How to find out if a sensor is bad?

[black89targa]

Well i have had only a few problems with my Supra since i bought it but lately the mass air flow went bad, it took about 16 days for me to diagnose it. And not to be negative but searching this site really hasnt brought me any luck on geting this question answered.

so how do people check to see if a sensor is bad or not? checking the resistance? if so then how do you go about checking resistance in a sensor? this is usually a step after checking to see if any wires are loose or disconnected right? i think this would be a great thread in the tech/faq forum.

Nathan

 

[jdub]

Why don't you try reading what the TRSM has to say about a specific sensor

Just a thought...a real novel idea actually.

 

[Kckazdude]

I thought the title was a trick question.

The repair manuals are really specific on how to test the sensors.

 

[suprabad]

Although I've had sensors that checked out ok but had intermittent problems that didn't show up under the test parameters.

When in doubt...swap it out.

 

[ModularTurbo]

If you are running a oil charged intake filter it can affect you maf, electronics cleaner will take of it. This used to happen every year on my tacoma.

 

[black89targa]

Thanks guys i'll look into what the manuals say about it. is every sensor in the manual?

 

[Kckazdude]

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/default.aspx

All of them are covered in very good detail.

Although I've had sensors that checked out ok but had intermittent problems that didn't show up under the test parameters.

When in doubt...swap it out.

I will say I have certain known good items I will swap around for testing purposes, it isnt a practice I condone. There could be problems in the circuit as well that is creating the problem.

 

[jetjock]

If you are running a oil charged intake filter it can affect you maf, electronics cleaner will take of it. This used to happen every year on my tacoma.

^ It never ends.

Kck: It's a terrible practice. Monkeys can swap parts. As long as one is smarter than the sensor/circuit and knows how to check it properly there will never be doubt, especially on stuff this simple.

 

[Kckazdude]

^ It never ends.

Kck: It's a terrible practice. Monkeys can swap parts. As long as one is smarter than the sensor/circuit and knows how to check it properly there will never be doubt, especially on stuff this simple.

You know I agree with you 110%. I should have stated it was a practice I did on newer cars when I worked as a tech. There were 2 switches that were very common for failure. The PW and defrost switches. Sensors were always tested for malfunction.

 

[suprabad]

^ It never ends.

Kck: It's a terrible practice. Monkeys can swap parts. As long as one is smarter than the sensor/circuit and knows how to check it properly there will never be doubt, especially on stuff this simple.

It doesn't hurt anything to swap something out just to make sure...nor does it make you a monkey. As stated, it's not impossible to miss some parameter that might reveal a flaw in any given sensor.

Even the TSRM suggests swapping some electronics (ecm for example) with a known working unit.

 

[jetjock]

Imo it makes someone a poor diagnostician and all the truly competent ones I know would agree. Besides, we were talking about sensors and their circuits. Nothing even close to rocket science there, just first grade electronics. As for the TSRM it was written for the common denominator. In the end it's all relative...

 

[Nick M]

If you are running a oil charged intake filter it can affect you maf, electronics cleaner will take of it. This used to happen every year on my tacoma.

Your Tacoma does not use a Karman Vortex air flow meter like the Supra does. Spraying cleaner in there is bad for the mirror and LED.

 

[ModularTurbo]

Your Tacoma does not use a Karman Vortex air flow meter like the Supra does. Spraying cleaner in there is bad for the mirror and LED.

Whoops... same as the dsm's my bad. Thanks for keeping me straight. :icon_razz