The Toyota service manual says to test the B+ and HT terminals for resistance in the oxygen sensors. I got the connector apart and there are four posts on the sensor side. No markings inside or outside to which is B+ or HT. Can anyone help me figure which posts to use?

The manual says this test has to be done within 90 seconds of the key going to LOCK and the negative battery cable disconnected. I can buy into the 90 seconds, but why disconnect the battery if the oxygen sensor is unplugged. Is this the standard safety practice advised by the legal department?

Thanks
dmend

1995 Camry wagon 150,000 miles
1996 Camry wagon 100,000 miles
2002 Camry sedan 65,000 miles

 

V6 engine?

You can only check for resistance of the heater.

Depending on which sensor you have the HT wire is either:

Blue/Black
Pink/Black
Violet/Red

The B+ is:

Brown/Orange

Not sure of the 90 second issue. This is a standard line when working in the area of the airbags. The battery needs to be disconnected for 90 seconds to disarm the airbag system.

Never heard of this requirement to test the O2 sensors.

 

Yes, its a V6.

It has 3 oxygen sensors and only one is conveniently located.

The 90 seconds for the air bag is what I was taught in a Steering and Suspension class. In toyota manuals it seems like they tell you to disconnect the negative battery cable no matter what you do, with exception of changing a tire.

The tool is a multi-meter. I've read that the cheap multi-meters won't give an accurate reading. I've a decent brand for a home garage, so it's worth a try to see what results I produce.

Thanks for for the wire colors.

Dmend