Stuck Brake Fluid float/sensor on 2009 Tacoma

2009 TRD DCSB 4x4 175k miles

A couple of months ago, I let my brake fluid get too low and the brake light/slip indicator light showed up on my dash. I refilled the brake fluid and eventually replaced the rear pads.

I read that I needed to clear the codes using Techstream, so I bought a full setup of the software on a laptop. I am getting the following code: C1202 Brake Fluid Level Low/Open Circuit in Brake Fluid Level Warning Switch Circuit.



I cleared the code, but it immediately popped back up, so I printed out the procedure from the FSM to troubleshoot the issue.

I unplugged/plugged back in several plugs, but haven't started replacing any parts yet. I don't have an electrical tester on me at the moment, but plan to pick one up to diagnose farther.

I doubt the sensor itself is bad, because it kicked on when the fluid was low. I suspect the float is stuck. My driveway is a pretty good incline, so I could see it getting jammed up when I refilled it.

Has anyone else had this same issue?

 

Do you have normal braking; a good, firm pedal? Low fluid always takes my mind right to 'air in the system'.

 

The brakes were properly bled and feel like perfectly normal nothing special Tacoma brakes.

 

Any way you can get a small pick in there and gently tug at it?

 

I didn’t have one small enough.

I’m going to go full send and hit it with a rubber hammer....

This is the TRD $$$$$ brake system, so maybe I’ll just go half send.

 

You need to check pin1 white /black wire at the fluid level sensor for ground, if the ground is missing you need to find the broken wire or give it its own ground.

 

Odd that the brake fluid would get low without a leak.

 

The switch below does NOT apply to truck with VSC.

I have a question?
What type of switch is this?

It looks like the switch has a resistor. When the fluid is full it goes through the resistor?
If the fluid is low, the switch closes and the resistor is “bypassed”?

Is the correct?

 

I think the resistor is there for the skid control ECU to verify circuit integrity, otherwise it wouldn't know if the sensor was unplugged. I almost got my butt kicked by a Camry hybrid because of that till I realized the resistor had to be in the circuit or it would flag a code, it ended up being a broken ground wire going to the fluid level sensor.

 

That makes since, I had never thought of that.
Thanks for the explanation

 

NP, Toyota is the first manufacturer I've ran into that uses a level switch with a resistor most just use a simple on/off switch.

 

It is a standard practice to use this method ( rare ) or a normally closed switch ( more Common ) in a safety circuit. That is so that an inadvertently cut wire or an open in the safety circuit can be detected and an alarm given.

 

I picked up a nice Klein multimeter at Home Depot and diagnosed the issue.


When I mentioned earlier that the fluid was low, it was barely low, and depending on how the truck was sitting, likely wasn't low enough to trigger the sensor.

I bought a replacement reservoir for $95. Not that anyone cares, but I'll circle back and post if it fixes the issue.

 

So you had a low resistance reading with the float up. Less than 10 K Ohms.

 

I had to zoom in on DVOM to make sure it was on K/ohm.
Because as you stated, it is LOW

BTW, I’ve been victim of the Auto Range feature.
Always double check.

 

Since I have gotten Cataract surgery in both eyes I don't need to zoom in very often. LOL

 

I’m not quite there yet.
I did have LASIK about 18 years ago.
I don’t want to think about contacts or glasses for a long time.
I wore them all through school. My graduation gift form my family was LASIK.

 

I had them install corrective lenses with blueblocker filters so I don't have to wear glasses anymore!

 

Well, I figured out I'm a dummy that wasted money on the reservoir. It didn't fix the issue, and after looking at the paperwork, it was actually within specs all along.

The B2-1 to B2-2 connection on the new reservoir reads 1.944 and the one I took off read 1.966. That was wasted money.







The reading on this one is hard to get, but it bounces between 0 and 0.2. This is also in spec.





I cleared the code in Techstream and it immediately reappears. According to the Factory Service Manual, my next step is to replace the Master Cylinder Soleniod. My truck has the TRD Offroad Package and this part is astronomically expensive.

If anyone one has suggestions on other thing to troubleshoot, I'm all ears.

 

BTW, the reason I ended up buying the reservoir is the service manual paperwork I was referencing before was for the wrong model.