69MustangCoupe393cid

Ok so I hit a pretty bad pot hole the other day and bottomed my car out. I think I have code 19 from the airbag light that came on now, which indicated my RCM went off and has to be replaced. Ford is telling me I cannot just get one from another car, since it has to be programmed with the vin and whatever else they do or my airbag system wont work properly. Is this a crock of crap? They want 900 bucks to fix this. Plus I bubbled a tire and should probably get an alignment now too and I don't have collision on this car so insurance won't cover it. Help.

JRad405

I don't know anything about this, but you could try calling another dealer and seeing what they say. Then you can figure out if it's bs or not.

BraMas

I have never done one in a Mustang but have done them in other cars and never had to do any ECM work at all to replace them. There is all kinds of them on ebay

69MustangCoupe393cid

Yeah he was saying you have to reflash something and reprogram them with my vin and some stupid crap. I told him I was good and would just drive w/o airbags. But I do want to fix it so before I go through all the trouble I was wondering if anyone has had this happen that can say for sure I would be ok with one from another car. Also does anyone know what years were the same or if av6 would work etc.

69MustangCoupe393cid

So I just looked on ebay and there are a few guys that rebuild/reset these things. Does anybody know how this is done? I'm wondering if I can rebuild or reset the one I have in the car now.

cliffyk

They are packing you full of "it".

Here's a link to the RCM replacement procedure. At the end you will see the need to "Prove out the system", that consists of turning the key on:



To do this properly (with the air bags disconnected "just in case") you need two Air Bag Simulator tools:



These can be purchased online for an absurd amount of money, or you can just connect a 2.3Ω resistor cross the harness end of the airbag's squib leads (2.3Ω is not a standard value, so use two 4.7Ω resistors in parallel to get 2.35Ω which is close enough).

These leads are Gray/White and Gray/Orange on the driver's side, and Light Blue/Orange and Pink/Black on the passenger's side. If you use 4.7Ω 1/4W resistors you can just place them side-by-side, twist the leads together, and solder them up--snip 'em off to 5/8" or so, bend 90° and plug them right into the harness (this is also what needs to be done to trick the RCM if you remove an airbag).

It is all easy to do if done correctly--however you may want to go to one or more body shops where they deal with these all the time and get a price from them...

BTW, code 19 means that the RCM's Crash Data Memory module is full--this should not normally happen, so make sure the module is securely mounted and none of the captive nuts are loose.

The RCM code 19 (and most RCM codes) cannot be reset according to Ford--however there are "backdoor" ways of doing it with the proper equipment.

69MustangCoupe393cid

Cliffy you're the man, I'll see what resistors I have, I have about 700 of them in my garage. The car bottomed out and with the aftermarket suspension and such just the tires hitting cause a bit of a jolt when I hit bumps, the car doesn't exactly rid like a caddy.

69MustangCoupe393cid

I'm not sure I understand what proving out the system is. I don't get any chimes or anything when I turn my key on. Just the flashing of the airbag light which than turns solid when it's done with its test. Does proving the system reset anything? Or am I supposed to pull the bags and put those fakes in and see if I get the same error (which would prove my bags are ok)?

cliffyk

It does not reset anything, it is just the standard test that happens every time you start the car--you will not hear any chime unless the "air bag indicator" (the light) is inoperative. The system fault is indicated by the light's staying on as you indicated above.

However as in your original post you indicated you observed LFC (Lamp Fault Code) 19, I would not expect the system to "prove out" (self test) until the RCM is replaced. (Note that the LFC only reports the most serious code, there may be others that will be indicated when the highest priority problem had been fixed.)

The purpose disconnecting the air bags and plugging the the resistors into the harness it to to make the RCM believe the airbags are connected--so that after you replace the RCM, and perform the prove out, they will not detonate if some serious fault remains (or has been created during the repair).

The squib that detonates the air bag has a resistance of 2.3Ω if it is intact and "ready to blow". The RCM passes a small current limited test signal (just a few ma, it takes 5+ amps to light up the squib) through the squib to detect this resistance, and confirm that the air bag is connected and ready to go.

By placing the resistors across the harness connectors the RCM believes the air bags are there and "good to blow" while doing the test--a bit safer than doing the test (after the repair) with live explosives.

If the RCM does try to detonate a bag the resistors in place they will just go "poof", that's why using 1/4W resistors is a good idea--two 4.7Ω 1/4W unit in parallel can handle 1/2W maximum power, if the RCM tries to apply 5.0A at 12.0V that will be 60W and the resistors will go "poof"--not enough to start a fire or anything, just a pop and bit of smoke (don't ask how I know)...

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It can be difficult to find the 4.7Ω resistors locally, but you can get them for next to nothing on eBay.

When soldered in parallel to make the 2.3Ω value they will look like this:



Reshape the twisted/soldered leads to fit the harness connector.

69MustangCoupe393cid

Cool, thanks Cliffy. Now I have to find an RCM with my number on it I suppose. No way I'm paying Ford $350 for a new RCM. I can find one used for probably 30 bucks or even less in a yard, provided they didn't drop the car off a fork lift or was in a wreck prior.