I am getting code 1647 for the upstream air fuel mix sensor. I’ve read in some of the posts to be sure and check fuses first But I do t see a fuse specifically for the sensors. Am I missing something? I’ve ordered the Denso 234-9029 on Amazon but while its coming thought I would try and check for fuses too. Is there a fuse? Thanks

 

Being a 2004, is mfg date prior to April or after. It makes a difference on the fuses (2004 vs 2004.25). Either can be downloaded from the main page "stickies"

38 & 42 versus 20 & 21 hood/bonnet fuse box

 

Fuses in Engine compartment on mine for 20 and 21 are labeled Oxygen Sensor A for 21 and Oxygen Sensor B for 20. But isn’t the faulty part I am getting for fault code 1647 technically called a fuel air mixture sensor and not O2 sensor? I can’t find reference for an air fuel sensor in the fuses diagram. I have also verified fuses 20 and 21 which are green 30 are good and have continuity across them

 

Heated O2 sensor technical name is fuel air mixture sensor

An oxygen sensor (or lambda sensor, where lambda refers to air–fuel equivalence ratio, usually denoted by λ) is an electronic device that measures the proportion of oxygen (O2) in the gas or liquid being analysed.

It was developed by Robert Bosch GmbHduring the late 1960s under the supervision of Dr. Günter Bauman. The original sensing element is made with a thimble-shaped zirconia ceramic coated on both the exhaust and reference sides with a thin layer of platinum and comes in both heated and unheated forms. The planar-style sensor entered the market in 1990 and significantly reduced the mass of the ceramic sensing element, as well as incorporating the heater within the ceramic structure.[1] This resulted in a sensor that started sooner and responded faster.

The most common application is to measure the exhaust-gas concentration of oxygen for internal combustion engines in automobiles and other vehicles in order to calculate and, if required, dynamically adjust the air-fuel ratio so that catalytic converters can work optimally, and also determine whether the converter is performing properly or not

 

Ok thanks, so since my fuses check ok I will wait until new Denso part comes and swap it out and clear codes. Hope that solves the error code

 

Just finished swapping out the sensor and cleared codes. So far so good , no error codes coming on and no check engine on dash. Your experience may vary but I had to use a deep well version of sensor socket to get down past the heat shield t9 take out old sensor part. Also used a length of pipe over ratchet for leverage since it was very tight. I did remove air box, snorkel and battery box to be able to get at everything then had easy access. Spent longer looking for a battery box hold down bolt that slipped and fell than swapping the sensor.

 

Dandy