DTC C2154/54: Initiator Driver Circuit (Open) [08/2013 - ]: Procedure

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

CHECK HARNESS AND CONNECTOR (TIRE PRESSURE MONITOR INITIATOR DRIVER IG VOLTAGE)

Turn the power switch off.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Disconnect the H79 tire pressure monitor initiator driver connector.

Measure the voltage and resistance according to the value(s) in the table below.

Standard Voltage

Tester Connection	Condition	Specified Condition
H79-8 (IG) - Body ground	Power switch on (IG)	10 to 16 V

Standard Resistance

Tester Connection	Condition	Specified Condition
H79-5 (GND) - Body ground	Always	Below 1 Ω

TEXT IN ILLUSTRATION

*a	Front view of wire harness connector (to Tire Pressure Monitor Initiator Driver)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step

CHECK HARNESS AND CONNECTOR (TIRE PRESSURE MONITOR INITIATOR DRIVER - TIRE PRESSURE WARNING ECU AND RECEIVER)

Turn the power switch off.
Disconnect the H79 tire pressure monitor initiator driver connector.
Disconnect the P29 or P25 tire pressure warning ECU and receiver connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

FOR FMVSS138 TYPE

Tester Connection	Condition	Specified Condition
H79-6 (SIL) - P29-8 (ALSI)	Always	Below 1 Ω
H79-6 (SIL) - Body ground	Always	10 kΩ or higher

FOR ECE-R64 TYPE

Tester Connection	Condition	Specified Condition
H79-6 (SIL) - P25-8 (ALSI)	Always	Below 1 Ω
H79-6 (SIL) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step

CHECK WAVEFORM

Connect the H79 tire pressure monitor initiator driver connector.

Using an oscilloscope, check the waveform.

Waveform

Item	Contents
Terminal	H79-6 (SIL) - H79-5 (GND)
Tool setting	5 V/DIV, 5 ms./DIV.
Vehicle condition	Power switch on (IG)

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 tire pressure warning ECU and receiver can be considered to be normal.

Voltage alternates between high and low voltage.

TEXT IN ILLUSTRATION

*a	Component with harness connected (Tire Pressure Monitor Initiator Driver)
*b	Example
*c	GND

NG → See step 5

OK → See step 4

REPLACE TIRE PRESSURE MONITOR INITIATOR DRIVER. Refer to REMOVAL [08/2013 - ]
REPLACE TIRE PRESSURE WARNING ECU AND RECEIVER. Refer to REMOVAL [08/2013 - ]