20 Most Recent 2003 Toyota Sequoia - Page 7 Questions & Answers

Drive it for about 50 miles of mixed driving types to clear this up.

tells me nutting come on people post problems!!!Go to there web site for answers.

P1203 is injector cylinder number 3 its either open(disconnected) or shorted,

DIY people can buy a kit at the parts store and add a can or two if the system is just low.The kit is a gauge and hose that connects to one of the service ports on the ac line and takes the cans of freon.Freon gas is about minus 30 degrees coming out of the can.

The question is not so much if you are able to replace the O2 sensor, but rather is the O2 sensor faulty.The sensor is screwed into the exhaust pipe in front of the cat.The computer reads the sensors in front and after the cat to make sure the cat is working among other things.An ignition or injector problem could cause a false reading from the O2 sensor. A tech would take a scanner that reads live data and look at what the sensor is producing to decide if the sensor is bad.You could buy a sensor and install it only to find you have a different problem upstream.

It is in the rear behind the trim panel.