On-Vehicle Inspection [10/2014 - 10/2015]: Procedure

INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (SIGNAL READING CHECK)

NOTE:

Both present and history signal readings will be cleared if the engine room junction block assembly is removed. Make sure not to remove it before inspection.

HINT:

The signal readings of the engine room junction block assembly can be checked by inspecting the voltage at the diagnosis terminal.

Signal reading check

Turn the engine switch on (IG).

Connect the positive (+) terminal of a voltmeter to the engine room junction block assembly and the negative (-) terminal to the body ground.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

TEXT IN ILLUSTRATION

*a	Component with harness connected (Engine Room Junction Block Assembly)
*b	Diagnosis Terminal

Using the illustration below as a reference, determine whether any channels are malfunctioning based on the observed signal reading.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

Present signal reading and history signal reading will be displayed alternately after the engine switch is turned on (IG). By measuring the duration of each header, the present signal reading and history signal reading can be recognized.
A unit malfunction indicates an internal malfunction of the engine room junction block assembly. If a malfunction is detected for any channel from channel 0 to 9, an electrical load connected to the engine room junction block assembly may be malfunctioning or there may be a short in the engine room junction block assembly circuit or in the wire harness.
The present signal reading will be stored as a history signal reading when electrical loads are operated after a malfunctioning part returns to normal.
Both present and history signal readings can be cleared by disconnecting the cable from the negative (-) battery terminal.

Depending on the specification, different electrical loads connected to channels 0 to 9 are provided. Refer to the table below:

Channel	Connected Electrical Load
Channel	w/o Front Fog Light and w/ Halogen Headlight	w/ Front Fog Light and w/ Halogen Headlight	w/ HID Headlight
ch0	Magnetic clutch
ch1	-
ch2	Stop lights
ch3	-
ch4	-		LED daytime running lights
ch5	-	Front fog lights
ch6	Rear window defogger wire
ch7	Mirror heater
ch8	High beam headlight LH
ch9	High beam headlight RH

INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (RESULTS OF SIGNAL READING CHECK)

Results of signal reading check

Depending on the signal reading, perform troubleshooting according the table below.

Output Signal Reading	Repair Method
Normal	Continue troubleshooting for each system.
The unit is malfunctioning.	Replace the engine room junction block.
A malfunction in a channel (ch0 to ch9)	Check for a short in the wire harnesses between the engine room junction block assembly and each electrical load. Inspect each of the electrical loads. Replace the engine room junction block.

HINT:

Make sure to clear the signal readings by disconnecting the cable from the negative (-) battery terminal after replacement or repair of the malfunctioning part.

If no signal readings are output, perform troubleshooting according to the following troubleshooting procedure.

Remove the engine room junction block assembly (Refer to REMOVAL [10/2014 - ] ).

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

Standard Voltage

Tester Connection	Condition	Specified Condition
1F-15 (IGN) - Body ground	Engine switch on (IG)	11 to 14 V

TEXT IN ILLUSTRATION

*a	Component without engine room junction block assembly (Engine Room Relay Block and Junction Block Assembly)

If the result is not as specified, repair or replace the wire harness or connector.