Toyota Sienna Service Manual: Check and replace ecu
• When no measuring condition is specified, perform the inspection with the engine stopped and the ignition switch on.
• Check that the connectors are fully seated. Check for loose, corroded or broken wires.
(a) First, check the ECU ground circuit. If it is faulty, repair it. If it is normal, the ECU could be faulty.
Temporarily replace the ECU with a normally functioning one and check if the symptoms occur. If the trouble symptoms disappear, replace the original ECU.
(1) Measure the resistance between the ECU ground terminal and body ground.
Standard resistance: Below 1 Ω
(2) Disconnect the ECU connector. Check the ground terminal on the ECU side and wire harness side for bending, corrosion or foreign matter. Lastly, check the contact pressure of the female terminals.
Check for short circuit
(a) If the wire harness is ground shorted (Fig. 5), locate the section by
conducting a resistance check with the body ground (below).
(b) Check the resistance with the body ground.
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Other materials:
If your vehicle needs to
be towed
If towing is necessary, we recommend having your vehicle
towed by your Toyota dealer or commercial towing service,
using a wheel-lift type truck or flat bed truck.
Use a safety chain system for all towing, and abide by all state/
provincial and local laws.
2WD models: If towing your vehicle ...
Terminals of ECU
1. INSTRUMENT PANEL JUNCTION BLOCK
(MULTIPLEX NETWORK BODY ECU)
Disconnect the B6, B7 and B9 ECU connectors.
Disconnect the 1A, 1C, 1K, 1L and 1P J/B
connectors.
Check the voltage or resistance according to the
value(s) in the table below (wire harness side
connector).
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Wrong Disc/ Disc cannot be Read
DTC 44-41 Wrong Disc
DTC 44-42 Disc cannot be Read
DESCRIPTION
DTC No.
DTC Detection Condition
Trouble Area
44-41
An unsuitable disc is inserted
DVD
Television display assembly
44-42
The disc cannot be read.
INSPECTION ...