3 bars of death, C1330 Error Code, and non-starting transmission issues

[ZCMK123]

Hello again all. I have been tackling a quite puzzling issue over the last 2 months or so now.

 

Late last year, I fully rebuilt my 2006 800cc CDI engine thanks to many of the kind users here on this forum. I had not previously had any other issue than starting the vehicle, which was resolved mainly by replacing my burnt up valves. I reinstalled the rebuilt engine, fired it up, and started resolving other issues that popped up. Those issues included needing to lap my high pressure fuel pump surfaces to prevent the car from dying at highway speed, fixing some leaking fuel lines, and pulling the oil pan off due to a bad sealant job from the rebuild. I managed to get the vehicle in a decently stable state so I did what any crazy person would do and I decided it was time for a road trip.

 

I took the smart through a pretty nasty snow/rain storm. It powered through like a champ with its new engine parts, but I didn't realize that my clutch actuator and my transmission were not sealed very well. It had been about 6 to 8 months since I had touched the clutch actuator and the transmission main seal and axle seals were leaky, so I ended up filling both with water.

 

I didn't make it too much further after the storm until it was hit with awful shifting and plenty of clutch actuator related error codes. I managed to get the car to a Walmart parking lot where my girlfriend and I torn apart the actuator, re-greased it, "re-taught" it, and got it back on the road. The plastic gear inside was quite mangled, but it seemed "ok" all things considered.

 

We drove another 80 miles or so until we got another shifting/clutch related issue. We pulled over, stopped, tried to put it back into 1st gear, then upon hitting the accelerator, the car rev'ed up, then lurched forward violently. After that, the 3 bars of death appeared. At that point, we decided to get it trailer-ed back home.

 

Once home, we ordered parts, opened up the transmission to clean it out, ripped open the wiring harness all the way from the ECU to the transmission, verified it was a solid connection and replaced the clutch actuator, connector to the actuator and the connector to the trans rpm sensor. We checked each wire for continuity back to the ECU. Once hooked up, the car still had the 3 bars of death. We tried to reteach the gear selection motor, but the process always initiated slightly, then stopped and failed. So we then removed the gear selection sensor and probed for resistance as detailed on Evilution. It matched up with what he stated value wise, or at least within a 10% variation.

 

We then assumed that it must be the gear selection motor. We have pulled it from the car and hooked up 12 volts to pin 1 and 6. It spins both forward and reverse at similar speeds to other diagnostic videos that I have seen. We also plugged it into the car while the motor dangled, then spun the motor's shaft by hand and watched it's readout in MB Star. The encoder position does indeed change when it is spun by hand. We also moved the gear that the motor interfaces with in the transmission. When we slightly rotate it out of neutral, then hook it back up to the car, it knows that it is not quite aligned, so it moves either forward or back to get the transmission back into neutral...

 

In the MB Star software, all looks ok and within spec as far as we can tell with the exception of the transmission gear position. It states that in software, its position is implausible and unknown. I believe this is why I am unable to teach the transmission. Based on what I know about this engine/transmission, the only way that the car knows what gear it is in outside of teaching, is where the gear selection motor is. I am leaning towards that being defective, but would love some feedback. That or the fact that the only persistent code is C1330.

 

C1330: The CAN signals transmitted from the engine system are implausible.

 

Any ideas on where to look next?

 

TLDR:

Clutch actuator, transmission, and potentially the ECU got wet driving in extreme wet conditions.

Clutch actuator, transmission connectors, and seals were replaced.

C1330 error is present and I am unable to reteach transmission via MB Star.

All wires transmission related have been checked for continuity and the gear position sensor resistances

[Willys]

Have you taken the gear select motor apart to check for corrosion? I have seen a few rusted badly. Do you have another ECU to teach in to see if the signal going to the gear select motor is good? It simply counts revolutions for gear location. The transmission is very simple so to speak. Did you position the gear forks and drum correctly? I expect the transmission operates correctly if you have driven it...? Have you checked all ground pins, yes sounds simple but.....between each eyelet ??? Continuity on all connectors on the wiring harness to see if the wire is damaged/weakened at the crimp? I have had to disect the entire wiring harness searching for damaged wire/continuity issues.....a serious pain in the rear!!!!

[ZCMK123]

Hey Willy, I just went on a road trip and completely missed your message!

 

• I have taken apart the gear selector motor and checked for corrosion. Nothing of note inside was damaged or messed up. All of the original grease was still present, but I cleaned it out and reapplied grease.
• I do not have another ECU, but I am leaning towards that being the culprit personally. I think I will get one on order from MW Smart.
• I am not 100% sure what you mean by the gear fork and drum. I believe I did, but could you explain a bit?
• I have not yet gotten the vehicle to start, so I have not driven it yet.
• I have check all of the wires related to the transmission. All of them are corrosion free and show continuity. I need to recondition the ground wires located next to the SAM because some show corrosion there, but I am not sure if that would be causing the issues.

[ZCMK123]

Update:

 

I got a new ECU in and the imobilizer obviously does not work, but I went to reteach the transmission with the new one, and it still failed to teach. I am starting to think that a ground or something was missed. I guess I will move on to searching and investigating all of the wires again.

 

Question, where are the grounds that should be checked around the car? I know of the one from the transmission to the body as well as the one next to the SAM in the left side "wheel well". Any others?

[LooseLugNuts]

On 6/11/2025 at 3:49 PM, ZCMK123 said:

Question, where are the grounds that should be checked around the car? I know of the one from the transmission to the body as well as the one next to the SAM in the left side "wheel well". Any others?

 

 

if i remember right theres a whole bunch of them in the back near the air filter box/computer thing.....and some in the battery area front passenger floor

[Willys]

IF you took your transmission apart???? Did you rebuild it correctly? The gear select forks I am refering to at the two that guide the syncos(?) cynko(?) Can't spell it it's one of my strong points....lol. The collar that joins different sprockets or gears together to give you the gear selections...? The forks follow a groove on a drum inside the transmission. One of my motorcycle transmissions was similar to this one.

As for wiring, the main issue was where it went over the air scoop or tunnel if I recall correctly. The grounds are a big issue and yes there are many to hunt for. They all look the same, a post with multiple wire loops or eyes stacked on them. The must be dismantled and cleaned between the eyes just to be 100% sure they get the best connection. under the dash, check the firewall. Under the centre tunnel near the shifter. There is also one under the carpet under the driver's seat again iirc. All ground wires are brown, solid brown.
The other thing I found was the crimp for the terminal connection sometimes is too tight and has cut through the wire itself and breaks the connection if bent or wiggled. Check continuity from wire to the tip of the terminals, past the crimp section.

[ZCMK123]

Alrighty, we are solved!!!!

 

As Willy mentioned above, the gear select forks guide the syncros (also don't know how to spell too good) inside the transmission. The smart fortwo transmissions have small cam like machined parts on the end of the fork that interfaces with the gear selector drum, the fancy machined cylinder with the grooves cut out. 

 

My problem was that the lowest cam was pinched in the extended position. I have to assume that when my clutch actuator was filled with water and not working properly, the transmission tried to shift while the clutch was still engaged, which resulted in the gear selector drum trying to force it's way to another gear when it shouldn't have. 

 

Attached I have a pic of what it looked like when I had my fiance take a closer look. The cam will primarily be in it's retracted position, but will occasionally extend out when it goes up and down the "valleys" in the machined gear selector drum. 

 

What we had to do was pull it off, and reshape it back to a usable state. The inner hole should be a cylinder, but since it was messed up, it was an oval shape. It took a bit of gentle persuasion with the vice and sand paper, but we got it back to it's original 8mm inner diameter. Ideally we would have replaced it, but being in the US, parts are hard enough to find as it is. 

 

Long story short, if you have the 3 bars issues and you are unable to teach the transmission, please pull the gear selector motor off and physically try to rotate the gear inside. It should spin with light resistance. If you need a screwdriver or prying tool, something internal is wrong. 

[ZCMK123]

Side view of that gear selector fork cam.

[ZCMK123]

Pic of the gear selector drum.

[Willys]

Glad you found the issue. You could also fine polish the drum track if you are that anal...lol

It's relatively simple transmission once you stare at it long enough....lol.
Yours looks relatively clean inside, mine had some brown oil stuck on the case which needed cleaning off. I took the entire thing apart to check all bearings thinking they may have been an issue also. Not the case.