2006 Lexus ES 3.3L no start no communication
This is my daughter's car and my first adventure
with Lexus. Having read all your ATS techniques I thought I would try fixing this beast on this weekend. Problem is
no start and I don't see the check engine light on. What puzzled me is the I have checked the power and ground
supply to the ecm including the dlc pin terminals and all bus communication voltages are within specification. I
know I have no security problem issues because the light goes on and off as it is supposed to do. Going by ATS
past database fixes, this is something electrical. What
am I missing here?
Did you check your 5 volt vref? The symptom you gave matches this problem and this vref wiring is critical. If
missing, none of your sensors will work and of course the ecm is disabled. Use the ecm wiring diagram to find it.
The vref wire is called VC and it uses a blue color wire. When checking the ecm wiring terminals, it is located on
To check this voltage, put your ignition at koeo and measure the vref at pin 30. If you can disconnect it
to isolate the sensors that is OK because I have some mechanics cut this line to check the vref. If
disconnected and you see the ecm communicating with your scanner, it is just a matter of disconnecting each sensor
one by one until the vref is restored. The sensors might be OK but it is also possible that one of the vref wire
is open/shorted to the sensor.
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