Looking at seats... - Page 14 - Toyota Yaris Forums

MGargano · 08-19-2009, 11:12 PM

Quote:

Originally Posted by CTScott

I am measuring between the center wire (which is the signal output) and a chassis ground. I am using a needle probe, which is a very thin, sharp probe. With the waterproof connector, I am sticking it into the rubber seal around the wire.

Ok, I'll definitely give this another try tomorrow. I don't have work so I should have plenty of time to mess around.

Out of curiosity, based on what you see so far, does it look possible to turn the airbag (and seat belt light/chime) on and off with a toggle switch? Or will we have to rig something using the OEM sensors?

CTScott · 08-19-2009, 11:22 PM

Quote:

Originally Posted by MGargano

Ok, I'll definitely give this another try tomorrow. I don't have work so I should have plenty of time to mess around.

Out of curiosity, based on what you see so far, does it look possible to turn the airbag (and seat belt light/chime) on and off with a toggle switch? Or will we have to rig something using the OEM sensors?

I'm not sure yet. Tomorrow morning I'll take a look at the signal output with an oscilloscope.

MGargano · 08-20-2009, 12:11 AM

I'm psyched. I have a feeling tomorrow's going to be a good day for this project.

1NZYaris1 · 08-20-2009, 01:59 AM

You Guy's deserve an award

, soon we can all install sports seats

MGargano · 08-20-2009, 11:57 AM

I have all four sensors clamped like this:

Airbag 'Off' light and seat belt lights are still lit. Also not reading any voltage on the center wire.

CTScott · 08-20-2009, 01:58 PM

OK. With ignition power off, try reading resistance between the center wire and either of the outside wires. That will verify if you're actually making a good connection to the wire. You should see 48K ohms between the center and either outside wire.

MGargano · 08-20-2009, 02:07 PM

Ok. Should I keep the sensor clamped for this exercise? And I assume I'm changing the setting on the multimeter from VDC to ohms?

CTScott · 08-20-2009, 02:12 PM

Correct on VDC to ohms. Clamping is fine - It won't have any effect on the readings.

MGargano · 08-20-2009, 02:22 PM

Which setting am I putting the multimeter to?

I got a reading each time (center to left and center to right) with the black lead on center and the red on either outside wire but I have a feeling I have the meter on the wrong setting.

CTScott · 08-20-2009, 02:26 PM

Put the meter on 200K (always go to the next highest above what you are trying to see).

MGargano · 08-20-2009, 02:45 PM

Ok, with the meter on 200k, black lead in the center, red on either outside wire, I got 4.4 both times. I tried a few times and the numbers kept bouncing around some, but the most consistent (when I held my hands steady) was 4.4.

CTScott · 08-20-2009, 03:07 PM

OK. So right now your SRS light is off, air bag off is lit, and passenger seat belt is lit?

Try disconnecting the battery for 2 minutes, reconnecting and then measuring the voltage on the center pin to ground. for a really solid ground you might want to pop the passenger kick panel and touch the black lead to the ground bolt there.

MGargano · 08-20-2009, 03:13 PM

Quote:

Originally Posted by CTScott

OK. So right now your SRS light is off, air bag off is lit, and passenger seat belt is lit?

No, sir. All three lights, including the SRS, are still lit.

CTScott · 08-20-2009, 03:18 PM

With the SRS, are you still seeing the DTC 32?

MGargano · 08-20-2009, 03:23 PM

I just checked it. I now have 32, 55, & 56 again.

CTScott · 08-20-2009, 03:30 PM

You might want to check your resistors. I had trouble with mine not making great contact. I ended up shoving mine in through the wire side so they would fit tighter.

MGargano · 08-20-2009, 03:31 PM

Quote:

Originally Posted by CTScott

You might want to check your resistors. I had trouble with mine not making great contact. I ended up shoving mine in through the wire side so they would fit tighter.

Ok, I'll try that. Then do the dreaded reset of the SRS ECU again?

CTScott · 08-20-2009, 03:32 PM

Here's what I've found with the oscilloscope - Every 100ms the sensors transmit a packet of data. The beginning of the packet is always the same and the latter part varies based on pressure on the sensor.

Here are two sequential data packets from the front right sensor:
FR - Weight - Period.JPG

Here is one packet with no weight on the sensor:
FR - No Weight.JPG

Here is one packet with enough weight on the sensor for the airbag light to be lit:
FR - Weight.JPG

Based on this I can easily build a module to simulate the sensors (and to switch between an empty and occupied seat).

08-20-2009, 01:59 AM	#238
1NZYaris1 View User's Garage Drives: Yaris Join Date: Oct 2008 Location: New Zealand Posts: 2,566	You Guy's deserve an award , soon we can all install sports seats __________________ http://www.microimageonline.com/forums/index.php

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08-20-2009, 12:11 AM	#237
MGargano Drives: 2009 Yaris Hatchback Join Date: Feb 2009 Location: NJ Posts: 792	I'm psyched. I have a feeling tomorrow's going to be a good day for this project.

08-20-2009, 11:57 AM	#239
MGargano Drives: 2009 Yaris Hatchback Join Date: Feb 2009 Location: NJ Posts: 792	I have all four sensors clamped like this: Airbag 'Off' light and seat belt lights are still lit. Also not reading any voltage on the center wire.

08-20-2009, 01:58 PM	#240
CTScott ULTIMATE View User's Garage Drives: 09 5dr LB, 2x 08 3dr LB Join Date: Oct 2008 Location: USA, CT Posts: 13,460	OK. With ignition power off, try reading resistance between the center wire and either of the outside wires. That will verify if you're actually making a good connection to the wire. You should see 48K ohms between the center and either outside wire.

08-20-2009, 02:07 PM	#241
MGargano Drives: 2009 Yaris Hatchback Join Date: Feb 2009 Location: NJ Posts: 792	Ok. Should I keep the sensor clamped for this exercise? And I assume I'm changing the setting on the multimeter from VDC to ohms?

08-20-2009, 02:12 PM	#242
CTScott ULTIMATE View User's Garage Drives: 09 5dr LB, 2x 08 3dr LB Join Date: Oct 2008 Location: USA, CT Posts: 13,460	Correct on VDC to ohms. Clamping is fine - It won't have any effect on the readings.

08-20-2009, 02:22 PM	#243
MGargano Drives: 2009 Yaris Hatchback Join Date: Feb 2009 Location: NJ Posts: 792	Which setting am I putting the multimeter to? I got a reading each time (center to left and center to right) with the black lead on center and the red on either outside wire but I have a feeling I have the meter on the wrong setting.

08-20-2009, 02:26 PM	#244
CTScott ULTIMATE View User's Garage Drives: 09 5dr LB, 2x 08 3dr LB Join Date: Oct 2008 Location: USA, CT Posts: 13,460	Put the meter on 200K (always go to the next highest above what you are trying to see).

08-20-2009, 02:45 PM	#245
MGargano Drives: 2009 Yaris Hatchback Join Date: Feb 2009 Location: NJ Posts: 792	Ok, with the meter on 200k, black lead in the center, red on either outside wire, I got 4.4 both times. I tried a few times and the numbers kept bouncing around some, but the most consistent (when I held my hands steady) was 4.4.

08-20-2009, 03:07 PM	#246
CTScott ULTIMATE View User's Garage Drives: 09 5dr LB, 2x 08 3dr LB Join Date: Oct 2008 Location: USA, CT Posts: 13,460	OK. So right now your SRS light is off, air bag off is lit, and passenger seat belt is lit? Try disconnecting the battery for 2 minutes, reconnecting and then measuring the voltage on the center pin to ground. for a really solid ground you might want to pop the passenger kick panel and touch the black lead to the ground bolt there.

08-20-2009, 03:18 PM	#248
CTScott ULTIMATE View User's Garage Drives: 09 5dr LB, 2x 08 3dr LB Join Date: Oct 2008 Location: USA, CT Posts: 13,460	With the SRS, are you still seeing the DTC 32?

08-20-2009, 03:23 PM	#249
MGargano Drives: 2009 Yaris Hatchback Join Date: Feb 2009 Location: NJ Posts: 792	I just checked it. I now have 32, 55, & 56 again.

08-20-2009, 03:30 PM	#250
CTScott ULTIMATE View User's Garage Drives: 09 5dr LB, 2x 08 3dr LB Join Date: Oct 2008 Location: USA, CT Posts: 13,460	You might want to check your resistors. I had trouble with mine not making great contact. I ended up shoving mine in through the wire side so they would fit tighter.

08-20-2009, 03:32 PM	#252
CTScott ULTIMATE View User's Garage Drives: 09 5dr LB, 2x 08 3dr LB Join Date: Oct 2008 Location: USA, CT Posts: 13,460	Here's what I've found with the oscilloscope - Every 100ms the sensors transmit a packet of data. The beginning of the packet is always the same and the latter part varies based on pressure on the sensor. Here are two sequential data packets from the front right sensor: FR - Weight - Period.JPG Here is one packet with no weight on the sensor: FR - No Weight.JPG Here is one packet with enough weight on the sensor for the airbag light to be lit: FR - Weight.JPG Based on this I can easily build a module to simulate the sensors (and to switch between an empty and occupied seat).