Help me identify problem?

Hi all, I am having a couple of small problems with my '09 TRD off road and figured you guys may know what to look for.
This is what I have noticed:
- ABS light remains on when driving
- Traction controlled light remains on while driving
- Brake light is not working unless we fiddle with brake switch, then it works some of the time, but eventually stops again.
- Automatic often stuck in park, I have to release it with the small button beside shifter

I know this points to perhaps some sort of electronic issues with the brakes. So I got my friend to read the codes and we found the following:

- C1246 Toyota ABS malfunction in master cylinder pressure sensore
- C1256 Toyota ABS Accumulator low pressure malfunction
- C1440 Toyota ABS steering angle sensor unusual bank angle detected (prob from off-roading)

Any ideas on what to look at?
Thanks guys, much appreciated

 

First get your brake light switch fixed down on the brake pedal. That will take care of most if not all of your problems.

That will cause the Shifter lock to not unlock. The codes are causing the Traction Control And ABS Lights to remain on.

I think the low pressure faults are from the ECU thinking that you are pressing the brakes, but it is not seeing the pressure.

 

I agree with Jimmy. Start with the simple stuff first is what I always do, it often clears up other issues. Take it from someone who makes a living repairing stuff, overanalyzing the problem will often lead you in the wrong and more expensive direction. My guess is the brake switch or a wire going to it has a break inside the insulation.

 

Thanks guys....I'll order a new one and see what that does.

 

So when we tinker with the current brake switch, it seems to work fine, especially when manually pressing it in. I suspect it has something to do with the brake switch not properly activating during the depression of the brake pedal. Has anyone had this issue?

 

Yes they have that is why we are telling you to get it working properly and most if not all of your issues will disappear.

The stop light switch ( Normally Open ) is tied into the Skid Control ECU ... when you depress the brake pedal it completes the circuit for the brake stop lights and sends a signal to the Skid Control ECU.

 

Did you ever figure out what the c1440 code was for? I also have a c1256 and c1201 code but I believe I have a leaking rear brake cylinder that's causing those codes( I hope that's it.)

 

Didn't see a C1440 listed.

Here is some information about it:

https://www.engine-codes.com/c1440.html

C1256/56 Accumulator Low Pressure

http://www.customtacos.com/tech.old...06toyrm/06toypdf/06rmsrc/rm2006ta/0410052.pdf


C1201/51 Engine Control System Malfunction

http://www.customtacos.com/tech.old...06toyrm/06toypdf/06rmsrc/rm2006ta/0410038.pdf

 

So if the c1256 is a low pressure warning could it be due to a leaking rear wheel brake cylinder? Looked underneath the truck and the right rear drum was wet and oily... I can only assume a replacement will be in my very near future.

 

If the master is regularly losing level that would support the idea of a leaker. Which obviously pulling the drum and looking is the real way to know.

If the master is steady in level, wet and oily looking under the truck could be something else. Like an axle seal.

 

What Bill says!

Also a minor leak on the wheel cylinder should not give you a low accumulator pressure unless the master cylinder has ran dry and you have air in the system...

 

Silly question but how do you check the following?

• Faulty Hydraulic Control Unit (HCU)

• Hydraulic Control Unit (HCU) harness is open or shorted

• Hydraulic Control Unit (HCU) circuit poor electrical connection

 

Scan the abs/trac system for codes. If codes are present then you have a problem. But, I'm guessing you already have code(s)

With everything plugged in and the key on do some voltage drop tests along the harness

Or

Disconnect the harness at both ends and do some resistance/continuity tests

These tests require a dmm

Visually look at the connector and pins for damage.

Sounds like you got some codes pulled for free at a parts store and they sent you home with one of those sheets that describes the code and the possible causes.

 

Will do. Thanks a ton.