2 Wire Hall Effect Wheel Speed Sensor Usage

[DO1023]

Hello all - I'm utilising wheel speed sensors from a 2002-2011 Toyota Camry and 2006-2012 Toyota Rav4 wheel speed sensors in my MR2 Time attack car.

I'm having trouble getting these to read on the link ecu. I've tried a variety of configurations. These are currently wired to DIs. 

I believe these are two wire hall effect sensors ( but am not 100% sure ). Is there something I'm missing? Would really like to have traction control in the car as it's rather powerful.
 

 

Any tips? 

[koracing]

Two wire sensors tend to be VR (reluctor) - have you put an actual oscilloscope on them to see what signal is being sent to the ecu pins when you spin the wheel?

[DO1023]

46 minutes ago, koracing said:

Two wire sensors tend to be VR (reluctor) - have you put an actual oscilloscope on them to see what signal is being sent to the ecu pins when you spin the wheel?

Unfortunately not. This is actually the first I've heard of such a word. Does the ECU not have this feature on DIs? 

[koracing]

The Trigger scope function does monitor the first 4 DI inputs if you run a trigger test while spinning a wheel, but it doesn't actually show you the shape of the wave form like a real oscilloscope would, rather just a active/inactive square wave looking pattern when set up properly.  Conversely you could attach the sensor inputs to Trig1 or Trig2 inputs and those do show wave-form like a real scope and you could use them using the capture function while spinning the wheels manually (or having a friend spin the wheels) - obviously the vehicle can't run in this situation and you would want to be careful to make sure injectors and ingition are disabled just in case while performing this testing.

[DO1023]

4 minutes ago, koracing said:

The Trigger scope function does monitor the first 4 DI inputs if you run a trigger test while spinning a wheel, but it doesn't actually show you the shape of the wave form like a real oscilloscope would, rather just a active/inactive square wave looking pattern when set up properly.  Conversely you could attach the sensor inputs to Trig1 or Trig2 inputs and those do show wave-form like a real scope and you could use them using the capture function while spinning the wheels manually (or having a friend spin the wheels) - obviously the vehicle can't run in this situation and you would want to be careful to make sure injectors and ingition are disabled just in case while performing this testing.

Hm that will be difficult as my harness is pretty much fully sealed. Is this just a case of maybe the wheel speed calibration is off?

[Vaughan]

4 minutes ago, DO1023 said:

Unfortunately not. This is actually the first I've heard of such a word. Does the ECU not have this feature on DIs? 

VR or reluctor sensors output a waveform that varies in amplitude (voltage) depending on how fast the item is spinning. Often with VR wheel speed sensors connected directly to the ECU you need to get the wheel speed up over 20 or 25kph before the voltage on the signal gets high enough for the DI pins to read it (over 1.8V).

The ECU can show you the raw frequency it is seeing but not the actual waveform on that pin as koracing mentioned.

There are also 2 wire hall sensors that exist (commonly on 2000s Nissans and newer vehicles) which are a massive pain to setup as they rely more on a current flow trace rather than a voltage trace and so can require lots of trial and error to get the right hardware around them before the signal received by the ECU is usable.

As a side note I'm using the factory VR sensors in my MR2 connected directly to the ECU and they show up and operate correctly above 20kph.

Just now, DO1023 said:

Is this just a case of maybe the wheel speed calibration is off?

If you are not seeing a frequency on the specific DI's Frequency runtime and it is set up as a frequency or speed input then the only setting you can change in the ECU is the pullup which is always off for VR sensors but can be off or on for Hall sensors.

[DO1023]

I got the wheels to 70kph ( as verified by my trans VSS ). I haven't viewed the frequency so I'll try that. 

These sensors are used on the wilhelm knuckles and supposedly work well with the stock MR2 ABS so I imagined they would still work fine?

[Vaughan]

8 minutes ago, DO1023 said:

These sensors are used on the wilhelm knuckles and supposedly work well with the stock MR2 ABS so I imagined they would still work fine?

This would suggest they are VR sensors not hall sensors, do you have the DI pullups turned off?

[DO1023]

Okay I just watched frequency. No data all the way up to 70kph. I've tried pullups on and off.

okay edit just popped a sensor out. Put a magnet to it, No frequency change.

 

 

 

Someone I know seems to think you have to have a VR to hall effect sensor converter and that works for them. So perhaps I should do that.

[Vaughan]

28 minutes ago, DO1023 said:

I've tried pullups on and off

Pullups have to be off for VR sensors.

28 minutes ago, DO1023 said:

Someone I know seems to think you have to have a VR to hall effect sensor converter and that works for them. So perhaps I should do that.

VR to hall effect converters mean you can read the VR values at lower speeds as they amplify the signal to a set voltage and convert it to a square wave but they are not required to make the signal work at higher speeds.

 

Maybe attach a copy of your tune so I can check it is setup correctly, otherwise get an oscilloscope on the DI pin to see what signal it is actually receiving.

[Adamw]

I suspect these will be magnetoresistive sensors.  I didnt look for info on the camry, but the info below is from a 3rd gen rav4 manual.  You can see it shows a squarewave signal with 2 different current levels.  

So these would need the matching RAV4 magnetic target wheels and wouldnt work with stock MR2 ABS.  

They can be quite tricky to make work, you need to experiment with different combinations of supply voltages and pull-up/down values to convert the variable current into a variable voltage.  The fixed switching thresholds of the G4X DI's often arent well suited for this type of sensor.  Some basic info here:   https://www.motec.com.au/filedownload.php/CTN0007 Magneto Resistive Sensors.pdf?docid=3634

[DO1023]

1 minute ago, Adamw said:

I suspect these will be magnetoresistive sensors.  I didnt look for info on the camry, but the info below is from a 3rd gen rav4 manual.  You can see it shows a squarewave signal with 2 different current levels.  

So these would need the matching RAV4 magnetic target wheels and wouldnt work with stock MR2 ABS.  

They can be quite tricky to make work, you need to experiment with different combinations of supply voltages and pull-up/down values to convert the variable current into a variable voltage.  The fixed switching thresholds of the G4X DI's often arent well suited for this type of sensor.  Some basic info here:   https://www.motec.com.au/filedownload.php/CTN0007 Magneto Resistive Sensors.pdf?docid=3634

Interesting. We do use rav4 in the front. So should I do the vr to hall effect converter?

[DO1023]

Okay just verified some things. Not the RAV4 sensors.

2006-2011 Camry in the rear

2002-2011 Camry in the front

 

[Adamw]

I found a couple of service manuals for a XV40 camry, both of them suggest they have normal VR/AC wheel speed sensors.

 

But then a google image search suggests there may not all be that type.  Both these pics below are for XV40 camry front wheel speed sensors.

If your sensors look like this one with a cylindrical body and a pole piece visibly poking out the end in the centre then I would say that is almost definitely VR.

However if it looks more like a flattened blade like this one below, then I would lean more towards it being an MR/Active type.

[DO1023]

12 minutes ago, Adamw said:

I found a couple of service manuals for a XV40 camry, both of them suggest they have normal VR/AC wheel speed sensors.

 

But then a google image search suggests there may not all be that type.  Both these pics below are for XV40 camry front wheel speed sensors.

If your sensors look like this one with a cylindrical body and a pole piece visibly poking out the end in the centre then I would say that is almost definitely VR.

However if it looks more like a flattened blade like this one below, then I would lean more towards it being an MR/Active type.

Ah yes- looks like the first image... 

So this indicates it should work no? I'm not sure whats up...

Here's how its wired.

I understand this could possibly be reversed accidentally.

Wheel speeds go:

1 Wire into a sensor ground. Pin 24 of the " A " Plug on the ecu. ( shared amongst the two rear wheel speeds )
1 Wire to a DI

[DO1023]

Here's a link to the tune file. Sorry for the delay - I was not near the car at the time

https://drive.google.com/drive/folders/1aBbVYknEOh7UQL-exFa54tC_bqmodnc4?usp=sharing

 

It's notable to mention I am using DI 7/8 for the rears.. docs say VR sensors can be used for DI 1-4 but nothing about anything beyond that. Perhaps thats the issue?

[Vaughan]

13 minutes ago, DO1023 said:

Here's a link to the tune file. Sorry for the delay - I was not near the car at the time

https://drive.google.com/drive/folders/1aBbVYknEOh7UQL-exFa54tC_bqmodnc4?usp=sharing

The front sensors have the pullup on in your tune file, the rears do not. If they are all VR sensors then the fronts should have the pullups turned off.

To confirm the the 'DI 7 Freq' and 'DI 8 Freq' don't show any value other than 0Hz while those wheels are spinning at over 25kph?

[DO1023]

Yeah sorry that was from me playing around a bit. I've been focusing on the rears. And those freq channels have " NO DATA" , not 0hz

[Confused]

NO DATA means that you're not logging these parameters.

Make sure that you have every single parameter added for PC Logging by clicking the "Add All >>" button:

[DO1023]

I'll try that today. I would imagine that viewing the runtime value for the input would show a value whether I am logging or not? My mistake.

[DO1023]

Attempted the above. There was no change unfortunately. Will try the converters as I've seen others do with these sensors and see what happens 

[Vaughan]

You really need to get an oscilloscope on it so you can see what the signals are doing

[DO1023]

10 minutes ago, Vaughan said:

You really need to get an oscilloscope on it so you can see what the signals are doing

I'm just gonna do the silly thing and do the converters first. It's simple enough to do and it's confirmed working with these sensors.

 

If that doesn't work the oscilloscope it is.

 

 

Is there any truth that beyond DI 4, You can't do VR wheel speed? It's just a thought from reading the docs, not conclusive so I figured I'd ask.

[Vaughan]

1 minute ago, DO1023 said:

Is there any truth that beyond DI 4, You can't do VR wheel speed? It's just a thought from reading the docs, not conclusive so I figured I'd ask.

You have to use DI1-4 for VVT sensors (as the exact engine angles the signals occur at is important) but there is no issue with using any DI for a VR frequency input.

[DO1023]

6 hours ago, Vaughan said:

You have to use DI1-4 for VVT sensors (as the exact engine angles the signals occur at is important) but there is no issue with using any DI for a VR frequency input.

Very weird. I'll report back what I come up with. Thanks for all the help thus far.