Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Special Tool(s)
Material
Restraint System Diagnostic Tool Warning
WARNING: Restraint system diagnostic tools are for service only. Tools must be removed prior to operating the vehicle over the road. Failure to remove restraint system diagnostic tools could result in injury and possible violation of vehicle safety standards.
Diagnosing Customer Concerns Without Hard DTCs
If a lamp fault code (LFC) is reported by the customer but is not present when the vehicle comes in for service, follow the Diagnostic Instruction procedures in this section to identify the intermittent diagnostic trouble code (DTC).
Once the DTC is known, read the Normal Operation section of the pinpoint test for the DTC involved.
Follow the deactivation or depowering procedure as directed in this section.
Determine the location of components involved in creating the DTC.
Carry out a thorough visual inspection of:
components.
connectors.
splices and wiring harnesses.
insulation on conductors.
Refer to the Possible Causes section of the pinpoint test for the DTC involved, which lists the common concerns that relate to the DTC. Concerns are listed according to priority.
Diagnosing Customer Concerns with Hard DTCs
Most Supplemental Restraint System (SRS) diagnostic procedures will require deactivation and reactivation or depowering and repowering of the system. Deactivation and reactivation requires the disconnection of most SRS components and the installation of restraint system diagnostic tools. Depowering and repowering requires disconnecting of the battery and removal of the restraints control module (RCM) fuse. This reduces the risk of inadvertent deployment of SRS components while diagnostic procedures are being carried out.
Restraint system diagnostic tools are required for the diagnosis and testing of the SRS. It is not acceptable to short-circuit the air bag module connections with a jumper wire. If a jumper wire is used to short-circuit the air bag module connections, a lamp fault code (LFC) will be displayed.
Prove Out Procedure
Turn the ignition switch from the OFF to the ON position and visually monitor the air bag indicator with all SRS components connected or restraint system diagnostic tools installed. The air bag indicator will light continuously for approximately six seconds and then turn off. If an SRS fault is present, the air bag indicator will either:
fail to light.
remain lit continuously.
flash.
The flashing might not occur until approximately 30 seconds after the ignition switch has been turned from the OFF to the ON position. This is the time required for the restraints control module (RCM) to complete the testing of the SRS. If the air bag indicator is inoperative and an SRS fault exists, a chime will sound in a pattern of five sets of five beeps. If this occurs, the air bag indicator will need to be repaired before diagnosis can continue.
Glossary
Secondary Air Bag Warning Chime
The secondary air bag warning is an audible fault format that consists of five sets of five tone bursts, with each set of five tone bursts separated by a five second quiet period. One tone burst cycle will consist of one second ON and one second OFF. This series of five activations is repeated every 30 minutes.
Air Bag/Pretensioner Restraint System Diagnostic Tools
Air bag/pretensioner restraint system diagnostic tools are used to simulate the equivalent resistance of an air bag module or safety belt pretensioner during certain diagnostic procedures.
Disconnect the Component
Disconnect the component means to disconnect the component vehicle harness connector, not to remove the component. Do not reconnect a disconnected component unless instructed to do so.
Deactivate the System
Deactivate the system means to carry out a deactivation procedure. Service and Repair
Depower the System
Depower the system means to disconnect the battery and remove the restraints control module (RCM) fuse.
Prove Out the System
Prove out the system means to turn the ignition switch from the OFF to the ON position, and to visually monitor the air bag indicator with the air bag modules and safety belt pretensioners or restraint system diagnostic tools installed. Refer to Prove Out Procedure in this section.
Reactivate the System
Reactivate the system means to carry out the reactivation procedure. Service and Repair
Repower the System
Repower the system means to remove any restraint system diagnostic tools that may have been installed, turn the ignition ON, install the RCM fuse, and connect the battery ground cable.
Reconnect the System
Reconnect the system means to reconnect all system components. Refer to Air Bag System Reconnect Checklist in this section.
Install a New Component
Install a new component means to remove the existing component and install a new authorized part obtained from Ford Customer Service Division.
Verify the System
Verify the system means to prove out the system with restraint system diagnostic tools installed in place of the SRS components.
Air Bag Reconnect Checklist
The checklist below should be completed following diagnosis and repair of any air bag system concern:
1. Is the clockspring connector at the base of the steering column connected?
2. Are the air bag modules connected?
3. Are the safety belt retractor pretensioners connected?
4. Is the RCM connected?
5. Is the vehicle battery connected?
The Symptom Chart can be used to help locate the air bag SRS concerns if no DTCs are retrieved and the listed symptoms are observed. Whether or not the listed symptoms are observed, always carry out the following:
6. Retrieve all DTCs stored in the RCM memory. Go to the Retrieve/Clear Continuous DTCs in this section.
7. Carry out the On-Demand Self Test to determine what DTCs are currently being sensed by the RCM. Go to the On-Demand Self Test in this section.
8. If the stored DTCs are different than the current DTCs, always repair the current DTCs first.
A DTC can indicate several concerns. The DTCs are to assist in system diagnosis and are not to be considered definitive. Always refer to the pinpoint test corresponding to the DTC to determine where the concern lies and to repair the concern correctly.
The SRS diagnostics can be divided into three sections:
Diagnostic test modes
PID/data monitor and record
Active command modes
Lamp Fault Code (LFC)
When the RCM detects a fault, it will cause the air bag indicator to flash a coded sequence called a LFC. The code is one or two digits. The digit is indicated by a number of flashes with a 0.5 second interval between pulses for a two digit LFC. There is a 5 second pause between each display of an LFC.
Each LFC is flashed five times after which the air bag indicator will remain lit as long as the key remains in the RUN position. If there are multiple LFCs, each LFC will flash in order of priority.
Each LFC has one or more associated DTC.
Lamp Fault Code (LFC) No DTCs
This signifies the RCM has detected a deployment and at one time had a DTC B1231 that was cleared with a scan tool. The flash code 13 will not clear. Installation of a new RCM is required.