B1900 srs code

[yakovenkooleg]

have srs light on , DTC code 1900 (short in right seatbelt pretensioner) have done everything to it. changed seat belt, floor wire, srs modual, light is still on. any ideas why and what can cause that?

[CTScott]

Did you replace the seatbelt with a used one? If so, check the rectangular block on the end and if you can see orange through the tiny holes, then the replacement one popped in a crash.

[yakovenkooleg]

i replaced it with used one ( i've actually tried two different once) and they are good. you cant see the orange or red in the holes. i did take apart the one that went off in the accident, and you can clearly see the red stuff in the holes

[CTScott]

i replaced it with used one ( i've actually tried two different once) and they are good. you cant see the orange or red in the holes. i did take apart the one that went off in the accident, and you can clearly see the red stuff in the holes

OK. In that case, have you cleared the code with the procedure in the thread below, as that is a code that will not clear automatically.

http://www.yarisworld.com/forums/showthread.php?p=557473&posted=1#post557473

[yakovenkooleg]

yes i have! i do the procedure, after which when i turn off the ignition for less than a second the srs light functions normal, but when the ignition is off for more than a second the light remains on and the same code is up, which is 73

[CTScott]

yes i have! i do the procedure, after which when i turn off the ignition for less than a second the srs light functions normal, but when the ignition is off for more than a second the light remains on and the same code is up, which is 73

OK. So either the wiring between the SRS ECU and the seat belt is damaged or that output channel on the SRS ECU is bad. You mentioned that you checked everything out. How did you test the wires?

[yakovenkooleg]

I unbuckled both ends ( from srs ecu and seat belt) and ran voltage through each wire individually

[CTScott]

I unbuckled both ends ( from srs ecu and seat belt) and ran voltage through each wire individually

The B1900 code indicates a short, so if you have a multimeter, the best way to check it would be to disconnect both ends and measure the resistance between the two pins (it should measure as a open connection) and then each pin separately to chassis ground (which should also both measure as open connections). If that all checks out then you have a bad SRS ECU.

[yakovenkooleg]

What should be a resistance on that? A zero?

[CTScott]

What should be a resistance on that? A zero?

Zero would be a short. You should see the same thing on the display as you would see with the probes not touching anything (some meters display O.L. or something like that)

[yakovenkooleg]

So I just put probes to the negative and positive side if the seatbelt connector?

[CTScott]

So I just put probes to the negative and positive side if the seatbelt connector?

Yes first do that, then do each individually with the other probe on a chassis ground (any unpainted bolt into metal)

[yakovenkooleg]

Does the ignition has to be on while I do that?

[CTScott]

Does the ignition has to be on while I do that?

No. It must be off before you unplug the two ends.

[yakovenkooleg]

Checked it all out, looks good. Getting O L on the ohm meter on both wires and on the grounds!

[CTScott]

Checked it all out, looks good. Getting O L on the ohm meter on both wires and on the grounds!

OK. So it sounds like you need a new SRS ECU. What's the part number on the one in your car?

[yakovenkooleg]

80z0661331 i dont know if thats the right one. but i have two different SRS ECU, one that i had the crash data cleared off of, and the other one from my donor (parts car) that i have.
both of then show the same code. maybe i need one from a dealer, a brand new one?

[CTScott]

The part number should be 89170-52630 or 89170-52690 for your 08 3 door. If you PM me your VIN I can tell you specifically which one it should have.

I have a couple of good 89170-52690 on hand if that's what you need.

[yakovenkooleg]

replaced the SRS module. with a new one from dealer... didnt help at all... dont even know where to look for now!!!

[CTScott]

replaced the SRS module. with a new one from dealer... didnt help at all... dont even know where to look for now!!!

How are you reading the code (i.e. is it possible you have it wrong).

Since the SRS ECU is new, and the wiring tested fine, if that is the correct code, then the pretensioner has to be the culprit. Before buying another one, you can connect a 3 ohm (make sure it is 3, not 3K ohm) in place of the pretensioner to verify.

[yakovenkooleg]

getting a 2.3 ohms on a seat belt.... the thing is ive tried 3 different seat belt, i know they are all good for sure! tried 3 different modules, including one brand new one, still getting 7 and 3 blinks!

[CTScott]

getting a 2.3 ohms on a seat belt.... the thing is ive tried 3 different seat belt, i know they are all good for sure! tried 3 different modules, including one brand new one, still getting 7 and 3 blinks!

For the heck of it, check the connector under the driver's seat for the driver's seat belt buckle. That would be code "37".

[yakovenkooleg]

For the heck of it, check the connector under the driver's seat for the driver's seat belt buckle. That would be code "37".

Replaced the whole damn seat, tried different wheel airbag and a clock spring, nothing seems to work. This is crazy!

[CTScott]

Replaced the whole damn seat, tried different wheel airbag and a clock spring, nothing seems to work. This is crazy!

It definitely is crazy. Check that connector now though, as you never know.

[yakovenkooleg]

checked evrything! i even replaced the passanger airbag and passanger seat with seatbelt just in case.. i know dealer will be no help to me cuz they got the standard operation procidure, and i did it all my self. maybe somebody here had the same problem and they have the solution?

[CTScott]

checked evrything! i even replaced the passanger airbag and passanger seat with seatbelt just in case.. i know dealer will be no help to me cuz they got the standard operation procidure, and i did it all my self. maybe somebody here had the same problem and they have the solution?

The only thing left would be the actual wiring harness.

Can you take a video of the light pattern?

[yakovenkooleg]

The floor or the dash harness?

[CTScott]

The floor or the dash harness?

The floor one is the one that goes from the SRS ECU to the pretensioners. I really don't think that it is the harness though, with what I had you test.

I would really like to see the light pattern. If it would be easier for shooting it to me, I can PM you my cell or email to send it to. From there we can go through a step by step bit of testing to try to pinpoint the problem.

[Brett!]

I am on the edge of my seat. This is playing out like that Nicolas Cage movie National Treasure. I hope you find the answer, dude.

[yakovenkooleg]

here is the video! first i jump two pins to read the code (7 and 3 blinks) than i try to erase the code (two attempts) after which you can see when you turn the ignition off for about one second the light functions normal, but when its off for a little longer the light comes back on again with the same code!

http://www.youtube.com/watch?v=eA-asC2-C-s

[CTScott]

here is the video! first i jump two pins to read the code (7 and 3 blinks) than i try to erase the code (two attempts) after which you can see when you turn the ignition off for about one second the light functions normal, but when its off for a little longer the light comes back on again with the same code!

http://www.youtube.com/watch?v=eA-asC2-C-s

OK. I definitely agree that it is code 73, which the service manual says is "short in right hand pretensioner squib". What if that is a misprint, as 73 is short in left hand on many other Toyotas?

Have you perchance checked the driver's side one?

[yakovenkooleg]

thats the thing.. some service manual say its the right side some say its the left side, thats why i've tried both sides..right now i got the new floor wiring in it, new seats (both sides) new seat belts (both sides) new wheel bag, new passenger bag, new module, and a new front airbag sensors (both sides) the only thing i haven't replaced on that is the dash harness and the wires that go out to the front impact sensors. i am just clueless about this whole thing!

[CTScott]

thats the thing.. some service manual say its the right side some say its the left side, thats why i've tried both sides..right now i got the new floor wiring in it, new seats (both sides) new seat belts (both sides) new wheel bag, new passenger bag, new module, and a new front airbag sensors (both sides) the only thing i haven't replaced on that is the dash harness and the wires that go out to the front impact sensors. i am just clueless about this whole thing!

I can't believe that you've replaced all of that. I don't even want to know what you have spent thus far. Let me force a fault on the pretensioner on one of mine and verify that 73 is really correct (and for what side). I will do that this evening...

[yakovenkooleg]

i have a parts car so there is not much i spent so far except time and a new SRS ESU from dealer which was like 119$. it is a left (drivers side)

[CTScott]

i have a parts car so there is not much i spent so far except time and a new SRS ESU from dealer which was like 119$. it is a left (drivers side)

OK. I had a chance to try it now before I have to run out to meet with a client. Code 73 came up when I disconnected the left pretensioner, the right pretensioner and both. Code 74 never came up. So, that code 73 alone is not particularly helpful in figuring out which side is the issue.

When I get back I will put together a set of instructions for what to do next.

[CTScott]

Out of curiosity, did your parts car have one or both of the airbags pop?

[yakovenkooleg]

no. the parts car was hit in the back so no airbags or belts went off..the car ran fine and the light functioned normal before i took it apart. the builder that i am having issues with was hit in front and the drivers airbag poped and drivers seat belt went off too.

[yakovenkooleg]

the thing is tho..code 73 comes up for all for DTC codes ( B1900, B1901, B1902 and B1903) so if its an open circuit or a shorting in the circuit it will still be code 73 until u scan it with a scanner and pull out actual B code. at first when i fixed the car< i didn't know that the belt went off so i just replaced the drivers bag and went to the dealer to get the light shut off.. he told me that there is a cod B1901/73, which is a open in a circuit, so then i replaced the belt, the B1901 was cleared but B1900 is now appearing. i am just wondering back when i had the B1901 code, why did the computer showed only this code, but didnt show the B1900?

[CTScott]

the thing is tho..code 73 comes up for all for DTC codes ( B1900, B1901, B1902 and B1903) so if its an open circuit or a shorting in the circuit it will still be code 73 until u scan it with a scanner and pull out actual B code. at first when i fixed the car< i didn't know that the belt went off so i just replaced the drivers bag and went to the dealer to get the light shut off.. he told me that there is a cod B1901/73, which is a open in a circuit, so then i replaced the belt, the B1901 was cleared but B1900 is now appearing. i am just wondering back when i had the B1901 code, why did the computer showed only this code, but didnt show the B1900?

TechStream definitely helps for being able to differentiate the sub codes. I worked on a rebuilt Tundra for a friend of mine, where he was having a pretensioner issue and it still remained opened as a 73 after he replaced the seatbelt. I scanned it with my Techstream and the code was a 1900. We found that the insulation on the pretensioner wires melted a bit (a couple of inches from the connector) and then with him moving the cable to unplug and replug the pretensioner the wires moved to where the exposed copper of the two wires was making contact.

[yakovenkooleg]

Wires look good on mine!

[CTScott]

OK. I finally had a chance to snap some pics of what I want you to try with your meter. You will want to do this testing with the ignition off (and ideally with the negative battery terminal disconnected for safety). With the SRS ECU side there is a safety mechanism in the connector which shorts the two pins going to each squib together when the connector is unplugged, so you will do the testing with the SRS ECU connector plugged in and the Pretensioner connectors unplugged.

On the SRS ECU you are interested in the two sets of two wires that are circled here. The two on the right go to the left pretensioner and the two on the left go to the right prestensioner.
52581

If you probes are large, you will need a small piece of wire to stick into the pretensioner connector hole being tested:
52582

For both sides you will need to test the yellow wire and the yellow/black wire separately.

Here you can see that with no connection my meter shows "OL":
52583


1. First test from one end of the wire to the other and you should see close to zero ohms:
52584

2. Next test between the yellow and the yellow black wire and you should see a high resistance (in my case 3.75 M ohms):
52585

3. Next test between the yellow wire and ground and then between the yellow/black wire and ground and you should see a relatively high resistance (in my case 2865 Ohms):
52586


Try the above for each of the two wires on both sides.

[yakovenkooleg]

ok for the first step where i measured from one end to another on all 4 wires i was getting 00.2 ohms when my ohmmeter was set at 200
second step where i was measuring between yellow and yellow/black i was betting OL on all 4 wires. that's probably because my ohmmeter goes up only to 2M ohms.
third step where i would measure wires from seat-belt connector to the ground i was getting a 3.13 ohms on yellow wire only (for both sides) when my ohmmeter was set at 20K , but nothing for yellow/ black wire. just kept getting OL on all settings of the ohmmeter.

[CTScott]

ok for the first step where i measured from one end to another on all 4 wires i was getting 00.2 ohms when my ohmmeter was set at 200
second step where i was measuring between yellow and yellow/black i was betting OL on all 4 wires. that's probably because my ohmmeter goes up only to 2M ohms.
third step where i would measure wires from seat-belt connector to the ground i was getting a 3.13 ohms on yellow wire only (for both sides) when my ohmmeter was set at 20K , but nothing for yellow/ black wire. just kept getting OL on all settings of the ohmmeter.

OK. That is all correct. On the yellow/black to ground I see over 3 M Ohm where the yellow to ground is in the 3 K Ohm range.

Can you get your hands on two 3 ohm resistors (any wattage is fine)? I would like you to stick the 3 ohm resistor into the pretentsioner connector on both sides to see if bypassing the pretensioners makes a difference. I know you have tried multiple different pretensioners, but the resistors will give us an easy absolute test.

[yakovenkooleg]

would a 2.2 resistor do it?

[CTScott]

would a 2.2 resistor do it?

Yes 2.2 ohms would be fine.

[yakovenkooleg]

ok...narrowed it down a little bit. when i put a resistors in both connections it did the trick, the light went off without even clearing the code!! (good news) than i began doing them separately! hooked up a seat-belt right (passenger side) but left the resistor in the left side (drivers side) seat-belt connector, again, the light goes off! hooking up the left side (drivers) connector to a seat-belt, light remains on! what could that possibly be? seat-belt should be good because when i test that seat belt on the right (passenger) side it works, but doesn't work on the left (drivers side)

[CTScott]

ok...narrowed it down a little bit. when i put a resistors in both connections it did the trick, the light went off without even clearing the code!! (good news) than i began doing them separately! hooked up a seat-belt right (passenger side) but left the resistor in the left side (drivers side) seat-belt connector, again, the light goes off! hooking up the left side (drivers) connector to a seat-belt, light remains on! what could that possibly be? seat-belt should be good because when i test that seat belt on the right (passenger) side it works, but doesn't work on the left (drivers side)

That is very strange that it works on one side but not the other. It may be that the harness connector is damaged to where the resistor can make contact with the pretensioner pins, but the pt pins can not.

[yakovenkooleg]

it is strange, because when i measure the seat belt, i am getting 2.3 ohms of resistance on it, same as the resistor that i am using!

[Rodger Wilco]

Hey guys I have a similar code on my 2010 Yaris maybe you can help. The code reads: B1901 Open in P/T Squib(RH) Circuit.

Also, the diagnostic computer tester thing I used I had borrowed from a friend and it only had the option for a 2007-2009 Yaris, it did not have database for 2010, I am wondering how much of a difference that would make?

Where do I go from here besides a dealer? I am resolved to fix this thing without spending $$$ at the dealership.

Thanks!

[CTScott]

Hey guys I have a similar code on my 2010 Yaris maybe you can help. The code reads: B1901 Open in P/T Squib(RH) Circuit.

Also, the diagnostic computer tester thing I used I had borrowed from a friend and it only had the option for a 2007-2009 Yaris, it did not have database for 2010, I am wondering how much of a difference that would make?

Where do I go from here besides a dealer? I am resolved to fix this thing without spending $$$ at the dealership.

Thanks!

Was your Yaris in a crash? The B1901 code signifies that the driver's side squib is open (which typically means that it popped in a crash). You can verify that by pulling the B pillar lower cover and checking the rectangular block on the side of the seatbelt assembly. If you see orange through the little holes, then it did pop and will need to be replaced.

As far as the year part goes, 2006-2011 are identical as far as SRS codes go.

[Rodger Wilco]

Was your Yaris in a crash? The B1901 code signifies that the driver's side squib is open (which typically means that it popped in a crash). You can verify that by pulling the B pillar lower cover and checking the rectangular block on the side of the seatbelt assembly. If you see orange through the little holes, then it did pop and will need to be replaced.

As far as the year part goes, 2006-2011 are identical as far as SRS codes go.

Yes it was in a crash but a very minor one. Only the front bumper/crumple zone was damaged. That is why I got such a killer deal on it. I will pull the cover off and report what I find.

Thanks!