Some background info

My XJR was fitted with headlamp leveling and LAD5G ballasts
One ballast failed about 4 years ago and I replaced that with a LAD5GL
As a result leveling only worked in one lamp

This was not an issue as it only moves on startup

I have now replaced the second ballast and am getting and air suspension fault in the message center. Reading the codes im getting a B1471 which is a future on the leveling.

The leveling was removed mind to late 2004 so i was hoping a flash the ASM would remove the leveling but this did not fix it.

Looking at the pinpoint test for the PWM signal it needs to test less than 10K ohms and less than 3 volts. This is with the plugs removed from the headlamps and ASM.

My next step to put a pull down resistor on the PWM output. Ill probably use around a 1m ohlm to ground.

In other words with no connection the ASM is detecting no load. The result is the B1471 (Headlamp open circuit) error. So a pull down resistor should fake a load and remove the error.

This is similar to a lamp error when installing LED lights. Those "CAN Bus" led's just have a resistor to increase the load and stop the error.

All of this got me thinking why not refit headlamp leveling
Just add a new stepper drive to the headlamp that will fix the error and restore the function. there are plenty of ready made units on ebay for a few $'s

That being the case why not fit a better leveling system. So here is the plan

1. Remove the wire from the ASM pin CR89-3
2. Fix the ASM with a pull down resistor at the ASM on pin CR89-3
2. Fit a stepper driver to the headlamps
3. Fit PWM circuit to the wire from ASM pin CR89-3. Ill get a "servo tester" from ebay.

My plan is to use 2 ready made R/C servo testers from ebay. I will use one on low beam and the other in high beam. I can get the high beam signal from the FEM. This will allow me to set the low beam height where i want and have the beams move up with high beam. The air suspension can take care of the actual leveling this will just do the adjustment.

I will be working on the error fix in the next few days and will keep this thread updated as things progress

Cheers
34by151

 

Looking forward to your progress reports 34by151!

Cheers,

Don

 

Did some more work on this today

The good news is a 1Mohlm resistor will defeat the error
The bad news is you still need a LAD5G connected

To explain that the LAD5GL uses has 3 of the 4 pins (Power, Ground, Low Beam)
The LAD5G uses 4 of the 12 pins (Power, Ground, Low Beam and ISO bus)

You need the 4th ping (iso bus) to get rid of all the errors
The next step is to try disabling it in IDS (which has the option to remove leveling)

For now Ive connected a LAD5G to defeat the errors.

Plan is now to disable leveling then add a manual level driving the stepper motors directly. The objective being to raise the low beam lamps when high beam is selected.

Cheers
34by151

 

With the help of Cambo we have removed the error by changing the car configuration.

The issue is the LAD5G (12 pin ballast) has a connection to the iso bus where the LAD5GL (4 pin) does not

In cars fitted with the LAD5G the ASM looks for messages from the ballasts. When none are present you get the yellow CEL and "Air Suspension Fault" in the message center.

This only occurs if you have upgraded both ballasts, upgrading only one will not produce the error. It will show as a missing/failed module in SDD though.

So the answer in converting both is to reconfigure the car for halogen headlamps. This requires a few things to be done and its not possible to do with a mongoose. First the VID block needs to be edited and uploaded then the IC, ECM and ASM needs to be re-flashed.

The IC/ECM needs to be flashed to update the VID block. The ASM needs to be re-flashed to disable the ISO bus signal. In other words halogen headlamps are dumb (no iso bus signal)

The ballasts dont care what the car is configured for because if they have power the lights come on.

If you still have one LAD5G in the system the lamp will go up and down , as normal, when you start the car but it will not move from this point. This is a function of the ballast.

Regardless of which type ballast you have the headlamp flap will still operate correctly on high beam.

What you loose is the headlamp delay function on the stalk. Auto lamps still operate as normal. If you select on of the 3 delays it will operate as auto.

If anyone needs this update to go with upgraded ballasts PM Cambo to arrange him to update your VID block and reprogram the car.

Thanks again to Cambo for his help working this out

Cheers
34by151

 

Your article was very useful as I run into the same problem. You indicate you planned to fix the problem with a pull-down resistor. Did it work? What value did you use? You write 1 ohm, but it sounds to me as too low.

Thanks

 

harlock, he wrote 1m ohm which is 1 megaohm. One megaohm is equal to 1,000,000 ohms,
John