Air bag problem 42 light blinking 4-2 HELP!
 

My 03 expedition has a blinking air bag light. It blinks 4 times and then 2 times and repeats. I have googled this and found 42 = Primary Crash Sensor #2 Feed/Return Circuit - Open
Can someone tell me how to fix this? Where to look, what to test, what the service manual says???
Thanks

B2296 42 Restraint System — Impact Sensor Status (Front Impact Severity Sensor Circuit Fault)

The code 42 you are getting is called a LFC or Lamp Fault Code. This is a general code showing the area of the problem. To narrow down the problem, you have to go to a dealer who has a scanner and can read DTC faults. This will tell them if the fault is in the sensor or if it has a communication fault (wiring or plugs).

If we assume it's a communication problem, this is where the manual says to start;

J2 INSPECT THE FIRST ROW DRIVER SIDE IMPACT SENSOR MOUNTING, AND MOUNTING SURFACE
WARNING: If the supplemental restraint system (SRS) is being serviced, the system must be deactivated and restraint system diagnostic tools must be installed. Refer to Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) in this section.

The air bag restraint system diagnostic tools must be removed and the air bag modules reconnected when the system is reactivated to avoid non-deployment in a collision, resulting in possible personal injury. WARNING: Do not handle, move or change the original horizontal mounting position of the restraints control module (RCM) while the RCM is connected and the ignition switch is ON. Failure to follow these instructions may result in the inadvertent deployment of the safety canopy and risk of personal injury. WARNING: Never probe the connectors on the air bag module. Doing so can result in air bag deployment, which can result in personal injury. WARNING: The safety belt pretensioner is a pyrotechnic device. Always wear safety glasses when repairing an air bag equipped vehicle and when handling a safety belt buckle pretensioner or safety belt retractor pretensioner. Never probe a pretensioner electrical connector. Doing so could result in pretensioner or air bag deployment and could result in personal injury. WARNING: Never probe the electrical connector on a safety canopy module. Doing so can result in safety canopy deployment. NOTE: Diagnostics or repairs are not to be performed on a seat equipped with a seat side air bag with the seat in the vehicle. Prior to attempting to diagnose or repair a seat concern when equipped with a seat side air bag, the seat must be removed from the vehicle and the restraint system diagnostic tools must be installed in the seat side air bag electrical connectors. The restraint system diagnostic tools must be removed prior to operating the vehicle over the road. NOTE: After diagnosing or repairing an SRS, the restraint system diagnostic tools must be removed before operating the vehicle over the road. NOTE: After diagnosing or repairing a seat system, the restraint system diagnostic tools must be removed before operating the vehicle over the road. NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
Key in OFF position.
Deactivate the system. Refer to Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) in the Diagnosis and Testing portion of this section.
Access the first row driver side impact sensor located behind the front door trim panel. For additional information, refer to Side Impact Sensor—Front Row in this section.
Inspect the first row driver side impact sensor for:
loose electrical connector and ground wire.
damaged J-clip.
loose sensor mounting bolt.


CAUTION: The ground wire must be placed between the bolt head and the sensor. Never position the ground wire between the J-clip retaining nut and the sensor.
CAUTION: Always replace the J-clip retaining nut whenever installing a side impact sensor.
Remove the first row driver side impact sensor.
Visually inspect the first row driver side impact sensor, alignment tabs, electrical connectors, J-clip and mounting surface for damage, corrosion or dirt.

Was a significant amount of corrosion or dirt found, or was the first row driver side impact sensor attached to the mounting surface incorrectly or was the impact sensor bolt not fully seated and tightened correctly?
Yes
CLEAN and TIGHTEN the bolt. REPAIR the mounting surface as necessary. REINSTALL the first row driver side impact sensor. GO to J54 .

No
GO to J3 .
J3 INSTALL THE FIRST ROW DRIVER SIDE IMPACT SENSOR AND CARRY OUT THE ON-DEMAND SELF TEST

Mine has 26,000 miles and is less than 4 yrs old. Chances are it is a communications problem right? Dealers charge quite a bit just to scan codes right?
Should I buy one of those service manuals on dvd on ebay? This paragraph doesn't tell me where the sensors and connections are that I need to check nor does it tell me how to deactivate the system.
A newbie looking for a little more direction....thanks

The DVD/CDs sold on ebay are copies of the factory service docs. They will have the exact procedures in them that a dealership technician will have at hand. However, you will be without the benefit of the proper tools, training, experience, and tech support so your ability to properly and safely diagnose and repair this safety system will not be on par with a qualified dealership technician.

Procede at your own risk, only after having done research to be fully informed.

Steve

Access; the first row driver side impact sensor located behind the front door trim panel.

I find myself agreeing with Steve in the previous post. I have never worked on an airbag system myself, and looking at the above info, it doesn't look simple. If you read the whole paragraph(sorry it's all bunched together, the site was terribly slow last night) you will see you need to be careful when messing around with this system, or you will set it off. So they recommend you disconnect parts of the system to be safe. But when you do that, then you create more error codes that can interfere with your original trouble shooting, so they have all these special dummy loads and plugs to fake the system out.

I do not know if you can get the proper scanner to read the codes.

I know nobody likes going to the dealer. But that's the way it seems to end up on the newer trucks. They have made it so complex, that it's your only choice most of the time. I know lots of local repair shops that are having the same problem. They can't work on any of the newer vehicles without lots of expensive equipment and training.

There are some organizations that are recognizing the fact that this lock on info for the new cars may be on purpose, and are trying to change it. But the new car companies do invest a lot of money in their designs, and want to protect their investment.

My 04 Explorer just started doing the 4-2 code. I REALLY hope it is not this hard to fix. My husband and I have already had to do the "home" blend door fix from a YouTube video to avoid spending 1200.
Please tell me if there is anything easier (besides a Ford garage) to check this code.
Also: if we do nothing it means no airbag deployment, right?
Thanks

If you boil it all down, the problem is the front driver's side impact sensor. You may be able to do a visual check and spot something, but the rest of the above story is about how you can monkey around with this system and accidentally set it off. So proceed with caution.