johnnyblades

Have a problem

32 posts in this topic

I am having a bit of trouble with my smart, I was getting the 3 bars and the car would not go into any gears. I followed the steps to grease the actuator as per the video posted. Went through the gears changes to get everything lubed and had the 3 bars disappear. Thought I was going to get away easy, went for a short test drive and when I shifted up into 5 gears I had the downshift arrow appear. I gave it more gas to up the rpms and the 3 bars came up again. I pulled over to the side of the road, shut the car off waited a few min and restarted and the bars disappeared. I came back home and put it back up on ramps and tried to look to see if there was any breaks in the wiring coming from the actuator and the transmission. I didn't see anything that looked chafed and was wondering what to look for next.

Share this post


Link to post
Share on other sites

Petrol or diesel 450?

 

The 450 suffers chafing on transmission part of engine wiring harness in the following areas:

1) Where harness chafes against sharp edge on intercooler support cradle. 

2) Near connector to clutch actuator. End of outer protective sleeve cuts into the thinner of the six cables.

 

Both areas can only be seen from below.

 

Best preventative cure is spending quality time under your Smart inspecting wiring and improving on the way it is held in place plus adding electrical tape  or self amalgamating tape here and there. 

 

Chafed wiring is best repaired by soldering and splicing in extra cable if required.  

You may find the copper strands have gone all black so no solder will wet. Use hydrochloric acid solution (I use brick cleaner containing 10% HCL) to turn black oxidised copper bright again. 

 

Also sometimes causing trouble is angle sensor for shift drum. Water enters sensor internals. Cause is build up of corrosion on seal area. Replacing sensor without first cleaning seal area and greasing seal area is not a long lasting fix.

 

 

1 person likes this

Share this post


Link to post
Share on other sites

Mine is a diesel, I noticed that the bars came back when I went over 60km, could a cracked reluctor ring cause the 3 bars? I was trying to see where the wires come in contact with the inter cooler guard but am not sure where to look.

Share this post


Link to post
Share on other sites

Chafing in way of contact with cradle happens in general when harness is poorly clamped.

Most common area is near connector for clutch actuator.

 

Split abs ring does not cause transmission trouble. 

 

Get under your Smart with a good bright  torch. 

Share this post


Link to post
Share on other sites

Found no chafes in the harness, when I went to start the car you can hear the actuator trying to select a gear, the dash showed it being in 6th. I moved the shifter back and forth a few times then it went to neutral then the 3 bars. Could the actuator be faulty? Or the gear selector? 

Share this post


Link to post
Share on other sites

Also in a previous post you mentioned angle sensor, where is it located? I looked on the fq sites under sensors and they didn't show it in the picture of the gear sensors.

Share this post


Link to post
Share on other sites

Shift drum angle sensor = gear position sensor.  Sits at left side of shift drum, left side of transmission.  Held on with two M6 Torx headed screws.

Share this post


Link to post
Share on other sites

Strange it was indicating being in 6th gear when stationary. I've never seen that before. Something obviously is wrong. Is your Smart in a dry or wet part of the world?  Reason I ask is only a faulty gear position sensor can possibly make engine control unit believe transmission is in 6th. Good chance there is corrosion on seal area for gear position sensor if this Smart has been exposed to a wet climate since birth. 

Share this post


Link to post
Share on other sites

I followed the wires from the connections up to the inter cooler, mine doesn't contact the shroud. I couldn't get the connector to release or I would have pulled it all the way into the engine bay. I am not fortunate enough to have a garage so I have the car on ramps in my drive way. I was under there for a couple of hours till the rain started. 

Share this post


Link to post
Share on other sites

I'm up in northern Ontario. The weather has been pretty damp lately. Expecting more rain and snow this week.

Share this post


Link to post
Share on other sites

Might also be corrosion from all the salt/brine MTO covers our roads with. This new brine solution that is being used is brutal as it sticks then kick start the rusting process. 

Share this post


Link to post
Share on other sites

I have owned the car for 6 years, never had a problem in the winter before. I have a parts car in my backyard but it's kind of buried in the snow. I was supposed to dismantle it this summer but had a Reno project that took a bit longer than expected and didn't get to it. I am going to try if possible to get it to a friends garage with a lift to get the tire and wheel shroud off and get a better look at the connections for the actuator and gear selector.

Share this post


Link to post
Share on other sites

I read through the whole "woo 3 bars" post and watched the short vids with it. Hope once I get the car on a lift I can get the connectors off and pull the whole harness out and check all the sensors

Share this post


Link to post
Share on other sites

I read that in some places they are adding beet juice to the brine mixture to increase it's ability to stick. The other interesting thing to note is that around the time we started using brine mix new cars started shipping with cabin air filters. A coincidence or perhaps a way to reduce respiratory issues caused by inhaling this stuff.

 

Oh and the moose appear to like this new road coating,

 

 

44238099001_3993397156001_21360826-source-moosevideo-vs.jpg

Share this post


Link to post
Share on other sites

It wasn't to cold out today -10 to -15 so used a hairdryer to warm up the connectors and pulled all the wiring up into the engine bay. All wires were fine and the connectors showed no corrosion at all. Waiting for a gear sensor from the local smart dealer. Expecting 10 to 15 cm of snow starting on Tuesday! So hoping it comes in on Monday! This had better work or will have a large fire in my driveway when I burn the car!! ( maybe)

Share this post


Link to post
Share on other sites

I would have removed gear position sensor first to confirm if indeed it is faulty. It is only a 5k pot meter so easy to test. 

Share this post


Link to post
Share on other sites

Remove and inspect sensor. 

 

DrumRotationsSensor.jpg

 

Above sensor is damaged due to water ingress. Test using multimeter. Sensor is a 5k pot meter. Can't remember whether liniar or logarithmic. Connect to wiper signal and either of the other two one after the other. Wiper signal should be smooth without jumps when turning sensor. 

 

Edited by tolsen

Share this post


Link to post
Share on other sites

Update time.. So I had changed the angle sensor to see if the would solve the problem, guess what.. It didn't. So chatted with some of the mechanics at work and decide to put the wiring harness out again. So this morning brought it into the nice warm garage, put it up on stands and took everything out for another look. There was no wear in the usual spots mentioned in all previous articles, then we found it!!!! So about a half inch up from one of the connectors going through the inter cooler scoop we saw a tiny hole were some had used a probe to test the wire. Repaired it and sealed no no water will ever get at it again. I must say trying to get the connections off in the scoop area are a bloody nightmare, the tiny metal clip that they have holding it is a torture device put there to drive you insane!! I have to just clear the codes and go for a drive on the lovely roads up here to see. Fingers are crossed. 

Share this post


Link to post
Share on other sites

So how did it go have you managed to fix your random shifting issue or was the pierced wire you fixed preventative measure to be appreciated later ? I have been driven around the bend and back by mine clicking through gears on startup but I guess the saving grace is that I have been able to drive it with no other issues . Anxiously awaiting your next update.

Share this post


Link to post
Share on other sites

So my fix didn't take unfortunately, as soon as I get up to 50 kms the bars come back. I was still able to drive it to work until last night. As soon as I started it up the bars showed and was unable to get any gears. I pushed it into the work garage. I put it up on stands today plugged in the code reader and got a new code p715. Does anyone know how to fix this one? The p702 is gone!! I await your input. 

Share this post


Link to post
Share on other sites

What you should do is test your transmission wiring harness and carry out proper long lasting repairs. 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now

    Chatbox
    You don't have permission to chat.
    Load More