SRS Diagnostic Question (Ohms)

17726 Views 13 Replies 6 Participants Last post by BamZipPow, Oct 3, 2020

andersonmh

Discussion Starter · Apr 23, 2009 (Edited)

1994 T-100 SR5.
My air bag light is constantly on when the ignition is not in the Lock position. The code I pulled is an 11 (Something wrong). The FSM diagnostic steps are:
From the Center Sensor Connector:
1) Check resistance between +SR and -SR, +SL and -SL. It should be between ~760 and ~880 Ohms (It was).
2) Check resistance between +SR and body ground and +SL and body ground. The resistance should be 1M Ohms or higher.

I have an analog MM. The needle never moved. Is this a pass or fail? I don't know what a 1M Ohm is.

BTW, I tried to clear the SRS Code (something like switching Tc and Ab to ground every second (twice) and leaving Tc to ground (I can't remember the correct interfaces)), but the code wouldn't clear.

TIA

Edit: On #2, the needle never moved... The resistance was okay on #1.

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BamZipPow

· #2 · Apr 23, 2009

1M ohms is 1 mega ohms...1000k ohms...or 1,000,000 ohms...

Like in computer terms...1 megabyte...

Is this condition new or has it been that way since you acquired it?

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andersonmh

Discussion Starter · #3 · Apr 23, 2009

It is relatively recent. I've owned the truck for about 10 years.

Thanks for the electrical education.

Original question: Is this a pass or fail?

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BamZipPow

· #4 · Apr 24, 2009

andersonmh said:
It is relatively recent. I've owned the truck for about 10 years.

Thanks for the electrical education.

Original question: Is this a pass or fail?

You'll need to set yer meter to the proper setting in order to find out. I have a cheap $14 digital meter that autoranges fer me. Without truely knowing the value...not sure I could answer pass/fail...

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andersonmh

Discussion Starter · #5 · Apr 27, 2009

Can't clear SRS codes.

I borrowed a good MM (Fluke) and I have the proper resistance in my previous post. During my diagnostics, I had to remove the air bag and I picked up another code (14) telling me that I have an open circuit between the air bag squib and center sensor, which would be correct since I disconnected the circuit when I pulled the air bag and steering wheel off.

The original code (11) was caused by a corroded connector that was attached to the LH front sensor. It wasn't OEM, a two piece connector with a rusted machine screw that held both peices together.

I tried to clear both of the SRS codes following the FSM instructions; Ignition to ACC or ON, Negative battery reconnected, and switch Tc and Ab to ground every second (twice) and leaving Tc to ground on the final 5th step, but the SRS codes wouldn't clear. I tried this more than once. I don't have a "Toyota Hand-Held Tester" to see if that would clear the codes.

Does anyone have a special trick that they have used to clear the SRS codes? Maybe my Center Sensor is bad ($$$s).

TIA

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zigzagg321

· #6 · Apr 27, 2009

you can buy an OBDII scanner from Mac Tools for $50.

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robiewp

· #7 · Apr 27, 2009

zigzagg321 said:
you can buy an OBDII scanner from Mac Tools for $50.

This will do nothing for a pre-96 vehicle, and in most cases won't help you with the airbag (not remotely emissions) anyway.

Some CAN/OBDII scanners can do that stuff on more modern cars (check air bags, roll your windows down...), but none for $50.

If you have a 96 or newer vehicle, though, an inexpensive OBDII scanner is a great tool.

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zigzagg321

· #8 · Apr 27, 2009

robiewp said:
This will do nothing for a pre-96 vehicle, and in most cases won't help you with the airbag (not remotely emissions) anyway.

Some CAN/OBDII scanners can do that stuff on more modern cars (check air bags, roll your windows down...), but none for $50.

If you have a 96 or newer vehicle, though, an inexpensive OBDII scanner is a great tool.

right you are. I missed the year.

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BamZipPow

· #9 · Sep 26, 2009

andersonmh said:
I tried to clear both of the SRS codes following the FSM instructions; Ignition to ACC or ON, Negative battery reconnected, and switch Tc and Ab to ground every second (twice) and leaving Tc to ground on the final 5th step, but the SRS codes wouldn't clear. I tried this more than once. I don't have a "Toyota Hand-Held Tester" to see if that would clear the codes.

Does anyone have a special trick that they have used to clear the SRS codes? Maybe my Center Sensor is bad ($$).

TIA

Okay...I ended up tripping a SRS code on my 1998 T-100 SR5 2WD auto when I had to move the passenger side (right) airbag sensor cable while doing my stock air box mod.

After staring at it fer about a week...I decided to read the code and then reset it.

To read the code, I got about 8' of network cable and stripped back 1" from 2 wires. I located the Diagnostic port in the engine bay and plugged one wire into the 3rd column 1st row (E1), and the other wire into 5th column 2nd row (Tc).
Brought the unattached end of the cable into the cab of the truck.
Connected both wires together.
Turned the ignition to the ACC position.
Read the flashes...one...five.
Code 15..."Open in front air bag sensor circuit".
Turned the key back to the LOCK postion.

Disconnected the wires (no longer touching each other) and moved the 1st wire to the 4th column 1st row (AB).
Turned the key to the ACC position.
Wait at least 6 seconds.
Using the visor screw as a convenient ground point, I held the Tc wire to the screw fer 1 second.
Removed the Tc wire and immediately held the AB wire in place fer 1 second.
Removed the AB wire and immediately held the Tc wire in place fer 1 second.
Removed the Tc wire and immediately held the AB wire in place fer 1 second.
Removed the AB wire and immediately held the Tc wire in place until I saw the code reappear.
Removed the wire from touching the screw.
Turned the key to the LOCK position and leave it in that position fer at least 20 seconds or more.
Turned the key to the ACC position.
The airbag indicator should light fer about 6 seconds and then turn off. If it still stays on repeat the process above until you git it right.

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samtoyota

· #10 · May 23, 2010

I have a 1996 t100 with air bag light on most of the times, Autozone scanner cant read it, I went to a mechanic and he pulled the code it was 31.
he said it was the air bag sensor itself in the dashboard area.
does that sound right or...
Thank you guys.

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andersonmh

Discussion Starter · #11 · May 23, 2010

samtoyota said:
I have a 1996 t100 with air bag light on most of the times, Autozone scanner cant read it, I went to a mechanic and he pulled the code it was 31.
he said it was the air bag sensor itself in the dashboard area.
does that sound right or...
Thank you guys.

I would have thought that a '96 would have the standard OBD-II 16 pin scanner interface. Anyway, I looked up your scan code (31) in my 1994 service manual and it says "center airbag sensor". In my truck, that's the expensive box located behind the seat and under the jack and tire iron. If it is just a loose connection, follow Bam's instructions for clearing the code. Otherwise, I'm afraid that it's going to cost some $$$s to get it fixed.

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BamZipPow

· #12 · May 23, 2010

andersonmh said:
I would have thought that a '96 would have the standard OBD-II 16 pin scanner interface. Anyway, I looked up your scan code (31) in my 1994 service manual and it says "center airbag sensor". In my truck, that's the expensive box located behind the seat and under the jack and tire iron. If it is just a loose connection, follow Bam's instructions for clearing the code. Otherwise, I'm afraid that it's going to cost some $$ to get it fixed.

You can't pull the SRS codes from the OBDII port...it has to be done through the diagnostics port in the engine bay.

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David THE DOORS!

· #13 · Oct 3, 2020

BamZipPow said:
Okay...I ended up tripping a SRS code on my 1998 T-100 SR5 2WD auto when I had to move the passenger side (right) airbag sensor cable while doing my stock air box mod.

After staring at it fer about a week...I decided to read the code and then reset it.

To read the code, I got about 8' of network cable and stripped back 1" from 2 wires. I located the Diagnostic port in the engine bay and plugged one wire into the 3rd column 1st row (E1), and the other wire into 5th column 2nd row (Tc).
Brought the unattached end of the cable into the cab of the truck.
Connected both wires together.
Turned the ignition to the ACC position.
Read the flashes...one...five.
Code 15..."Open in front air bag sensor circuit".
Turned the key back to the LOCK postion.

Disconnected the wires (no longer touching each other) and moved the 1st wire to the 4th column 1st row (AB).
Turned the key to the ACC position.
Wait at least 6 seconds.
Using the visor screw as a convenient ground point, I held the Tc wire to the screw fer 1 second.
Removed the Tc wire and immediately held the AB wire in place fer 1 second.
Removed the AB wire and immediately held the Tc wire in place fer 1 second.
Removed the Tc wire and immediately held the AB wire in place fer 1 second.
Removed the AB wire and immediately held the Tc wire in place until I saw the code reappear.
Removed the wire from touching the screw.
Turned the key to the LOCK position and leave it in that position fer at least 20 seconds or more.
Turned the key to the ACC position.
The airbag indicator should light fer about 6 seconds and then turn off. If it still stays on repeat the process above until you git it right.

where do u get this kind of info?????will these steps wrk for my 96 T100 5vzfe 4wd?

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BamZipPow

· #14 · Oct 3, 2020

David THE DOORS! said:
where do u get this kind of info?????will these steps wrk for my 96 T100 5vzfe 4wd?

I got it from the factory service manual (FSM). It should work fine fer yer T-100.

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