So I've spent a bit of time looking at various manuals and schematics and learning what I could online, but I'm still missing some key info. My SRS light shows a fault with the passenger pretensioner. I've tried jumpering the two leads to see if the closed circuit would fool the module into thinking the pretensioner was still good, but no difference. When I get my digital meter tomorrow I'll do a resistance check of the pretensioner, but I'm not sure what to look for. There is a write up in this forum involving a much later s-type, but that one uses a pretensioner on the buckle end, not in the reel end.

As an ignitor circuit I would expect a very low resistance, and for the above mentioned newer style it's 2.2 ohms. But if that was the case my shorting out the leads (I tried both a wire and a 2.2 ohm resistor) should have cleared the fault, which it did not. I even tried erasing the ECU memory and trying again, no luck. It's possible the fault is elsewhere in the circuit, which is just a simple loop, but before I go deeper, does anyone know what resistance readings I should get across the pretensioner? Is there a way to visually spot that it has fired? I could check the readings on the good one but I'm a little wary to go mucking about with it, if someone has this info at hand.

The nomenclature is also confusing as my manual says the code refers to a fault with the REAR passenger pretensioner circuit (code 37), but it doesn't mean rear seat. It labels the circuits as front and back pretensioner when referring to the same seat. For example the driver's seat has a front and back pretensioner. My 2001 electrical diagram shows one passenger pretensioner with two wires. What could it mean by REAR passenger pretensioner circuit?

 

Shorting is wrong, surely.

 

Another safety issue that needs addressed now before you drive the vehicle again. See the dealer.

 

The module checks for continuity, short to ground, short to power. Going to the ignitor should appear as a closed circuit, at this point resistance unknown but I would be very surprised if it amounted to anything; the point of a piece of such wire is resistance is low so when you pass a current through it it gets hot enough to ignite the pyrotechnic material; in effect a short that starts the combustion process. Since no one seems to know the answer I'll measure the resistance across the good one and check that the leads to the pretensioner aren't shorted or open.

The only way I use the dealer if I can't do the work because of the need for a unique tool that isn't available. I've owned over 50 vehicles and never had to use a dealer except for warranty.

 

Here's a good video showing the testing process. As I suspected, 2.2 ohms resistance across the leads is what is normal. So likely the fault is further upline, as placing a 2.2ohm resistor across or shorting the module leads still showed the fault.

 

IIRC the module needs to be reset after tripping, have a look for posts from Bodyman he had problems with this.

 

Checked and the pretensioner is good. Resetting by shorting the battery power leads doesn't clear it so I'll need to use a code reader/clearer. Still, one more fault figured out.