SRS Warning Light on, no DTC

Hi all,

I've had a 1993 Hiace SC LTD 4wd for about 10 months now, and the airbag light used to be intermittently on when first started, then went out.

Now it stays on. Failed my WoF inspection because of it.

So far the diagnostics I've done are:
- Check for a DTC shorting E1 and Tc, no DTC or normal code output
- Attempt to reset DTC (there wasn't one, so surprise surprise- didn't work)
- Check E1 and Tc for -ve and +ve respectively - OK
- Check for ACC + ON at the sensor assembly (with airbag removed and plug d/c) - OK
- Wiggle stuff and hope for the best - didn't work

My next thoughts are the SRS warning light circuit itself, or the voltage drop circuit have a fault... any ideas from some sparkies out there?

Thanks

locate sensor behind bumper, remove and treat with electrical contact cleaner

willyw wrote:

locate sensor behind bumper, remove and treat with electrical contact cleaner

Make sure you deal with the sensor switch with the ignition off or battery disconnected- otherwise you could trigger an airbag deployment.

If all else fails… remove the bulb from the dash warning light and fit a steering wheel from a non-airbag Toyota. (All Toyota wheels are interchangeable. I currently have a leather wheel from a RAV4 in my Super GL.)
The only question is whether the cause of wof failure was entered into the system.

willyw wrote:

locate sensor behind bumper, remove and treat with electrical contact cleaner

Unlikely to be that, if it was a connection issue there you would receive an open circuit code at the module.

I disassembled the Sensor Module, and found a leaking 220uF 10V capacitor. Replaced it with a new one (correct replacement, correct polarity), no dice. We also tried to reflow the chip right next to it which had some corroded pins.

Pretty sure the Sensor Module is faulty. Found a used replacement for $500 that comes with a 3 month guarantee, but I might try some part yards..

@Pete_nz - yep that would be a last resort and I'd check with my garage to see what they entered... ideally I want it fixed and working.