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:
Removal
HINT:
Use the same procedures for the RH side and LH side.
The procedures listed below are for the LH side.
1. PRECAUTION
CAUTION: Be sure to read "PRECAUTION" thoroughly before
servicing.
2. DISCONNECT CABLE FROM NEGATIVE BATTERY
TERMINAL
NOTICE:
Wait for 90 seconds ...
Replacement
1. REPLACE GENERATOR DRIVE END FRAME BEARING
(a) Remove the 4 screws and retainer plate from the
drive end frame.
(b) Using SST and a hammer, tap out the drive end
frame bearing from the drive end frame.
SST 09950-60010 (09951-00250), 09950-70010
(09951-07100)
(c) Using SST and a ...
Engine Coolant Temperature Receiver Gauge Malfunction
DESCRIPTION
The meter CPU receives engine coolant temperature signals from the ECM via
the multiplex
communication lines. The meter CPU displays engine coolant temperature that is
calculated based on the
data received from the ECM.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
If there is ...