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Active ABS tool #

Posted by Chris Hogan on February 21, 2011, 5:11 pm

Year of Manufacture *: 2000

would anybody know where i can pick up a tool for testing active abs sensors or the best way to scope them !!
thanks chris

Re: active abs tool

Posted by Mark carter User icon on February 21, 2011, 7:32 pm, in reply to "active abs tool"
Mark Carter

Hi Chris,
Honest answer,understand how they work (they are not all the same) and then Scope them.

regards mark

Modern cars, Its all wizardry and witchcraft

Re: active abs tool

Posted by chris hogan User icon on February 22, 2011, 11:44 am, in reply to "Re: active abs tool"
Christopher Hogan

easier said than done autodata bosch esi dont have any info or it is not covered
nissan make a tool
NISSAN: ESSENTIAL TOOL; J-45741 ABS
ACTIVE WHEEL SENSOR CHECKER
if you dont know the signal values how do you scope it you could use the values off the other sensors assuming they are good

thanks for the reply

Chris

Re: active abs tool

Posted by Mark Mcgrath User icon on February 22, 2011, 2:23 pm, in reply to "Re: active abs tool"
Mark McGrath

check your email

Re: active abs tool

Posted by Mark carter User icon on February 22, 2011, 6:04 pm, in reply to "Re: active abs tool"
Mark Carter

Hi chris, good point.

With a scope set to single ended measuring, look at a good one on the vehicle and compare it to the one the ECU does not like.
Because it is a digital signal you are not looking for a amplitude change, just a square wave on/off signal.

HTH

Regards mark

Modern cars, Its all wizardry and witchcraft

Re: active abs tool

Posted by Alan Kane User icon on February 22, 2011, 6:32 pm, in reply to "Re: active abs tool"
Alan Kane - Administrator

Just to show the effectiveness of scopeing these, here is an example of both good and bad active sensors from an E39 BMW.

good

[IMG]

[/IMG]

faulty.

[IMG]

[/IMG]

Re: active abs tool

Posted by Lee Mackintosh User icon on February 22, 2011, 9:21 pm, in reply to "Re: active abs tool"
Lee Mackintosh

Also i always thought you couldn't measure an active type abs sensor with an ohmeter as you can cause damage to the sensor.

I did have a link on my old computer that explained these active sensors and how to test but can't find it now.

Re: active abs tool

Posted by Mark Carter User icon on February 22, 2011, 9:39 pm, in reply to "Re: active abs tool"
Mark Carter

Hi lee,
You are right, thats why we are talking about using a scope.

Regards mark

Modern cars, Its all wizardry and witchcraft

Re: active abs tool

Posted by Jon Morgan User icon on February 22, 2011, 11:39 pm, in reply to "Re: active abs tool"
Jonathan Morgan

We have just invested in a Pico - following this thread has inspired some questions.
Mark, the patterns Alan has posted show a difference in amplitude between the good & bad sensors - the bad showing half the amplitude of the good sensor.
Although I understand an analogue sensor will show an increase in amplitude depending on an increase in wheel speed, (which the digital sensor won't) - Alans faulty sensor is showing a 50% decrease in amplitude compared with the good.
Is this a typical example of a failed sensor - i.e a reduction in amplitude.
The bad sensor has also shown an increase in frequency x 4, is this another indication of a typical sensor failure & if so, why does it behave in this manner?.

On a learning curve,
Jon.

Re: active abs tool

Posted by Alan Kane User icon on February 23, 2011, 8:05 am, in reply to "Re: active abs tool"
Alan Kane - Administrator

Jon,

The frequency will increase with wheel speed under normal fault free operation. It is frequency that the ECU uses to calculate the wheel speed. When testing in the workshop. Unless you have the ability to drive the wheels at the same speed then the frequency will always be different.

The amplitude being low on the bad sensor was because the sensor was faulty but could also be caused by the air gap being wrong. The amplitude was low enough that the ECU was not seeing any signal.

I wouldn’t say that’s a typical failure. Missing switch points due to damage or open circuit (total failure) would probably be more common.

Just to give it some context, the bad sensor was a new GSF cheapie special. The garage faulted the old sensor based on a code read alone. Fitted the GSF one, then fitted a module which they asked me to code then asked me to look further when the module didn’t fix the fault. A new genuine sensor fixed it.

Re: active abs tool

Posted by Tom Williams User icon on February 23, 2011, 9:35 am, in reply to "Re: active abs tool"
Tom Williams

I haven't looked lately, but Bosch ESItronic used to have the wrong info for some vehicles. ie it gave inductive sensor 'scope patterns for some vehicles eg Volvo, which actually had active sensors.

Re: active abs tool

Posted by chris hogan User icon on February 24, 2011, 10:41 am, in reply to "Re: active abs tool"
Christopher Hogan

thanks for all the replies and scope patterns

chris

another day in school

Re: active abs tool

Posted by Lee Mackintosh User icon on February 24, 2011, 5:22 pm, in reply to "Re: active abs tool"

http://www.myzroadster.com/Files/tsbs/02_Tsbs/NTB02-120.pdf http://www.asashop.org/autoinc/aug2001/mech.htmHere is a link which i think describes the active type abs sensors.

there a 2 links bunched together for some reason

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