My van is spouting SRS fault codes 1-3 and 5-1. I had my shop run a diagnosis and it appears the module has failed. I'm having trouble tracking down a replacement. The Module on my van is Ford# F5AF-14BO56-AA. I see modules with -AD or -BD, but none that match this number perfectly. I also see lots of modules for related Ford vehicles from the same era. Does anyone have a ford parts numebr reference sheet that will indicate on what vehicles this module was used or if there is any chance that related modules are compatable?

TIA

-Mike

 

look for an air bag crash sensor short to ground and a blown thermal fuse...short in clock spring will also cause blown termal fuse....intermittent short must be repaired before new module or another blown thermal fuse

was the service done by a Ford shop?
the Air Bag module is a Ford dealer part only
or try here for used click

From Ford service cd
CODE 13


Fault Code 13


Air Bag or Crash Sensor Circuit Short to Ground


Circuit Description


Normal Operation

The diagnostic monitor measures the voltage at pin 11 (Circuit 614 GY/O) of the diagnostic monitor connector. The voltage at pin 11 varies with charging system voltage (the expected voltage at pin 11 is shown in the chart below)
Note that Circuit 614 is connected to Circuit 615 (GY/W) through the driver side air bag. Also, note that Circuit 615 is connected to the primary crash sensor feed Circuits (617 [PK/O] and 619 [PK/W]) through a diode inside the diagnostic monitor. If the diagnostic monitor measures a voltage of 2.0 volts or less at pin 11, the monitor will flash out code 13 to indicate a possible short to ground on this circuit (see possible causes below for additional circuits that may be shorted to ground). When flashing code 13, the diagnostic monitor blows its internal thermal fuse. This disables the air bag deployment circuit. If the short to ground is corrected, the voltage at pin 11 will return to normal and a fault code 51 will flash, indicating an open thermal fuse (see «Fault Code 51» for details).

NOTE:
Fault code 13 will flash only while the short to ground is present.


Possible Causes

Low voltage at diagnostic monitor pin 11 can be caused by:

1. A short to ground within the wiring harness on Circuits 614 (GY/O), 615 (GY/W), 623 (P/W), 617 (PK/O) or 619 (PK/W) causing the diagnostic voltage to drop.

2. An internal short to ground within the clockspring assembly causing the driver side air bag circuit(s) to be shorted to ground.

3. An internal short to ground within the safing sensor causing Circuit 614 (GY/O) or 623 (P/W) to be shorted to ground.

4. An internal short to ground within one or more of the crash sensors causing Circuits 617 (PK/O) and 619 (PK/W) to be shorted to ground.

5. An internal short to case ground within the driver side air bag.

NOTE:
Circuits 617 (PK/O) and 619 (PK/W) are all connected together inside the diagnostic monitor. Therefore, a short to ground on any of these circuits will short all of the circuits to ground.

Code 51
Pinpoint Tests


Air Bag Diagnostic Monitor Internal Thermal Fuse -- Fuse Blown Due to Intermittent Short to Ground


Normal Operation

Note:
The air bag diagnostic monitor contains an internal thermal fuse that is not serviceable. The thermal fuse is controlled by a computer inside the air bag diagnostic monitor. The computer will blow the thermal fuse whenever a short on the deployment circuits occurs. The thermal fuse does not blow because of excessive current flowing through it. DO NOT attempt to jumper out the thermal fuse with a circuit breaker or any other type of fuse.

Note:
DO NOT install a new air bag diagnostic monitor until the short has been located and corrected. If a short to ground has not been located and corrected, then the short to ground is intermittent and IS NOT PRESENT AT THIS TIME. Installing a new air bag diagnostic monitor with an intermittent short in the system will result in blown air bag diagnostic monitors and repeat repairs.

The air bag diagnostic monitor measures the voltages at the diagnostic monitor connector pins. When certain air bag deployment wires are shorted to ground (heavy lines illustrated in the schematic below), the supplemental air bag restraint system may become susceptible to unwanted deployment of the air bag(s). The air bag diagnostic monitor senses a short to ground on any of these circuits and helps prevent unwanted air bag deployant by blowing the diagnostic monitor thermal fuse. Blowing this fuse removes all power (battery and back-up power) from the air bag deployment circuits. While the short to ground exists, the monitor will flash code 13. If the short to ground is intermittent and temporarily corrects itself, the air bag diagnostic monitor will flash code 51.

Note:
If the short to ground returns, the high priority code 13 will flash instead of 51.

If the air bag indicator is flashing code 51 and a short to ground has not been serviced, this means that an intermittent short to ground exists in the supplemental air bag restraint system. The air bag diagnostic monitor should be replaced only after repairs to the intermittent short have been completed.

Some service tips for finding an intermittent short to ground are:

(1) Consult OASIS (Restraint Systems Service Code 104000) for up-to-date diagnostics and descriptions of wiring concern locations for the vehicle (VIN number) you are working on. OASIS is updated daily using concern descriptions from engineering and Dealership Service sources.

(2) Inspect wiring and harness in areas where they pass through or are located next to metal components (i.e., engine compartment bulkhead, body sheet metal, component mounting brackets, etc.).


Code 51 After Air Bag Deployment

Occasionally, immediately after an air bag deploys, the internal wiring of the driver side air bag module may become shorted to the metal housing of the driver side air bag module. This internal driver side air bag module short in driver side air bag module is detected by the air bag diagnostic monitor as short to ground in the air bag deployment wiring. Since the air bag diagnostic monitor is still operating immediately after most deployments, the monitor will detect the shorted wiring and will flash code 13 and blow the internal thermal fuse. After the deployment, as the air bag cools off, the internal shorted wiring may correct itself, therefore the short to ground will no longer exist and the air bag diagnostic monitor will flash code 51. If a vehicle with a deployed air bag is flashing code 51, inspect and replace all the damaged areas of the vehicle with crushed wiring, sensors, etc. If no damage is found, assume that the deployed air bag was the cause for the intermittent short and replace the air bag diagnostic monitor when the new driver side air bag module is installed.

Note:
Air bag diagnostic monitors can withstand several air bag deployments and do not need to be replaced after every deployment. Only replace the air bag diagnostic monitor if it is damaged.


Code 51 Sequence of Events

1. Short to ground occurs on one or more of the circuits shown in heavy lines in the schematic.

2. The air bag diagnostic monitor recognizes the shorted wiring and flashes out a diagnostic trouble code 13 and sends a signal to the internal thermal fuse, causing it to blow.

3. The air bag diagnostic monitor will continue to flash code 13 while the short to ground is present. If the short to ground goes away, a diagnostic trouble code 51 appears.

4. The air bag diagnostic monitor only flashes a code 51 when the thermal fuse is blown and the short to ground is not present. Do not replace the air bag diagnostic monitor until the short to ground has been located and serviced. Consult OASIS for shorted wiring information.


Air Bag Diagnostic Monitor Internal Fuse Blown and Short to Ground No Longer Exists

 

Excellent reply! I had the diagnosis performed by my independent. He took it as far as he could and then outsourced it to a technician/trainer with the essential instumentation. All diagnosis ended at the module itself. If I understand the service report, the short to ground can indeed be in the module and be intermittent. That makes alot of sense given the flip-flop of the fault code from 1-3 to 5-1 and back again. Given that no grounding shorts have been found external to the module, I guess I'll try a $50+ swap if I can locate the correct module and see how that goes.

Thanks again for the on-target, detailed feedback!

 

Mike:

That code 51 is definitely a blown thermal fuse. I replaced the fuse on mine a few years ago, and that took care of the problem. It hasn't come back either.

The fuse is pretty cheap and very easy to replace.

 

Copper,

I'd love to read how you did the fuse swap. where'd ya get the replacement fuse or what kind of fuse sis you use, if it's not obvious, where on the baord is the fuse located,, that sort of thing.

On my older bimmer, I've repaired overvoltage fuse for the SRS system no problem. For a few bucks I'd happily try it just to see if the short circuit blows it again.

However, here the issue needing to be addressed is what caused the thermal fuse to pop in the first place. The intermittant 1-3 is indicating a short is present, so as stated in the above Ford report, replacing the fuse will only result in it blowing again if there's a short. To that end I'm searching for a reasonably priced module.

 

Mike:

If you open up that Blue Airbag module, you'll see a small rectangular Black and White plastic box on the board (about 1" by 1/4"). Pry open that box and you will see a thermal fuse in parallel with a resistor. The thermal cutoff fuse is rated at 154 degree C if my memory is correct. You can buy one from a local electronic store for a few bucks. If you can't find it, PM me your address and I'll send one to you for free since I have one spare lying around somewhere when I did mine.

When the computer thinks a short has happened, it sends a current through the resistor to heat it up in order to blow the fuse deliberately.

You might have a short outside of the module and that will keep blowing the fuse. If that's the case, I'll suspect the clock spring. Before I replaced mine, 51 was only code I had, and it fixed the problem.

 

Thanks Tung,

Again excellent feedback from this forum. I've located a module and have it on the way. If as advised, my short is in the module, then that shoudl take care of it. If it blows, I know I'll be replacing the fuse as you've described here. Thanks for the generous offer, I should not have a problem locating one locally.

The clock spring was raised as a suspect early on. The diagnostics appeard to clear it, but I should get clarification from the guys with the tool to be sure.

-Mike

 

BCMike,
do you have any problems with cruise control or horn?
both of these switched circuits go thru the clockspring in steering wheel base
common for multiple clockspring circuits failures at same time

 

Well a quick happy follow-up. I picked up a replacement SRS module from a yard in WI, it seems to have done the trick. The SRS system checks when the ignition is turned on and after a couple seconds it's out again. Ahhh blissful dark idiot light panel again. Glad the diagnostics cost put me on the right target. Thanks again to all here, especially 96_4wdr, the info I got made everything perfectly clear.

So copper, I've got the module's fuse box open and am considering the fuse swap, I wonder if it could also have been the source of the short. I don't see any evidence of breaks or burns anywhere else on the board.

-Mike

 

My clock spring trashed itself and i replaced it but now have a 51 code. I checked the local radio hut stores and no one seems to have that fuse. any one know where i can buy one. that module is $250.00 .no way am i spending that for a fuse.

 

Im glade now I have a 94 and dont have to deal with any friggin OBD11 codes and flashing friggin lights gezzzzzzzzz. I got tried just reading that technical diagnosis stuff

 

read and listen before opening mouth click

from '93 Aero Ford Service cd
Supplemental Air Bag System
Diagnosing Customer Concerns Without Hard Fault Codes

If a fault code is reported by the customer but is not present when the car comes in for service, pinpoint diagnostics cannot be used. Following the pinpoint tests or fault tree diagnosis when the code is not flashing will result in needless replacement of the diagnostic monitor and repeat repairs. The diagnostic monitor does not contain any memory of the fault code after the key is turned off. If the fault code is unknown, instruct the customer on how to count a fault code. Demonstrate a fault code by disconnecting a primary crash sensor, turn the key to the ON position, and allow customer to count fault code. Reconnect the primary crash sensor and instruct customer to return when the code is known. Once the code is known, read the "Normal Operation" section for the fault code involved. Study the circuit diagram and determine the location of components that are involved in creating that fault code. Do a thorough visual inspection of components, connectors, splices and wiring harnesses, looking for pinched wires, worn insulation on conductors, opens, shorts, or loosely mounted sensors. The section "Possible Causes" lists the common concerns that relate to that particular fault code. Each concern is listed in the order that they are most likey to occur.

 

Gezzzzzzz all those flashing check engine lights will drive you crazy, I fixed mine by PUTTING A PIECE OF BLACK TAPE OVER THE DASH LIGHT,RUNS GREAT

 

Khan will love you for that. He sells catalytic converters

 

Hey, you are not supposed to advertize for me. I prefer to fix problems over masking them. BTW, catalyst efficiency codes indicate a problem elsewhere, and this problem likely causes poor performance and/or poor economy. Also, if the converter is removed or is not working, fuel consumption worsens on most if not all OBD-II and many OBD-I models. Has to do with fine tuneing and the effects of inadequate exhaust pressure, not to be confused with backpressure, which only occurs in true restriction.