Problems with LH Headlight and Taillight

[lg54]

Hello all,

New to this site, coming from Maseratilife. Im reaching out here because I need more imput to a problem I have encountered in my car, and I am at a lost. Taking it to the dealer is not an option where im from, so DIY it is. Car is a '12 Granturismo

LH headlight will not stay on. When I turn it on, DRL will light up for a split second then turn off. With the headlights off, momentary high beams work, with them on, it does not. Low beams do not work, not even flicker on.
LH Taillight does the same, when i turn on lights, it will turn on for a split second then flicker off. Brake light works ok. Blinkers will work for a split second then turn off.
RH side all works good.

I have cloned and replaced BCM thinking it was that, checked fuses and all is ok.

On the dash i am getting check side lights and adaptive light control unavailable.

I am getting the following codes with my scanner

• B1040 Twilight Sensor - No Response
• B1041 Rain Sensor - No Response
• B1004 Serial Line A-Bus-Link Not Ok
• B1007 LH Direction Indicators - SC GND /5w instead of 21W
• B1013 LH Position Lights - SC GND (BOTH)

 

[CatmanV2]

Welcome to the other place. Hopefully the smarter minds than I can help with this one

C

 

[strictly]

Hello all,

New to this site, coming from Maseratilife. Im reaching out here because I need more imput to a problem I have encountered in my car, and I am at a lost. Taking it to the dealer is not an option where im from, so DIY it is. Car is a '12 Granturismo

LH headlight will not stay on. When I turn it on, DRL will light up for a split second then turn off. With the headlights off, momentary high beams work, with them on, it does not. Low beams do not work, not even flicker on.
LH Taillight does the same, when i turn on lights, it will turn on for a split second then flicker off. Brake light works ok. Blinkers will work for a split second then turn off.
RH side all works good.

I have cloned and replaced BCM thinking it was that, checked fuses and all is ok.

On the dash i am getting check side lights and adaptive light control unavailable.

I am getting the following codes with my scanner

• B1040 Twilight Sensor - No Response
• B1041 Rain Sensor - No Response
• B1004 Serial Line A-Bus-Link Not Ok
• B1007 LH Direction Indicators - SC GND /5w instead of 21W
• B1013 LH Position Lights - SC GND (BOTH)

View attachment 146263

So first of all i don't have the experience but I can suggest the following

There is a master and slave ecu these are located in the headlights.

1. Get you hands on maserati training academy advanced electronics volume 2 it's free in various places on the Internet. See pictures

2. Get your hands on the 2011 to 2017 granturismo workshop manual this has wiring diagrams its also free on the Internet but harder to find. See pictures

3A. Figure out the electrical link between the left headlight and left taillight...broken wire in trunk wiring harness maybe? (this could be ******** advice so tread with care)

3. Using the above documents verify you are getting power at the fuses for the headlights. There look to be some relays controlling power to the fuses

4. Carefully measure power and check for ground at the headlight ecu...I don't actually know the best way to do this as I don't know how to. You might be able to unplug the electrical headlight ecu connector and either measure on the appropriate pin or measure with a back probe. Do with care!

5. Check your electrical ecu connections have no corrosion

6. Verify you canbus continuity but be very careful here I don't know how to do it and you could easily screw something up

7. A bit like item Verify the can bus communications are working but I have not learned how to do that. Someone will know!

keep us posted and welcome to the dark side

 

[strictly]

P.s to quote maserati academy

The activation of the headlights (and the different individual lights integrated in the front headlight units) is managed by the body computer (NBC) and the CPL, using input signals from the light switches and the twilight sensor

------

I would still start with the basics like looking for corrosion in the electrical connections of the headlight checking the relays and power and fuses before moving on to checking power and ground at the electrical connections.

If that all checks out then repeat the above but looking at the CPL and using the information in item 1 and 2 in my post above to find common wiring connections or how to check the can bus. Maserati academy does talk about checking can bus.

Good luck. You will probably find it's something simple like a bad connection or electrical corrosion. We live in hope anyway

 

[lg54]

Strictly,

Thank you for all the knowledge you have shared. I did not know workshop manuals and Training Academy documents were available. This has given me hope when I was just about to give up. I'm now searching for these documents, although from the research I have just done, they don't seem so easy to get, but I will search hard, this has given me hope.

Thanks immensely.

 

[strictly]

Strictly,

Thank you for all the knowledge you have shared. I did not know workshop manuals and Training Academy documents were available. This has given me hope when I was just about to give up. I'm now searching for these documents, although from the research I have just done, they don't seem so easy to get, but I will search hard, this has given me hope.

Thanks immensely.

If you get stuck drop me a message. I'll point you in a closer direction on those documents...wink

P.p.s

The a bus is suspect or the twilight sensor is suspect. If your alarm siren and windscreen wipers seem OK then maybe the a bus is fine and the twilight is suspect. You can verify the a bus using a multimeter and an oscilloscope so maybe start by verifying it is good like on the windshield wiper node then move on to checking it on the twilight sensor

 

[CatmanV2]

Thank you for all the knowledge you have shared. I did not know workshop manuals and Training Academy documents were available

I *think* this is the one @strictly is referring to

Advanced Electronics 2-Chassis and Body.pdf

drive.google.com

There are others here:

GT – Google Drive

drive.google.com

C

 

[lg54]

Thank you.

Work shop manual has been found, working on the Training Academy documents.

Siren does not emit sound, and upon locking, I get a double flash of orange (hazard) lights. It was like this before having headlights and tail light go out.

Twilight sensor might be good, because when turning light switch to auto, lights turn on, but will have to verify.

The tricky part is that tail light turns on for a split second then turns of, and same for headlight side marker.

If you get stuck drop me a message. I'll point you in a closer direction on those documents...wink

P.p.s

The a bus is suspect or the twilight sensor is suspect. If your alarm siren and windscreen wipers seem OK then maybe the a bus is fine and the twilight is suspect. You can verify the a bus using a multimeter and an oscilloscope so maybe start by verifying it is good like on the windshield wiper node then move on to checking it on the twilight sensor

 

[lg54]

I *think* this is the one @strictly is referring to

Advanced Electronics 2-Chassis and Body.pdf

drive.google.com

There are others here:

GT – Google Drive

drive.google.com

C

Thank you Immensely Catman!

 

[strictly]

Thank you.

Work shop manual has been found, working on the Training Academy documents.

Siren does not emit sound, and upon locking, I get a double flash of orange (hazard) lights. It was like this before having headlights and tail light go out.

Twilight sensor might be good, because when turning light switch to auto, lights turn on, but will have to verify.

The tricky part is that tail light turns on for a split second then turns of, and same for headlight side marker.

Ok so good luck. I know about bit but not enough to be that helpful.

Obviously start with the basics but if you get into checking the a bus and can bus and you might then explain how you did so I can piggy back off your learning.

It might very well be simple so don't give up on the simple stuff yet but the documents will help you hone in on the problem as it gets more complex.

Don't give up to you find it. My nearest specialist is 200 miles or more away so fixing myself like you really is the only option. I rely on learning from others when I get stuck.

 

[strictly]

Thank you.

Work shop manual has been found, working on the Training Academy documents.

Siren does not emit sound, and upon locking, I get a double flash of orange (hazard) lights. It was like this before having headlights and tail light go out.

Twilight sensor might be good, because when turning light switch to auto, lights turn on, but will have to verify.

The tricky part is that tail light turns on for a split second then turns of, and same for headlight side marker.

P.p.p.p.s

I was just thinking about your problem some more. Don't replace anymore parts. As I said above check all relevant electrical connectors for corrosion, tightness, power and ground. If everything seems to be OK. I would start validating the A bus voltage, signal and integrity before moving in to the cab bus for the same.

What ever happens keep us posted so that we can fully track a method and solution to help those that follow in your foot steps

 

[lg54]

P.p.p.p.s

I was just thinking about your problem some more. Don't replace anymore parts. As I said above check all relevant electrical connectors for corrosion, tightness, power and ground. If everything seems to be OK. I would start validating the A bus voltage, signal and integrity before moving in to the cab bus for the same.

What ever happens keep us posted so that we can fully track a method and solution to help those that follow in your foot steps

Thank you. It certainly is a lot of information to digest but slowly im reading the documents. i will start diag soon. Hope is something easy.

 

[CatmanV2]

Thank you. It certainly is a lot of information to digest but slowly im reading the documents. i will start diag soon. Hope is something easy.

Told you they were good

C

 

[lg54]

So I did some basic diag. Started with my tail lights.
Head lights and tail lights seem to be interconnected somehow.
Swapped upper tail lights and no change.
I can get the lower tail light to stay on, but if I press the brake it will go off (see video) Seems something is overloading ecu maybe?

See video of upper tail light turning on for a split second.

When I loose the lower tail light i also loose the position lamp (vertical strip) in the headlight, this is why i say they are connected.

Could the headlight master ecu be causing this issue? Something along the lines of the NFR-NFA modules.

Now my right side headlight low beam is not turning on. I would like to try a Master headlight ECU. Is this something that can be replaced?

 

[James3200GTA]

Maybe a simple question, but did you check the grounding point of the lights? On older (analogues) cars when the grounding point has corrosion or high resistance due to whatever, it sometimes happens that brake light influence tail lights and taillights influence direction indicators as the electric current finds other ways back to the - terminal of the battery.

I can imagine that on these driving computers with LEDs this can cause all sorts of havoc and strange behaviour.

 

[strictly]

So I did some basic diag. Started with my tail lights.
Head lights and tail lights seem to be interconnected somehow.
Swapped upper tail lights and no change.
I can get the lower tail light to stay on, but if I press the brake it will go off (see video) Seems something is overloading ecu maybe?

See video of upper tail light turning on for a split second.

When I loose the lower tail light i also loose the position lamp (vertical strip) in the headlight, this is why i say they are connected.

Could the headlight master ecu be causing this issue? Something along the lines of the NFR-NFA modules.

Now my right side headlight low beam is not turning on. I would like to try a Master headlight ECU. Is this something that can be replaced?

Did you pull the electrical connectors and check they have no corrosion on the terminals then checked for power and earth on the right pins. I really would tick of the basics before moving on to looking at the can bus signals...the ecus can get easily confused rather than be to blame.

I think you absolutely have to jump into the electrical diagnosis rather than try and guess and throw parts at it. It might be a steep learning curve but "when the day is none after work time" is free for most of us

 

[lg54]

Ok so got some inspiration from your guys comments.

Did more diag today. Tried different things and was ready to give up. Decided to switch tail lights as last resort just to see if something changed.

Lo and behold, it worked! Apparently my LH body taillight is shorted inside. The problem followed the tail light. When i tried RH tail light on LH wiring it worked perfect. As i write this, i am looking for tail lights online to order ASAP.

Now I need to focus on my headlights. I believe this is going to be easier as there are some wright ups about low beams out on headlights. I will start diag on them soon. Suggestions on what to check are always welcomed, either way I will keep you updated. Thanks all for such great help.

 

[strictly]

Good work. Any sign of water ingress? That seems like it would be the most probable cause.

This thread below hints that while not for the feint of heart it must be possible to have the taillights apart. If so you could then access the circuit board and take a look at it...

Link here

If you just buy another one. Which im sure most of us would! You could have a go at taking apart your now redundant taillight. Then if successful explain how you did it