Codes C0040 & C006C with Limp Home Mode - fixed!

[Marvin2488485]

A few weeks ago the wife and I were on our annual spring trip to warmer weather, we have a 2015 Spyder RT Limited, we trailer it from South of Indy to Brunswick GA, we spend two weeks riding and enjoying the sights and weather. It was Thursday of the lass week of our trip, we headed down to Saint Augustine had lunch and enjoyed the sights, we headed back to Brunswick, about 40 miles from Brunswick we were getting low on fuel, stopped and filled up, got back on the interstate, set the cruise and headed to our B & B, was riding along and the bike jumped out of cruise and started to slow down, also the check engine light came on, I grabbed the throttle and got the bike back up to speed, check engine light went out and everything seemed normal, set speed control again and cruised in to Brunswick. We stopped at a sub place to get a bit, came out stuck the key in the ignition, turn the key and noticed that I had no light or movement from the dashboard, nothing, like the battery was dead, I pull the tools from under the seat, removed the battery cables, didn’t notice anything unusual, put the battery cables back on tightly, turned the key and everything look like it was supposed to, got on the bike and headed to our B&B, about 2 miles from our destination the check engine light and limp mode came on, we pulled up to my bike trailer wife got off and I put it up for the night. The next day I pulled the battery cables off again cleaned up cables and post, they weren’t really dirty, put the cables back on the battery, tightened the cables, road down the road for a few miles no faults, everything looked good, turned around when back to the trailer, just as I was pulling it back on check engine light and limp mode came back on. I told the wife I didn’t trust riding it anywhere so I tied it down and got it ready for the trip home.

After being home for a few days I decided to figure out what was going on with the RT, I got the error codes, it had two of them, C0040 and C006C:
C0040 module:VCM
Brake pedal switch failure (BLS).
Mechanical defect or wrong mounting of BLS.
Brake Light circuit open or defective brake light bulbs.
Check BLS (brake light switch) fault on ECM .
Check brake light bulbs.
Check BLS.

C006C module:ECM
VSS CAN (control area network) rate message error.
Communication on CAN BUS not reliable.
No external troubleshooting possible.

Well I went back to the bike and check the bake lights, had none, no tail lights, no emergency lights, so I thought it’s time to take it to a shop, I have 5 year warranty, one more thing, I pulled the fuse cover off and checked the fuses for brake and tail lights, one was a 10 amp fuse the other was 15 amp fuse, both were blown, got two more fuses and installed, turned key on, no lights, checked fuses and both again were blown, I got to thinking what would make the fuses blow, I was at a loss, the only thing that come to mind was a modification I had done years earlier when I first got the bike, I installed a smart break light module from gear break, it installed under the seat and connects to the break light wiring harness, I decided that I would remove it because I didn’t want to take it in for warranty repair and it be the problem and I would have to pay, so I removed the module, put a new 10 & 15 amp fuse in and the bike was fine, took it for a test ride no problems.

I got to reading about the Smart break light module and noticed that it had a lifetime warranty, so I sent a email to GearBrake.com and they are replacing the unit, no charged.

Hope this will help someone in the future if they have similar issues

[larryd]

THANK YOU...I wish everyone would follow up on their posts when the problem/problems are cured...larryd

[thereverend]

thank you sir; I also have the GrearBreak modual installed on two of my Spyders, if anything goes wrong with them I now have an idea of where to look.

[RTSJohn]

Excellent write up. Being new to this Spyder world I find these posts to be very educational. Thanks to you and all the others who so willingly share these experiences.

[LeftCoast]

[PW2013STL]

Great job of tracking down the problem and solution!

[stmike 1800]

If in the future you have blown fuses, get two spade terminals that will fit were the fuse came from. Now connect a large sealed beam headlight (the ones all the old cars had ) in parallel with the fuse terminals (from one fuse terminal to one side of the headlight out the other side of the headlight to the other fuse terminal) Now if the headlight is on you have a ground, disconnect wires till the head light goes out.

[Chupaca]

Have always had as step one..... check all mods that could affect the unit. You found the problem and hope they can tell you what went wrong with the unit. But nice it has a great warranty and they stand behind their products...

[stevencovert]

I just had the exact codes after a hard stop in 45mph traffic. No blown fuses though - but I do have a couple things attached to the brakes: trailer wiring, and a flasher for LEDs strips on the trunk. Thanks for the write up!

[gkamer]

THANK YOU...I wish everyone would follow up on their posts when the problem/problems are cured...larryd

Me too. Someone posts about a problem, several people offer suggestions, but you never hear anything back from the OP. Makes me crazy.....

[windancer]

To start out, I want to say how valuable and informative this website is!! I have been “lurking” on SpyderLovers for quite awhile, but now have something to say….

My wife is on her 3rd Spyder (2018 F3t), while I have been riding BMW’s for almost 500,000 miles. My wife talked me into getting a Spyder. We bought a very nice pre-owned 2018 RTL from Proshop Motorsports in Henderson, Nevada. Good People!

The weather warmed up, and we went for a couple of rides. I noticed the cruise control wouldn’t engage. “Funny, it worked when I drove it home”. Then the bike went into “Limp Home Mode” a couple of times, with an code of C0040 and C006C. The bike then wouldn’t go faster than 59 MPH—not very safe when traffic is running at 70 MPH+! Anyway, I remember reading on Spyderlovers how to make “Limp Home” go away (turn key on/off three times, etc). The problem went away for a couple hundred miles, but reared its ugly head again yesterday. All this time the cruise control was DOA.

Researching on this site, I found that there are a few possibilities for this fault:
1. Blown fuse
2. Loose battery cable
3. Blown Brake Lite bulb
4. Bad Right-hand switchgear (Cruise Control)
5. Bad brake switch
6. ????

Now I’m a pretty good shade tree mechanic, and can fix most anything on a BMW. The idea of taking the RT back to the dealer for repair was the last thing I wanted to do. So I tackled the problem myself—with help from SpyderLovers and my downloaded Shop Manual.
Results:
1. Fuses were all OK
2. Battery cables were tight (new battery, kept on Tender)
3. Brake Bulbs are all LED, and functioning as they should.
4. Carefully took the Right-hand switchgear apart, sprayed it down with contact cleaner, and did a continuity test at the junction (located under RH fender). Everything was working fine.
5. Seems that the brake switch has been the problem for many folks. The Brake switch is located down there by the RH floor board. Gotta take off muffler, cat, etc – just to get to the (REALLY TIGHT) bolts holding the whole assembly to the frame. I learned a lot of new French-Canadian swear words, but eventually got to the switch. Actually, there are TWO microswitches on the 2018, both actuated by a ‘cam’ on the brake pedal. The one that typically fails is the one that controls the brake lite circuit and is triggered by the first little travel of the brake pedal—which is why you must make sure the pedal moves freely and completely returns to the ‘UP’ position, and that you don’t ‘ride the brake’. The other microswitch is actuated when the brake pedal goes all the way down (perhaps if your hydraulic system fails). Anyway both switches on my bike were clean and free from any debris. Cleaned with contact cleaner, bench tested with continuity tester, and everything check out OK. Lubed the moving parts, and buttoned it up. Bike didn’t throw a fault for several hundred miles, so I figgered it’s fixed. But still no Cruise Control. Oh well….

6. Then I read THIS THREAD started by Marvin2488485. A revelation!!
Here’s some help: the cruise control will not engage if there is anything amiss in the braking system. I studied the wiring schematic from my downloaded shop manual. I threw a voltmeter on the brake system wire (WHITE WIRE, located at the rear junction or one under the ass of the bike). It should read zero volts when bike is off or when the brake pedal is at rest (i.e. brake lights OFF). Then it should read 12-14 volts when brake pedal is depressed (i.e. brake lights ON). Well, it was showing ~ 5-6 volts ambient – brake pedal at rest/bike on. Hmmm. Why?? I reasoned that ANY voltage in that circuit when the brake is at rest will cause the computer to think that the brake is engaged, and thus prevent the cruise control to work. “If you’re braking, you can’t use the cruise control”. If the voltage is sufficient and consistent, the computer will think “Something is wrong. Let’s throw a fault for my owners safety, and slow him down to 59 MPH”.

Marvin mentioned that he had aftermarket brake lights on his bike, which were causing his fuses to blow (replaced by manufacturer, which solved his problem). I realized that my bike had two aftermarket brake lights: one on the tip of the rear fender, and a Custom Dynamics High-Mount Running/Brake light sold by Lamonster. Great lights. Real attention getters! Both are LED arrays. They are posi-tapped into the Brake Circuit (White Wire) for full brightness (BRAKE); The Running Lights use the same LED’s--via an in-line resister, tapping the Orange Wire circuit. Two diodes protect circuits from “backloading”. This in-line resister/diode set is very tiny, but essential.

I disconnected both auxiliary lights, and voila!! The White Brake Circuit tested 12 volts when brake pedal is engaged, and ZERO volts when at rest—as it should be!! ZER0, zilch, nada. The resister/diode thingy on the Custom Dynamics Light had failed--feeding voltage from the running light circuit back into the brake circuit. hence the computer thought the brake was always engaged, preventing the cruise control from even going on, and often causing the “Limp Home Mode”.

I buttoned everything up and took the bike for a test drive. Good News: I now have CRUISE CONTROL!!! I don’t expect to see the dreaded “Limp Home Mode” or the “C0040 and C006C” error code again.
Sorry this post is so long and technical. Hope this helps someone out there whose tearing their hair out. The rule: try removing aftermarket stuff to see if your problem goes away.

Did I mention how much I love SpyderLovers website??!!

[safecracker]

Great write ups!!!

[EdMat]

windancer,

You should copy and past this into a stand alone thread. Great post.

[BLUEKNIGHT911]

To start out, I want to say how valuable and informative this website is!! I have been “lurking” on SpyderLovers for quite awhile, but now have something to say….

My wife is on her 3rd Spyder (2018 F3t), while I have been riding BMW’s for almost 500,000 miles. My wife talked me into getting a Spyder. We bought a very nice pre-owned 2018 RTL from Proshop Motorsports in Henderson, Nevada. Good People!

The weather warmed up, and we went for a couple of rides. I noticed the cruise control wouldn’t engage. “Funny, it worked when I drove it home”. Then the bike went into “Limp Home Mode” a couple of times, with an code of C0040 and C006C. The bike then wouldn’t go faster than 59 MPH—not very safe when traffic is running at 70 MPH+! Anyway, I remember reading on Spyderlovers how to make “Limp Home” go away (turn key on/off three times, etc). The problem went away for a couple hundred miles, but reared its ugly head again yesterday. All this time the cruise control was DOA.

Researching on this site, I found that there are a few possibilities for this fault:
1. Blown fuse
2. Loose battery cable
3. Blown Brake Lite bulb
4. Bad Right-hand switchgear (Cruise Control)
5. Bad brake switch
6. ????

Now I’m a pretty good shade tree mechanic, and can fix most anything on a BMW. The idea of taking the RT back to the dealer for repair was the last thing I wanted to do. So I tackled the problem myself—with help from SpyderLovers and my downloaded Shop Manual.
Results:
1. Fuses were all OK
2. Battery cables were tight (new battery, kept on Tender)
3. Brake Bulbs are all LED, and functioning as they should.
4. Carefully took the Right-hand switchgear apart, sprayed it down with contact cleaner, and did a continuity test at the junction (located under RH fender). Everything was working fine.
5. Seems that the brake switch has been the problem for many folks. The Brake switch is located down there by the RH floor board. Gotta take off muffler, cat, etc – just to get to the (REALLY TIGHT) bolts holding the whole assembly to the frame. I learned a lot of new French-Canadian swear words, but eventually got to the switch. Actually, there are TWO microswitches on the 2018, both actuated by a ‘cam’ on the brake pedal. The one that typically fails is the one that controls the brake lite circuit and is triggered by the first little travel of the brake pedal—which is why you must make sure the pedal moves freely and completely returns to the ‘UP’ position, and that you don’t ‘ride the brake’. The other microswitch is actuated when the brake pedal goes all the way down (perhaps if your hydraulic system fails). Anyway both switches on my bike were clean and free from any debris. Cleaned with contact cleaner, bench tested with continuity tester, and everything check out OK. Lubed the moving parts, and buttoned it up. Bike didn’t throw a fault for several hundred miles, so I figgered it’s fixed. But still no Cruise Control. Oh well….

6. Then I read THIS THREAD started by Marvin2488485. A revelation!!
Here’s some help: the cruise control will not engage if there is anything amiss in the braking system. I studied the wiring schematic from my downloaded shop manual. I threw a voltmeter on the brake system wire (WHITE WIRE, located at the rear junction or one under the ass of the bike). It should read zero volts when bike is off or when the brake pedal is at rest (i.e. brake lights OFF). Then it should read 12-14 volts when brake pedal is depressed (i.e. brake lights ON). Well, it was showing ~ 5-6 volts ambient – brake pedal at rest/bike on. Hmmm. Why?? I reasoned that ANY voltage in that circuit when the brake is at rest will cause the computer to think that the brake is engaged, and thus prevent the cruise control to work. “If you’re braking, you can’t use the cruise control”. If the voltage is sufficient and consistent, the computer will think “Something is wrong. Let’s throw a fault for my owners safety, and slow him down to 59 MPH”.

Marvin mentioned that he had aftermarket brake lights on his bike, which were causing his fuses to blow (replaced by manufacturer, which solved his problem). I realized that my bike had two aftermarket brake lights: one on the tip of the rear fender, and a Custom Dynamics High-Mount Running/Brake light sold by Lamonster. Great lights. Real attention getters! Both are LED arrays. They are posi-tapped into the Brake Circuit (White Wire) for full brightness (BRAKE); The Running Lights use the same LED’s--via an in-line resister, tapping the Orange Wire circuit. Two diodes protect circuits from “backloading”. This in-line resister/diode set is very tiny, but essential.

I disconnected both auxiliary lights, and voila!! The White Brake Circuit tested 12 volts when brake pedal is engaged, and ZERO volts when at rest—as it should be!! ZER0, zilch, nada. The resister/diode thingy on the Custom Dynamics Light had failed--feeding voltage from the running light circuit back into the brake circuit. hence the computer thought the brake was always engaged, preventing the cruise control from even going on, and often causing the “Limp Home Mode”.

I buttoned everything up and took the bike for a test drive. Good News: I now have CRUISE CONTROL!!! I don’t expect to see the dreaded “Limp Home Mode” or the “C0040 and C006C” error code again.
Sorry this post is so long and technical. Hope this helps someone out there whose tearing their hair out. The rule: try removing aftermarket stuff to see if your problem goes away.

Did I mention how much I love SpyderLovers website??!!

Absolutely excellent diagnostics ( on your part ) Thanks ..... My 14 RT brake light / cruise control system works as designed , however I ADDED two LED brake lights to the mix and didn't use any diodes .... nothing has been affected by this addition ... it seems odd ..... Thanks for your efforts ... Mike

[windancer]

Mr. Knight:
I believe if any LED arrays is used for 'dual luminosity'-- i.e. full brightness for BRAKE and half brightness for RUNNING--they should have in-line diodes to prevent unwanted feedback between the BRAKE circuit (White Wire) and Running Light (Orange Wire). This could be built in to the Light module (it should have three wires: Ground, one for brake, and another for running); else it would be external, splitting the positive wire into the two circuits before going into the Array. Oh, and the 'half-bright' ciruit would have a resister inline to drop the voltage.
My problem was that one of the diodes had shorted out, feeding the 'half voltage' back into the brake circuit, causing an ambient voltage of about 5 volts back into the BRAKE circuit, thus fooling the computer into thinking the brake was constantly being applied (since the Running Lights are always ON), and therefore preventing the cruise control from engaging, and causing the fault code. The BRAKE circuit needs to be null/zero when the brake pedal is at rest.

Mr. EdMat--
I posted to this post here to build on the conversation that Marvin had started in 2019, becuase his is properly titled, and should reduce redunancy for those fighting the same battle.

Ken Götzen-Berg

[FrogmanDave]

however I ADDED two LED brake lights to the mix and didn't use any diodes

If it is just brake lights you wouldn't need a resistor. That is only required if the same bulb is used for running lights.