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:
Inspection
1. INSPECT STEERING PAD SWITCH LH (w/o
Navigation System)
Measure the resistance according to the values in
the table below.
Standard resistan
If the result is not as specified, replace the steering
pad switch LH.
2. INSPECT STEERING PAD SWITCH RH (w/ Navigation
System)
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Oxygen (A/F) Sensor Pumping Current Circuit
DTC P2238 Oxygen (A/F) Sensor Pumping Current Circuit
Low (Bank 1 Sensor 1)
DTC P2239 Oxygen (A/F) Sensor Pumping Current Circuit
High (Bank 1 Sensor 1)
DTC P2241 Oxygen (A/F) Sensor Pumping Current Circuit
Low (Bank 2 Sensor 1)
DTC P2242 Oxygen (A/F) Sensor Pumping Current Circuit
High (Bank ...
Disassembly
1. REMOVE COOLER DRYER
(a) Using a hexagon wrench 14 mm (0.55 in.), remove
the cap from the modulator.
(b) Remove the O-ring from the cap.
(c) Using needle nose pliers, remove the cooler dryer. ...
