Toyota Tacoma 2015-2018 Service Manual: Terminals Of Ecu

Toyota Tacoma 2015-2018 Service Manual / Tire And Wheel / Tire Pressure Warning System / Terminals Of Ecu

TERMINALS OF ECU

1. CHECK TIRE PRESSURE WARNING ECU AND RECEIVER

(a) Disconnect the T14 tire pressure warning ECU and receiver connector and measure the voltage and resistance on the wire harness side.

Text in Illustration

*A	w/o Wireless Door Lock System
*B	w/o Smart Key System with Wireless Door Lock System
*C	w/ Smart Key System
*a	Front view of wire harness connector (to Tire Pressure Warning ECU and Receiver)

w/o Wireless Door Lock System

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
T14-1 (IG) - T14-12 (GND)	LG - W-B	IG power source	Ignition switch ON	10 to 16 V
T14-12 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω

w/o Smart Key System with Wireless Door Lock System

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
T25-1 (IG) - T25-12 (GND)	LG - W-B	IG power source	Ignition switch ON	10 to 16 V
T25-7 (+B) - T25-12 (GND	BE - W-B	Power supply (from battery)	Always	10 to 16 V
T25-12 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω

w/ Smart Key System

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
T24-1 (IG) - T24-12 (GND)	LG - W-B	IG power source	Ignition switch ON	10 to 16 V
T24-7 (+B) - T24-12 (GND)	BE - W-B	Power supply (from battery)	Always	10 to 16 V
T24-12 (GND) - Body ground*1	W-B - Body ground	Ground	Always	Below 1 Ω

(b) Connect the T14*1, T25*2, T24*3 tire pressure warning ECU and receiver connector.

(c) Measure the voltage and resistance according to the value(s) in the table below. If the result is not as specified, the ECU may be malfunctioning.

HINT:

Measure the values on the wire harness side while the connector is connected.

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
T14-3 (CLSW) - T14-12 (GND)1 T25-3 (CLSW) - T25-12 (GND)2 T24-3 (CLSW) - T24-12 (GND)*3	R - W-B	Tire pressure warning reset switch	Ignition switch ON Tire pressure warning reset switch on	Below 1.5 V
	R - W-B	Tire pressure warning reset switch	Ignition switch ON Tire pressure warning reset switch off	8 to 15 V
T14-4 (RDA) - T14-12 (GND)1 T25-4 (RDA) - T25-12 (GND)2 T24-4 (RDA) - T24-12 (GND)*3	B - W-B	Output signals	Ignition switch ON	Pulse generation (see waveform 1)
T14-5 (PRG) - T14-12 (GND)1 T25-5 (PRG) - T25-12 (GND)2 T24-5 (PRG) - T24-12 (GND)*3	GR - W-B	Input signals	Ignition switch ON	Pulse generation (see waveform 1)

*1: w/o Wireless Door Lock System
*2: w/o Smart Key System with Wireless Door Lock System
*3: w/ Smart Key System

(d) Using an oscilloscope, check waveform 1.

Waveform 1:

Item	Contents
Terminal	T14-4 (RDA) - T14-12 (GND)1 T25-4 (RDA) - T25-12 (GND)2 T24-4 (RDA) - T24-12 (GND)3 T14-5 (PRG) - T14-12 (GND)1 T25-5 (PRG) - T25-12 (GND)2 T24-5 (PRG) - T24-12 (GND)3
Tool setting	5 V/DIV., 5 ms./DIV.
Vehicle condition	Ignition switch ON

Item

Contents

Terminal

T14-4 (RDA) - T14-12 (GND)*1

T25-4 (RDA) - T25-12 (GND)*2

T24-4 (RDA) - T24-12 (GND)*3

T14-5 (PRG) - T14-12 (GND)*1

T25-5 (PRG) - T25-12 (GND)*2

T24-5 (PRG) - T24-12 (GND)*3

Tool setting

5 V/DIV., 5 ms./DIV.

Vehicle condition

Ignition switch ON

*1: w/o Wireless Door Lock System
*2: w/o Smart Key System with Wireless Door Lock System
*3: w/ Smart Key System

Text in Illustration

*a	Example
*b	GND

HINT:

The waveform shown in the illustration is an example. If the tester displays a waveform that alternates between high and low, where high is a voltage that is between the IG power source voltage and a voltage 2.2 V lower than the IG power source voltage, and where low is a voltage of between 0 and 1.2 V, the ECU can be judged normal.

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