BACKGROUND

​I have a 2005 Toyota Tacoma TRD Sport V6 4dr short bed, now with 107k mi.  Always garage-kept when not driving. Several years ago at around 65k mi, my airbag light began to periodically come on then go off. The frequency increased over the next month or so to the point where the airbag light simply stayed on.  I’ll save you the suspense and tell you the issue for me was the driver’s side front crash sensor, a common problem as reported by Scottie Kilmer on his YouTube Channel.

When I first noticed the problem, I checked all yellow SRS connectors on the crash sensors as well as under the seats. I also replaced the clockspring (no, my truck's VIN was not included in the recall). None of these efforts resolved the issue. There is a way to pull the SRS (airbag) fault codes on the 2nd gen Tacoma’s (2005-x) without a test tool.  Here’s how:

SRS FAULT CODE TEST PROCEDURE

- Turn the key to the ON position (do not start) and wait for 30 seconds,

- then using a paperclip, jump the TC and CG pins on the OBD2 connector located under the steering column.

- The dash airbag light will blink in a Morse Code like pattern, displaying the SRS fault code

(example: blink - short pause - blink - blink - blink - blink - long pause… (pattern repeated) would indicate fault code 14).

An SRS Fault Code=14 indicates the driver's side crash sensor fault (the code I was getting).  Code=13 indicates a passenger side crash sensor fault.  Note, these codes could also indicate a different problem like a cut wire.

To verify if it is indeed a faulty crash sensor,

• follow the CRASH SENSOR REPLACEMENT PROCESS below, and
• swap the two front crash sensors and note the SRS fault code again.  If the code changes from 14 to 13 (or vise versa), you likely have a front crash sensor failure.  As a precaution, when retesting the SRS fault codes, enter the vehicle from the passenger side and reach from the passenger seat to turn ON the ignition key.  This keeps you out of harms way in the unlikely event of an airbag deployment.

TESTING THE CRASH SENSOR / WHY DID IT FAIL?

The resistance of both front crash sensors were measured and both read approximately 1180 ohms. I learned ohms are not a good test for these TRW crash sensors and an oscilloscope is needed to perform a proper test.  So, I relied on the SRS fault code=14 that I was getting (and swapped the two as verification by a fault code=13).  I also disassembled the faulty crash sensor out of curiosity (see pics below).  What is interesting is that the crash sensor has no obvious mechanical components, only a circuit board that likely includes a miniature mechanical module.  Regardless, close inspection of the circuit board shows where the board shorted (arc’d), apparently a common problem with the original TRW part used on these vehicles.

CRASH SENSOR PART #

The front crash sensors made by TRW are interchangeable and use the same part #. The original Part # is: 89173-04010 has been prone to failure and has been replaced by Part #: 89173-09270 (order this one).  You are better off paying a few extra dollars and purchasing directly from Toyota (about $80 in 2016) instead of eBay or aftermarket.  If you can afford to buy two new crash sensors, that may be something to consider.  However, given how easy the procedure is and in my case, the passenger side crash sensor is still operating fine after 17 years, I would suggest only buying one unless you plan to keep the vehicle for an extended period of time. Note, the cost of the crash sensor in 2022 is now $120 and only likely to continue to rise.

CRASH SENSOR REPLACEMENT PROCESS

I did NOT disconnect the battery and had no issue (I've done this a few times now with no ill-effects). However, you should allow the vehicle to sit for at least one hour after turning off the ignition and removing the key before proceeding.  The one hour period will ensure there is no residual electrical energy within the SRS circuit. If you want to be extra safe, you can remove the battery negative terminal (just note that the sensor swap test mentioned above requires starting the vehicle). As for how to replace the faulty sensor(s):

-  Remove the grill (a 2 min job).  It has two 10mm bolts & two clips and the grill pulls straight up.  NOTE: the procedure can be done without pulling off the grill and using a long extension, but a 5 min job becomes a 2 hr job because you will struggle with limited access to the crash sensor yellow connectors, especially if you have large hands/forearms.

- With the grill off, use a flathead screwdriver with a fair amount of force to push the outer shell of the yellow connector straight back (wear gloves to avoid cutting your knuckles).

- Mark the sensors with P & D (Passenger / Driver side).

- Then, remove the two bolts and the crash sensor lifts straight up.

- Clean up any loose dirt/grease/debris in & around the connectors.

- If performing a Crash Sensor swap test (fault code 13/14), do it now*.

- Replace with the faulty sensor (connect the yellow connector before bolting down)*.

* Before reconnecting the yellow connector, be sure the vehicle is turned OFF for at least an hour with the key removed. Reason: you don’t want to simulate a crash while positioning the crash sensors through a sudden movement causing airbag deployment.  Also as a precaution, when retesting the SRS fault codes, enter the vehicle from the passenger side and reach from the passenger seat to turn ON the ignition key.  This keeps you out of harms way in the unlikely event of an airbag deployment.

If all goes as expected, your SRS airbag light will go off after starting your truck and waiting 20 seconds.  There is no need to reset any SRS codes since Toyota's SRS system performs a system test each time the vehicle is started.

Reinstall your grill and you should be good to go.