ABS codes 31 and 36 (1 Viewer)

[Seadoobie]

I’ve pulled the sensors and cleaned them and traced all the wiring and can’t see any signs of damage. I’ve checked the FSM and it says to test the speed sensor connector. Can someone please point me in the right direction to find which of the many connectors this might be? All the wires and connectors near the ABS are tucked in nice and neat and I don’t want to start hacking them apart trying to see which connector to test. Also, would love any input of other possible things I could check. I’m not the greatest with electrical but with a little hand holding I could probably narrow this down. Really don’t want to buy a whole new harness for close to $600 and the pain of removing/installing.

Thanks!

 

[Malleus]

I’ve pulled the sensors and cleaned them and traced all the wiring and can’t see any signs of damage. I’ve checked the FSM and it says to test the speed sensor connector. Can someone please point me in the right direction to find which of the many connectors this might be? All the wires and connectors near the ABS are tucked in nice and neat and I don’t want to start hacking them apart trying to see which connector to test. Also, would love any input of other possible things I could check. I’m not the greatest with electrical but with a little hand holding I could probably narrow this down. Really don’t want to buy a whole new harness for close to $600 and the pain of removing/installing.

Thanks!

View attachment 3273649

The housings pictured above are the sensors on the wheels.

Although the illustrations above all indicate using the ABS sensor mounting bolts as grounds, I'd check them to ensure they are actually good, clean grounds, before using them as such.

This procedure will help you identify a bad sensor. Checking the harness is a different procedure; you'll be checking the length of the wire from the wheel to the ABS computer. However, I'd check the harness last, because it's so much more difficult to check than the sensors and computer.

Also, what year are you working on? I attached the ABS troubleshooting section for the 1995 (which is the same for '95-'97 and all LX450). It's pretty self explanatory.

 

[Seadoobie]

The housings pictured above are the sensors on the wheels.

Although the illustrations above all indicate using the ABS sensor mounting bolts as grounds, I'd check them to ensure they are actually good, clean grounds, before using them as such.

This procedure will help you identify a bad sensor. Checking the harness is a different procedure; you'll be checking the length of the wire from the wheel to the ABS computer. However, I'd check the harness last, because it's so much more difficult to check than the sensors and computer.

Also, what year are you working on? I attached the ABS troubleshooting section for the 1995 (which is the same for '95-'97 and all LX450). It's pretty self explanatory.

Thank you! Mine is a 96 LX450. Sorry, forgot to add that. I’ll check the these out now.

 

[Malleus]

You can find all the electrical info you need in the Resources section, as well as a complete FSM. For generic info a 1996 Land Cruier FSM will work for you. There are a few LX specific items that will only be in the LX450 FSM, so it's best to get that one, along with its EWD. The wiring harness repair manual is very helpful, and it's not specific to any Toyota. Up to the year it was published.

 

[Seadoobie]

You can find all the electrical info you need in the Resources section, as well as a complete FSM. For generic info a 1996 Land Cruier FSM will work for you. There are a few LX specific items that will only be in the LX450 FSM, so it's best to get that one, along with its EWD. The wiring harness repair manual is very helpful, and it's not specific to any Toyota. Up to the year it was published.

Thanks. That’s why I posted a screenshot from my copy of FSM. I’m using it to troubleshoot. But it references connectors as if you already know every single connectors exact location and what it connects to and what it looks like. I don’t. Maybe I missed another spot in the FSM that showed pics of where the connectors it tells you to test are. There’s a million of them on this truck. Just hoping someone might already know where is the one I need to test.

 

[Malleus]

Understandable. Did I answer your question?

Generally, when the FSM indicates a connector test, it means the connector on the sensor. If you need to test the harness, it'll say so:
(for example)

 

[Seadoobie]

Understandable. Did I answer your question?

Generally, when the FSM indicates a connector test, it means the connector on the sensor. If you need to test the harness, it'll say so:
(for example)
View attachment 3274320

Thanks again for taking the time to help. Maybe it’s different on different models, but on this 96 LX450 there are no connectors at the front ABS sensors. It’s one wire loom with no connection except for on one end. Both front sensors are built into that sealed harness.

 

[Malleus]

Now the diagnostic instructions make sense. You are to check the connector at the end of the sub harness - the black one at the bottom of the photo. Terminals 1/3 are positive and negative for the right sensor, respectively, and 2/4 are positive and negative for the left sensor.

I assume the rear sensors are wired separately from each other with a long pigtail?

So, with respect to which lead to connect where, in this test, it doesn't matter. If you get the polarity wrong, the display will be negative in stead of positive. You're measuring resistance (actually verifying that the circuit is complete), so all you care about is the absolute value of the number. This test should be done with the sensors installed on the truck.

Generally, you want the red lead to be positive and the black to be negative.

And yes, the Land Cruisers are wired differently. The ABS sensors at the wheels are separate pieces.

HTH

 

[Seadoobie]

Now the diagnostic instructions make sense. You are to check the connector at the end of the sub harness - the black one at the bottom of the photo.

And yes, the Land Cruisers are wired differently. The ABS sensors at the wheels are separate pieces.

Just have to figure out where it is on the vehicle. I think it’s near your left foot when in the drivers seat?

 

[Malleus]

Follow one lead from under the truck; start at either front wheel. The harness connector will likely be under the truck.

 

[Malleus]

This is from the 1996 LX450 EWD:

The ABS ECU is in the front left kickpanel. This diagram doesn't identify the front sensor's harness connector location.

 

[Malleus]

The 1996 LX450 FSM I have doesn't include a component location diagram like the Land Cruisers have:

 

[Seadoobie]

The 1996 LX450 FSM I have doesn't include a component location diagram like the Land Cruisers have:
View attachment 3274392

You’re awesome! I’ll dig in tomorrow and see if I can narrow this problem down. Although today I figured out that my bulb for the center diff lock was out and when I replaced it, it was permanently on. So there’s an issue with the center diff lock that may be causing the ABS problem.

 

[ppc]

So there’s an issue with the center diff lock that may be causing the ABS problem.

Just to verify that you know the CDL dash indicator, ABS dash light and ABS system disabling are all controlled by the CDL sensor switch on the front of the transfer case. That sensor switch only mechanically senses the position of the locking arm. There is no electrical connection to other components of the system including the 4LOW position sensor on the rear of the transfer case, the CDL dash button, the CDL actuator or CDL relay.

 

[Seadoobie]

Just to verify that you know the CDL dash indicator, ABS dash light and ABS system disabling are all controlled by the CDL sensor switch on the front of the transfer case. That sensor switch only mechanically senses the position of the locking arm. There is no electrical connection to other components of the system including the 4LOW position sensor on the rear of the transfer case, the CDL dash button, the CDL actuator or CDL relay.

Thank you for that. So does that likely indicate I’ll need to replace the actuator motor? For some reason it thinks the CDL is engaged when it is not. At least I don’t think it is. I haven’t noticed any issues on tight turns. I’m going to use the ‘Jack the front tire up and see if it spins in neutral’ method tomorrow and confirm.

 

[ppc]

Thank you for that. So does that likely indicate I’ll need to replace the actuator motor? For some reason it thinks the CDL is engaged when it is not. At least I don’t think it is. I haven’t noticed any issues on tight turns. I’m going to use the ‘Jack the front tire up and see if it spins in neutral’ method tomorrow and confirm.

If you don't think the CDL is on continuously then I don't see any reason to mess with the actuator. First thing you need to do is unplug the sensor switch on the front of the transfer case. If things are working properly then the CDL Dash light should go off. If not, then considering the ABS fault codes indicate there is a problem with that system then that is where you need to debug and expend your efforts. In a fully functioning system the CDL sensor provides a ground path that lights both the CDL and ABS dash lights. It's entirely possible that the ABS ecm fault is providing a similar ground path.

 

[Seadoobie]

The 1996 LX450 FSM I have doesn't include a component location diagram like the Land Cruisers have:
View attachment 3274392

Looks like this may be it:

 

[Malleus]

It may be; the diagram I posted was for the Land Cruiser.

 

[The299]

Did you end up finding the Bd1 connector?

I do also have the 31 code and can’t find it even after looking in the EWD. In The drawing looks like it is in front of the firewall but the description says kick panel

 

[stefan]

Hi all, for those looking for an answer where this connector is (like i was doing), the connector that goes to the front abs sensors. I found this in my car inside the left front fender. Behind the red box in the picture. I got to the connector from below. My car is 1994 diesel automatic.

I had also the codes 31 and 36 and the problem was in the connector that plugs into the front right sensor, it was damaged.