Airbag Problem

[marcop]

I have a 2001 Lincoln Towncar stretched limousine with an airbag problem that I can't find the cause.
When the ignition is switched on the airbag light flashes 3 times stops and then flashes 3 times again. It repeats this sequence about 4 times and then stays on permanently.
I've had a diagnostic code reader on it to try and find a specific fault, but this couldn't find any fault with the system.

Has anyone else had this sort of problem?

[Towncar]

OBDii won't read Airbag or ABS codes. You need the dealers readers for these two systems. That flash code means something.. lemme see if I have my 2001 manual handy....

[marcop]

It was the specialist dealer that was trying to read the code and reset the airbag light and it left them a little puzzled. It would be nice to know what the flashing sequence relates to.

[Towncar]

Restraints Control Module (RCM)

The restraints control module (RCM) is mounted on the center tunnel under the instrument panel. The RCM performs the following functions:

• signals the inflators to deploy the air bags in the event of a deployable crash.
• activates the safety belt retractor pretensioners to remove slack from the safety belt.
• monitors the air bag supplemental restraint system (SRS) for faults.
• illuminates the air bag indicator if a fault is detected.
• flashes the air bag indicator to indicate the lamp fault code (LFC) detected.
• communicates through the data link connector (DLC) the current or historical diagnostic trouble codes (DTCs).
• signals the instrument cluster to activate a chime if the air bag indicator is not available and another SRS fault exists.
• contains an internal safing sensor which is not serviced separately.

The RCM monitors the SRS for possible faults. If a fault is detected while the ignition switch is in the RUN position, the RCM will illuminate the air bag indicator located in the instrument cluster.

Here's what you need: Sounds like it's telling you Code 33 ??

When the ignition is cycled (turned off and then on), the air bag indicator will remain lit for six seconds and then go out. If an SRS fault exists, the air bag indicator will then flash the two-digit LFC. The air bag indicator will flash the LFC three times, then it will remain illuminated for the rest of the key cycle. The RCM will also communicate the current and historical DTCs through the data link connector (DLC), using the scan tool. If the air bag indicator does not function, and the system detects a fault condition, the RCM will signal the instrument cluster to activate an audible chime. The chime is a series of five sets of five tone bursts. If the chime is heard, the SRS and the air bag indicator require repair.

LFCs are prioritized. If two or more faults occur at the same time, the fault having the highest priority will be displayed first. After that fault has been corrected, the next highest priority fault will be displayed.

The RCM includes a backup power supply. This feature provides sufficient backup power to deploy the air bags in the event that the ignition circuit is damaged in a collision before the safing and air bag sensors determine that an air bag deployment is required. The backup power supply will deplete its stored energy approximately one minute after the battery ground cable is disconnected.


Electrical System

The electrical system that supports the air bag supplemental restraint system (SRS):

• is powered by the battery through the ignition circuit.
• provides the electrical path from the restraints control module (RCM) to the SRS components.
• provides the electrical path from the RCM to the air bag indicator.
• provides the electrical path from the RCM to the data link connector (DLC).
• provides the electrical path from the RCM to the instrument cluster.

[Towncar]

«2001 Town Car Table of Contents»
«Group 5: Body and Paint»
«Section 501-20B: OCCUPANT RESTRAINTS — PASSIVE — SUPPLEMENTAL AIR BAG SYSTEM»
«DIAGNOSIS AND TESTING»


Sounds like the seatbelt wires are disconnected


Pinpoint Tests — Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)


Pinpoint Test H: LFC 33 and 34/DTC B2292 — Restraint System - Safety Belt Pretensioner Status


Normal Operation

The restraints control module (RCM) checks all of the safety belt pretensioners for faults. If the RCM detects one of the following faults on any of the safety belt pretensioner circuits, it will store diagnostic trouble code (DTC) B2292 in memory and flash either lamp fault code (LFC) 33 or 34 depending on the fault (or higher priority code if one exists) on the air bag indicator.


Fault Conditions

The RCM monitors for the following fault conditions:

• Low resistance.
• Circuit open.
• Circuit short to battery.
• Circuit short to ground.

Possible Causes

A safety belt pretensioner status fault can be caused by:

• Wiring, terminals, or connectors.
• A faulty pretensioner.
• A faulty RCM.

Freakin Dealers, can't even read their own books

[marcop]

Thanks for that.
I'll check it out and see what i can find.

[reekor]

Says who? On the 2001 Town Car you can read all kinds of things via OBDii port, along with Airbag and ABS codes.

Originally Posted by Towncar

OBDii won't read Airbag or ABS codes. You need the dealers readers for these two systems. That flash code means something.. lemme see if I have my 2001 manual handy....

[Towncar]

Originally Posted by reekor

Says who? On the 2001 Town Car you can read all kinds of things via OBDii port, along with Airbag and ABS codes.

OOPS, I meant to say "OBDii readers"... The CAN readers might, I don't have one. Yes, with the right equipment the communications network can be fully accessed. (or did I mention that )

Obviously the dope "specialist... " couldn't get that far though..

[reekor]

You can get into all of the with just a OBDii system it does not need to be "CAN". From model to model of car and tool your options of what can be done is different, but lincolns tend to have the most toys tied into their OBDii systems. Most people run out and spend $100 or so and get what they pay for. I have met many specialist in my time, these people just make me want to buy more tools just so that I dont need to deal with them. lol

Originally Posted by Towncar

OOPS, I meant to say "OBDii readers"... The CAN readers might, I don't have one. Yes, with the right equipment the communications network can be fully accessed. (or did I mention that )

Obviously the dope "specialist... " couldn't get that far though..

[marcop]

You were spot on.
As this is a Limousine the front passenger seat has been removed to comply with UK regulations and make it an 8 passenger vehicle. The seat belt on the passenger side has been linked out with a resistor but after removing the paneling on the drivers side I found the cable to the drivers seat belt was disconnected. After reconnection the airbag fault cleared.