jrprich

My 03 hasn't had the dreaded "Service Active Handling" message until yesterday. I activated the Emergency Flasher while approaching a spun out car on the freeway and my "Service Active Handling" popped on and I couldn't clear it until I shut off the engine. On restart there was no message nor was there one after driving. When I got back home while sitting in the driveway I turned on the Emergency Flashers again to test and bingo the SAH warning came back on.

Any ideas?

Thanks,
Jim

zachaeous

I had something similiar happen to my car. I was installing LED taillights and upon putting them in the rear tail lights started flashing like the emergency flashers (all four rear taillights would flash when either turn signal was applied) and the service active handling message also flashed on the DIC.

The BCM set a code also. I corrected the light flashing by adding resistance to the tail light circuit and cleared the codes:

TCS C1295H

BCM B2578H

After getting the rear tail LEDs with the proper resistance no more DIC Message or codes setting. Been two days and no more problems.

I have no idea what caused the DIC Message for the traction control. I think the BCM Message was caused by the load sensed to the tail light circuit being off due to the LEDs.

jrprich

Thanks,

But I installed a bypass digital flasher for the LEDs when I installed them and they do not HyperFlash. So I doubt that is the cause.

Jim

Bill Dearborn

Just use the DIC to show the codes when the Service Message is present.

Quick and easy to do. First, use the DIC to clear all codes, then drive the car apply the emergency flashers and when the Service Message appears pull off the road and run the codes again.

C5 is the only car ever produced that permitted owners to read any code that might exist in the car. Far better than an OBD II scanner which can only read about 55% of the codes.

Bill

GCG

Check your codes to see if you have a DTC C1295. If you do, your problem is probably caused by your LED tail lights.

Therefore if the path to ground is open, or the EBCM thinks is open because now you have LEDs, the code will be set and the Service Traction Contron and Active Handling messages will appear. A hyperflash harness will not prevent this from happening, it only prevents turn signal hyperflashing.

You will need to connect a shunt resistor in your tail lights circuit to provide the ground path the EBCM expects to see for those 5 volts

jrprich

Thanks, I will check.

Where would one purchase a shunt resistor and what spec resistor would one select?

Jim

GCG

I don't have a top of my head value for the shunt(s), but let's give it a try.

With ignition on and the stop light switch inactive (no brakes applied) the EBCM applies 5v to the stop light filaments through what seems to be a "current-limited" circuit (otherwise we would be driving around with stop lights somewhat lit).

A light bulb has a non-linear resistance because it varies with the temperature of the filament. For instance:

1. I just measured the "cold" resistance of a 3057's stop light filament and it is around .5 ohm
2. I applied 1.5v to it, not enough to get it lit or noticeable hot, and it drew .75A so that means that the filament was 2 ohms
3. With 4v applied it got lit, although obviously not at full blast, but enough to be seen and get hot. It drew 1A, so under those conditions the bulb's filament was 4 ohms.

Providing 5v through a current-limited circuit causes the voltage to drop because the source can't provide the 4 to 5 Amps (4 bulbs @ 1+ Amps per bulb) the bulbs would draw with 5v. I have not measured it, but I have read it goes down to 1.87v, which should be under the threshold where the bulbs begin to produce light.

So it seems this is the EBCM's mechanism to test if the stop lights are blown or not:
It applies 5v and if the voltage goes down to 1.87v everything is fine, or if it stays at 5v (or above a certain threshold between 1.87 and 5) the ground path is considered open and the C1295 is set, along with the corresponding warning messages.

Following this line of thought, when the 5v are applied each stop light filament begins at .5 ohm, pulls more current than the circuit can supply, which brings down the voltage, and stabilizes at around 2 ohms with 1.87v. At this point, the total resistance of the 4 stop lights connected in parallel would be 2÷4=.5 ohm. In order to "tame" this a bit, let's "venture" (I haven't tested it) that no code would be set if at least 1 stop light is good. This way we go can go back to 2 ohms and if we spread it among the 4 stop light filaments, the power dissipation in each resistor would be minimized (this is why the LED halo tail lights have a resistor with a built-in heat sink mounted at the back of "each" housing).

To have a total of 2 ohms using 4 equal resistors in parallel they should be 8 ohms each and, since they get applied the full 12v when braking, each one of them should be able to dissipate more than 24.5w (14x14÷8).

So 4 resistors of 8 ohms and let's say 50w, like this one:


connected between Dark Green and Black in the passenger's side, and between Yellow and Black in the driver's side.

Perhaps you can get away with fewer resistors by adding (or removing) them one at a time and testing in between

msandym

I think this is happening to me . I had brakes installed , after a month or so that message appeared . When I shut it off , the message cleared , but it comes back . I got a c1226 code ?

BmoreRnsDeep

I have it and service traction control and service abs and stabilitrack. I must have a fried Abs module because i cant clear the codes.

jrprich

UPDATE: 11/14

The code that keeps getting set is 28-TCS 1295

But the problem has spread............now if I use my Right turn signal with my parking lights On or my Headlights on the TCS throws the 28-TCS 1295.

I tried swapping the outer left rear LED to the outer right......no change, still sets the code with use of the right turn signal while my parking lights On or my Headlights are on. Also with E Flashers in use.
Next I tried replacing the right and left outer LEDs with stock filament bulbs. This change stopped the TCS from setting the code with use of the right turn signal while my parking lights are On or my Headlights are on. But the E flashers will still set the code.
Next I swapped out the inner LED bulbs with stock filament bulbs. This change stopped the TCS from setting the code with use of the right turn signal while my parking lights are On or my Headlights are on. But the E flashers will still set the code. I was hoping that moving to all 4 tail lamps as stock would also allow the E Flashers to work without throwing the code.....but no luck.

So at present I have LEDs in my two outer tail lights and stock filament bulbs in the two inner tail lamps. This stops the code when using the right turn signal while my parking lights are On or my Headlights are on. But the E flashers will still set the code.

I have not tried resistors yet as I am not sure which ones will work and I would prefer not to have the heat these give off.

BTW,

I had the exact same LED rear tail lamp bulbs and hyper flash harness in my 99 and had none of these issues. I simply moved the 4 LED rear tail lamp bulbs and hyper flash harness from my 99 to my 03.

Would appreciate suggestions at this point..................

GCG

Considering all you have done, if I were in your shoes I would put it back to completely stock regarding LEDs (all around, inside and outside) and then, if everything is fine, I would work my way back one LED at a time until the culprit is found.

I know you said you put back to OEM all 4 taillights simultaneously, but I would take it one step further and take out of the equation the hyperflash harness. Remove it as part of putting everything back to stock. That's what I would do.

LEDs in the C5 taillights usually require shunt resistors to avoid code 1295. That's why the popular rear halo LED housings have a built-in resistor in each unit. Take a look at this picture: it's the module inside the aluminum heat sink.


It seems in your case something else is happening because everything was not fine again after putting back the 4 incandescent bulbs.

jrprich

GCG,

I appreciate your time and suggestion!

I was thinking the same. Just weird that the same exact components were in my 99 for several years with no codes and no issues.
I can't put it back to completely stock regarding LEDs (all around, inside and outside) as my HVAC and Bose also have had LED conversion. So I think I will do it in stages and record what happens starting with the Hyperflash harness.
I really do not want to use resistors

Thanks again,

Jim

GCG

You can still try everything back to stock except the headunit and A/C.

Work systematically and I'm sure you'll get it!

Bob_VII

Have you verified that all lights work? I had a similar issue, using either turn signal would immediately throw a TCS warning and code, which turned out to be due to my right rear brake/signal light not working because of a broken wire in the harness next to the transaxle. I'm not sure why that would have that effect, but it did disappear with that repair.

Pizzano

I have a similar problem I posted in the General section, description below



Maybe the described results I list below might jolt another problem.

1) the battery was disconnected last weekend when some top end the valve springs etc was done, also the alt was disconnected and moved out of the way.
2) the car drove fine after upgrades.
3) while doing some replacement of the front spoilers, I noticed I had no front turn signals in front.
4) I just purchased the vehicle 2 months ago and it has LED tail lights, also LED interior and backup lights,they did have the hyper flash issue, so I installed the Radio Flyer solution, and the hyper was fixed.
5) Then I noticed that in the front turn signals there was LED bulbs just floating in the front turn signal lenses.
6) I tore apart the front headlight so I could get my paws down to get to the turn signal housing I installed the loose LED light and tested it by turning on the lights and that is when I seen the battery drain (according to the DIC, it went down to 9.6 volts), and then the codes popped up , such as "service the traction control", radio etc.
7) I removed the LED bulbs and replaced with factory called for bulbs 3157 bulbs in amber .

8)Now I have turn signals in front, but have the issue that I started this post about, and yes the Optima Red terminals are tight.

And as far as when I turn the vehicle off, it imediately shows 10.9 volts and the "service Traction control" pops up (hense I would imagine the TC needs a certain voltage to operate).
I drive the vehicle and everything according to the DIC shows between 12.5 -13.2 volts on the DIC.

[[None of this started until I tried plugging in the front LED turn signal on the passenger side]]

Thats it in a nutshell folks, from what I can tell , plugging in that LED that was loose in the front signal snowballed something.

I apologize for the long post , If any GM Techs out there can chime in that would be great.

Myself , I am a HVAC Journeyman Tech for 30 yrs so I know how to use a meter and so on .

Any other input would be greatly appreciated
__________________

jrprich

Thanks,

Yes, all lights are working.

jrprich

Five days of driving and using the hybrid setup with the two outboard tail lamps having halogen bulbs.......no codes since the swap.....
I did pick up a new pair of LED tail light bulbs (different brand) that I will swap into the outboard tail lamps as a test soon.

GCG

¿So everything is perfect now? ¿No code is being set with the E flashers as you previously reported above?

jrprich

I wish.............
I haven't had time yet to trobuleshoot further. But at least I don't get a code when using the turn signals.

Rob 02

Same problem and went to the most powerful LED's I could find (Cree 5w 30w equivalent). Still had the problem and realized my 3rd brake light wasn't working. Replaced it and all is well.