There are tests that can be done to check the front Impact Sensor circuit, but you do have to be very confident of your test abilities using a good test meter. You always have to be aware that an error on your part or a slip with a test meter might set an airbag off!! I cannot take responsibility for any outcomes if you try this without success.

That said, if you want to proceed, this is the published Jaguar procedure (For FWD only):

TO AVOID ACCIDENTAL DEPLOYMENT AND POSSIBLE PERSONAL INJURY, THE BACKUP POWER SUPPLY MUST BE DEPLETED BEFORE REPAIRING OR REPLACING ANY AIR BAG SRS COMPONENTS. TO DEPLETE THE BACKUP POWER SUPPLY ENERGY, DISCONNECT THE BATTERY GROUND CABLE AND WAIT FOR ONE MINUTE. FAILURE TO FOLLOW THIS INSTRUCTION MAY RESULT IN PERSONAL INJURY.

Disconnect the battery negative terminal. Wait one minute for the backup power supply to deplete. Disconnect the front impact sensor connector, JB93. Reconnect the battery negative terminal. Turn the ignition switch to the ON position. Measure the voltage between JB93, pin 02 (White wire) and GROUND.

Is the voltage less than 4 volts? If Yes, Go to A, If No Go to B.

A. CHECK THE FRONT IMPACT SENSOR SUPPLY CIRCUIT FOR OPEN CIRCUIT

Turn the ignition switch to the OFF position.Disconnect the battery negative terminal. Disconnect the Restraints Control Module connector, CA165. Measure the resistance between JB93, pin 02 (White) and CA165, pin 19 (White). Is the resistance greater than 5 ohms? If Yes, REPAIR the high resistance circuit. Clear the DTC, test the system for normal operation.

B. CHECK THE FRONT IMPACT SENSOR RETURN CIRCUIT FOR OPEN CIRCUIT

Measure the resistance between JB93, pin 01 (Brown) and CA165, pin 20 (Brown). Is the resistance greater than 5 ohms? If Yes, REPAIR the high resistance circuit. Clear the DTC, test the system for normal operation. If No, INSTALL a new front impact sensor, Clear the DTC, test the system for normal operation.

If the fault persists, install a new RCM. Clear the DTC, test the system for normal operation.

You will notice that this procedure does not guarantee to prove the condition of the sensor and advises if all else fail, fit a new module. I imagine that at that point, you'll find the impact sensor was the cheap option!! If you didn't know, the sensor is under the plate(6 bolts) that holds the Secondary Bonnet clip and the RCM is under the centre console near the gear lever.

Take care!!

 

It may be worth taking it to a Jag. Specialist, if you need to know nearest to you there is a list on Forum or send me a PM with your Town & County & I will reply with list of nearest to you. May take a few days to reply out of UK on FRi. & Sat.


Roger.

 

Just to let everyone know I entrusted the work to Jauguar Specialists in Harrogate. They fixed it without replacing anything. It was the wiring or connectors which had oxidised and making a bad connection. As mentioned, I'd replaced all the front bulbs and must have disturbed something. Total cost around £85

 

Live feed to front impact sensor

Hi All,
read the above feed on how to test the front impact sensor.
Which i have done, the result was no voltage from the Restraints control module.
I have tried 2 other modules and still the same problem, no voltage is being sent to the impact sensor.
After changing the module, the airbag warning light goes out sometimes when just turning the ignition on but when starting the engine the light comes back on with fault code B2296 and the light flashes 4 then 2 times. same as before
any help is wecome
Paul

 

What was the result of Test B, detailed in my previous post? Sounds like it could be a wiring harness problem.

(sent from my iPad from a sun drenched beach in Jamaica!!!)

 

Hi Astromorg,
i checked both the white and brown wire from the module to the impact sensor, both ends unplugged and the reading was less than 1 omh on each wire. very strange that the light stays out some times until you start the engine.
Paul

 

Hi Astromorg,

i was thinking if i bypass the loom and put 2 new wires to the front sensor this will in turn let me know if its the loom or not.

Is the 2 wires (white/Brown) just like computer wire or are they specially made for the job. Any input on what type of wire would be good.

Paul

 

Don't have my books or car with me to look, but I can't recall such wiring being particularly special, so your idea should work. Before that, have you checked out that 4 volts is available from the appropriate pin on the restraints module? Is there a proven power supply to the module? Should be 12v on pin12, green wire, in the 24 way black connector. (Careful, there's more than one green wire!) Also don't forget to check the 22 way grey/slate connector at the left hand A Post. Your brown and white wires both pass through that. Pins 4 and 5

 

Hi Astromorg,

have looked at both block connectors and can't find any numbers on them or the plugs, do you have a picture of the plugs or control module with the numbering on it so i don't try to test the wrong one.
I know that the front crash sensor br/wh wires are on the bigger connector, second row down and last 2 on the right. i tested the white wire with the ign on and the sensor unpluged and had no voltage but i tested one of the other white and brown twisted wires and had 7.2v's on the white wire.
Thank you for your help
Paul

 

The numbers on the connectors are often difficult to see without a bright light and, sometimes, a magnifier!

The front sensor white wire is on pin 19 of the 40 way connector and the brown one is on pin 20 - that should help in identifying the rest.

The power supply on the green wire on pin 12 on the 24 way connector should be at the end of one row.

7.2v is fine - 4v is the minimum. Can you check what voltage is on the module pin 19, rather than on the wire connected to it?

 

Hi all, I too am suffering from this, I have yet to start stripping the front from the car to get to the parts, but as the car is new to me and does have some cosmetic damage, could the sensors have been set off without the air bags activating.

 

Hi All,

Need some help on a 2006 X-Type 2.2TDCi 6speed box.

I have done all the checks above and I have no voltage coming from the Restraints Module under the centre console.
I have the 12+ volts on the green wire going to the module.

Any help would be great.

Paul