Airbag Light Fault Sensor- Passenger System Error
 

Hello and Good Morning members.

VEHICLE: 2006 XK-8/ 4.2 Liter/ Automatic Transmission/ Cloth Top/ Low Mileage/ Black/ Always “Babied”

CHALLENGE: AIRBAG WARNING LIGHT – PASSENGER SEAT – SPURIOUS ACTIVATION – FULLY ADJUSTABLE DRIVERS AND PASSENGER SEATS

It’s been a while since I “contributed” to the Forum, so I must apologize for not being more active. My 2006 XK-8 automobile has been so reliable and care free, that I’ve just been enjoying it, driving it and loving it!

My 2006 XK-8 has very low mileage and has been exceptionally well maintained. Always “babied,” as I prefer to say!

Now a “nagging” issue has come up that I need your kind advice on, please.

The Airbag Warning Light has been activated on the instrument panel. At the same time, on the Passenger side dash panel, the warning light has gone out when that seat is unoccupied.

With your kind assistance, I’d like to troubleshoot/diagnose the “issue.” If I can fix this challenge myself, it would be a Godsend!

Of course I’ve read the excellent and extensive information provided by members (thank you for that!).

The code sequence on the instrument panel warning light is as follows:
1. With no one in the passenger seat . . . . on starting the automobile, after the automatic, full, initial system check, the warning light on the instrument panel comes on and turns off slowly, twice.

2. Then that warning light flashes more quickly, a total of six times.

3. I take form reading the Airbag Warning Light “topic threads,” that this means the code elicited is “2/6”

4. Then the instrument panel light continues to flash very slowly as the car is driven, constantly on, then off.

5. During the entire time, the passenger side dash panel light is constantly unlit (off) (again, when no one is occupying the passenger seat)

6. With a person occupying the passenger seat . . . the sequence is the same, it is identical.


In conducting my initial investigation, I noted a “strange” occurrence, which I think might be of some significance:
1. With the automobile running, and me sitting in the passenger seat (no one in the drivers seat), all is as noted above.

2. I next begin to exit the automobile, and as I am doing this, swiveling my legs out, but with my “derriere” and the right side of my body still putting pressure on only part of the seat bottom and right-side lateral bolster, the passenger-side warning light comes on! (this warning light behaviour is thus now the reverse of how it should be operating)

3. I then continue to sit in this position (with the light remaining on) and observe that the instrument panel warning light is still flashing in its regular (not normal) pattern of slowly turning on and off.

4. When I fully exit the automobile, removing my weight from the seat and side bolster, the passenger dash panel warning light then goes out, and the instrument panel light remains flashing slowly, as it always now does.


Does the above “seat of the pants” testing offer any clues as to what might be wrong with the Airbag system?

Overall, so far, I’ve checked all the wiring under both the drivers and passenger seat, and everything seems to be in order. I’ve also operated all of the controls on both the drivers and passenger seats, in order to see it the seat positions make any difference, and they did not.

I’m suspecting that one of the passenger seat pressure and/or weight sensors has “gone haywire.” This is just my “WAG,” but I’m putting it out there for consideration.

If my suspicion is correct, does this require the actual passenger seat to be dismantled to replace a sensor? Is that even feasible?


Any assistance would be greatly valued.

Thank You.

Avery (sunny Los Angeles, California)

I've moved your question from General Tech Help to XK8/XKR forum. This is the place to post technical questions about your model.

The passenger seat occupancy sensor is built into the seat base foam. It is no longer available from Jaguar but a few US suppliers list old stock at $3300!

Graham

Here's the extract from JTIS detailing how the Passenger Seat Occupancy Sensing works:


Front Passenger Seat Occupant Classification Sensing System

NOTE: The front passenger seat occupant classification sensing system does not contain any serviceable components.

Individual components of the front passenger seat occupant classification sensing system are not serviceable. The system must be replaced as a complete unit and due to its sophistication, each replacement system requires calibration, so to avoid the need to provide calibration equipment to each dealer, a pre-calibrated
service kit is available. The following components are combined and calibrated during manufacture to form the front passenger seat occupant classification sensing system:

• Front passenger seat cushion
• Silicone filled bladder
• Front passenger seat occupant classification sensor control module
• Front passenger seat occupant classification sensor

The front passenger seat occupant classification sensor control module is mounted under the passenger front seat. The silicone filled bladder is integrated into the seat cushion and the front passenger seat occupant classification sensor, which is attached to the bladder, is mounted under the seat.

The silicone filled bladder responds to weight changes on the passenger front seat. The front passenger seat occupant classification sensor responds to these pressure changes and provides an appropriate signal to the front passenger seat occupant classification sensor control module. The front passenger seat occupant classification sensor control module processes the input signal received from the front passenger seat occupant classification sensor and makes it available to the RCM via the controller area network (CAN). In addition, the front passenger seat occupant classification sensor control module performs self-diagnostic functions on the system, with any malfunctions being notified to the RCM accordingly.

The front passenger seat occupant classification sensing system responds to the occupancy of the passenger front seat in accordance with the following:

• Passenger front seat status 'EMPTY' — Passenger air bag module status 'OFF' — Passenger air bag deactivation (PAD) indicator indicator 'OFF'
• Passenger front seat status 'OCCUPIED' (small occupant) — Passenger air bag status 'OFF' — PAD indicator 'ON'
• Passenger front seat status 'OCCUPIED' (large occupant) — Passenger air bag status 'ON' — PAD indicator 'OFF'

The SRS via the RCM, monitors and processes data from the front passenger seat occupant classification sensing system and several other sensors before making a deployment decision. Malfunction of the front passenger seat occupant classification sensing system or associated circuits will cause the SRS indicator to illuminate.

Your fault could be:

1. harness
2. bladder
3. occupant classification sensor
4. sensor control module

Worrying that the official Jaguar repair is simply to replace the lot to avoid recalibration issues.

Graham

Avery - welcome back to the forum. Glad to hear your car has been so reliable, mine too albeit "babied!"

GGG's market price of GBP3,300 is a bit of a shocker (UK price), but it does seem to be a sophisticated bit of kit. As it's a "nagging" issue rather then a deteriorating situation, or an urgent repair..... so can you live with it?

If not, first guess would be to try to find a second hand unit, maybe from a US breaker, or even get one off a scrap yard, hopefully from an uncrushed car. There is a new Marketplace on this Forum (see menu bar on top of page) where some cars are being "parted out."

Even if you go through the DIY route, you'll have to rip into the seat cushion, and probably getting the right parts for the repair will be difficult esp. as GGG said it's sold as a pre-calibrated sealed unit. You run the risk of ruining your passenger seat in the process.

My mistake.

It should have been $3,300. Out of habit, I'd hit the UKP key instead of the USD. Now corrected.

Graham

USD3,300 is still a bit of a shocker!