A/F stands for Air/Fuel, this is the sensor also known as an "Oxygen sensor" this sensor contains a heating element.
The fact that the fuse panel does not have a fuse in this position might be meaningless, since the fuse panel may be a holdover from another year/model.
HTH
JerryR

 

A/F stands for Air/Fuel, this is the sensor also known as an "Oxygen sensor" this sensor contains a heating element.
The fact that the fuse panel does not have a fuse in this position might be meaningless, since the fuse panel may be a holdover from another year/model.
HTH
JerryR

Thanks for the reply!

I am familiar with oxygen sensors, having replaced both of the ones on my 1996 Camry. I somehow must have not become familiar with the abbreviation A/F sensor and A/F heater during that process.

An excellent point to consider re: the possibility that the fuse box and lid markings possibly not being accurate for my particular car. However the owner's manual show the 25A A/F heater fuse also, so it apparently confirms that I'm supposed to have a fuse there.

[brief time out to go out and inspect the fuse area closely]

So much for fuse box lid and owner's manual equalling confirmation.

Close inspection of the slot where the 25A A/F Heater fuse is supposed to go reveals that the slot is blank -- there are no metal contacts down at the bottom to accept the blades of the fuse .As metal contacts can clearly be seen down at the bottom of the several other fuses I pulled to check, I'm going to go with your original idea that the fuse case cover markings AND the owner's manual are incorrect.

Actually a bit unsettling considering that I had always considered those items accurate and to be relied on in situations where I really didn't know what I was doing ...

Thanks for your help and for your "out of the box" advice (for me) turning out to be the solution!

Ladd

 

Thanks for the reply!

I am familiar with oxygen sensors, having replaced both of the ones on my 1996 Camry. I somehow must have not become familiar with the abbreviation A/F sensor and A/F heater during that process.

An excellent point to consider re: the possibility that the fuse box and lid markings possibly not being accurate for my particular car. However the owner's manual show the 25A A/F heater fuse also, so it apparently confirms that I'm supposed to have a fuse there.

[brief time out to go out and inspect the fuse area closely]

So much for fuse box lid and owner's manual equalling confirmation.

Close inspection of the slot where the 25A A/F Heater fuse is supposed to go reveals that the slot is blank -- there are no metal contacts down at the bottom to accept the blades of the fuse .As metal contacts can clearly be seen down at the bottom of the several other fuses I pulled to check, I'm going to go with your original idea that the fuse case cover markings AND the owner's manual are incorrect.

Actually a bit unsettling considering that I had always considered those items accurate and to be relied on in situations where I really didn't know what I was doing ...

Thanks for your help and for your "out of the box" advice (for me) turning out to be the solution!

Ladd

Thanks for writing. I have the same fuse missing on my 2000 CE. I haven't looked closely enough to see if there are actual metal contacts there so I will not be putting a fuse there until I check. I have had no problems or codes because of it and have beeen driving the car for 10 years.

 

Thread moved from the Lounge.

 

Is your car a non-california emissions v6? Only the California emissions cars use AF sensors, the federal emissions use O2 sensors and don't have these fuses or relays populated.

 

While studying the electrical system on my Gen3 there are two fuse boxes under the hood. One of them is completely empty, except for a single relay (all of the rest of the holes are unpopulated). The several empty holes were for a bunch of Canada running lights and for California emissions things (none of that wiring is present).
Then, I looked closely at the fuse panel below the steering wheel and noticed it is fully populated, but at least 3 of the 12 fuses are unused in my car (mine doesn't have power seats, or a few other things), but they gave away the fuses, I guess for wire harness variation control in the plant.

The fully stocked panel under the dash "looks" better than the "bare shelves" one under the hood.

What is really interesting is to study and find "give away" circuits to make use of. The FJ cruiser came with a whole host of "easter eggs" like that (features you could add by simply installing a missing switch, or a second horn ready-wired, give away harness for driving lights, and things like that).

Recently I wanted to add a GPS tracker to a Toyota, and found a red/white wire (+12V always powered), with a white/black (ground) in an unused wire harness connector, just sitting there, in a nice out of the way place. I never did find out what option it had been originally meant for, but it made for a very tidy installation for my stealth tracking solution (simply buy the mating connector from a dealer, and a pair of patch wires to go in it).

 

This isn't super on-topic so sorry for that.

By give away circuits do you mean ones that are wired up to a fuse/relay box connected to a harness but don't actually go anywhere that you can use to hardwire things into the car rather than ghetto splicing solutions, etc?

Also I would love to hear more about the tracker you added, that's something I've been thinking about doing for a while now but don't have much experience with electrical systems so I've been kind of scared of jumping into that or hardwiring other things in.

Does it connect using a SIM to LTE connection or something? Is there a monthly/annual cost for the service?

I've thought about using an old cellphone encrypted and locked down with android find my phone enabled and running 12v dc charger to it behind the dash as a ghetto tracking solution, but a tiny pcb with a sim card would be a lot harder to spot especially in my car.

 

There are dedicated trackers available, from many sources, for only about $40. There are cell phone based ones, and also GPS based ones. The appeal of GPS is it isn't limited to only where cell service is available. The purchase is pretty cheap, but of course there is also a service fee, but you can get a discount if using multiple ones, or if you pay for a year in advance.

The software that comes with it is key, you can see breadcrumbs (where the vehicle has been each day) and you can locate at any time. Mostly, it is just nice to set an alarm (and a geo fence) to alert you if it is ever moved, while you have it in storage somewhere and the battery tender on the car keeps the GPS charged, so long as you've hooked it to a wire with constant voltage, like the red/white stripe wire in Toyota's systems for radio memory, hazard lights, clock power and door lock (examples of where you can tap into it).

They do need a dedicated power supply, or you'll have to remove it every few days to recharge.

There are really cheap ones that plug into the OBDII port, but that would be the first thing a thief would disconnect so of little use for things like that. Hidden deep within the car, permanently wired, with nothing visible is the best way for security.

"By give away circuits do you mean ones that are wired up to a fuse/relay box connected to a harness but don't actually go anywhere that you can use to hardwire things into the car rather than ghetto splicing solutions, etc? " - exactly. Usually someone who finds one will post it on a forum like this and by searching you can find them. On a Camry there's not much, but on a truck there can be a lot. Most often, all they are good for is adding a feature your car didn't come with.

 

I also have a 2000 Toyota Camry CE and I also do not have the A/R HTR fuse

 

You can put a fuse in there but there's nothing to really plug it into. In other words it's a blind slot sans an electrical connection.