) - D31-9 (GND) |
LG - W-B |
Tire pressure warning light output signal |
|
Below 0.5 V |
After ignition switch is turned to ON, tire pressure warning light illuminates for 3 seconds. |
0.9 to 3.2 V |
|||
D31-6 (RF5V) - D31-9 (GND) |
R - W-B |
Tire pressure warning antenna and receiver power source |
Ignition switch ON |
11 to 14 V |
D31-7 (IG) - D31-9 (GND) |
GR - W-B |
IG power source |
Ignition switch ON |
11 to 14 V |
D31-9 (GND) - Body ground |
W-B - Body ground |
Ground |
Always |
Below 1 Ω |
D31-10 (SIL) - D31-9 (GND) |
P - W-B |
Diagnostic communication |
Ignition switch ON |
8 to 14 V |
D31-11 (GND2) - D31-9 (GND) |
W - W-B |
Tire pressure warning antenna and receiver ground |
Always |
Below 1 Ω |
D31-12 (RDA) - D31-9 (GND) |
Y - W-B |
Tire pressure warning antenna and receiver signal |
Ignition switch ON |
11 to 14 V |
(e) Using an oscilloscope, check waveform 1.
Waveform 1 Item | Content |
|---|---|
Terminal |
D31-2 (SPD) - D31-9 (GND) |
Tool setting |
5 V/DIV, 20 ms./DIV. |
Vehicle condition |
Driving at approximately 20 km/h |
HINT:
The wavelength becomes shorter as the vehicle speed increases.
(f) Using an oscilloscope, check waveform 2.
Waveform 2 Item | Content |
|---|---|
Terminal |
D31-4 (TACH) - D31-9 (GND) |
Tool setting |
5 V/DIV., 10 ms./DIV. |
Vehicle condition |
Idling |
HINT:
The wavelength becomes shorter as the engine speed increases.
Test yourself
A quick Toyota Venza quiz: every answer comes with an explanation and a link to the manual page.