[madmunky]

I've got a strange issue which has started recently, the car works fine when driving normally but if you push the car to the red line and make it shift gear its feels like a misfire kind of jolt as its changes gear. normal gear changes are fine when the revs are not at the limit, has anyone got any ideas what might cause the issue.

If there was a clutch slipping i wouldn't have expected the jolt that happens and also if I push the car and manually shift around 5000 rpm the issue doesn't happen.

I've also brought carly for my iphone and done a scan which is not showing any errors being reported

 

[HerbP]

Not not your history or ownership of your car, it sounds like your battery is weak. Try charging your battery to see if these problems will go away. The battery in our cars needs to be charged on a monthly basis, especially if you make a lot of short trips.

 

[madmunky]

I've had the car around 4 years, alternator was recently replaced and battery is a few year old but I don't get any issues with the car starting so I'm not sure the battery is the issue. The only thing I can think is it feels like it's hitting and rev limiter and not switch gear fast enough which is why when I manually do it I'm not right at the Rev limit so don't get the jolt.

 

[HerbP]

Measure your voltage at the jump terminal with the headlights on. If your voltage is less than 12 volts, you have probably found your problem. It is possible that your fluid is a little low, as it can cause harsh shifts at any time. Checking the tranny level is an adventure in itself, if you have never done this.

 

[madmunky]

Thanks HerbP,

I'll take a look, I think the issue is a late shift at the rev limit as I watched it today as I was testing and normally as soon as it hits the red line it shifts up a gear but I notice it went into the red jolted then changed gear, I hope its just the transmission fluid so will get this changed/checked.

If anyone else has any ideas feel free to chip in

 

[madmunky]

I've been out and tested the battery which shows 14v so I expect that is fine but I am getting some strange error being flagged up like today I've had 5EC0 and A3AA. I've cleared them down and they have not come back so I'm kind of getting the feeling I may have an alternator issue. What is the best way to check the alternator on the 645 seeing how sensitive it is to voltage drops checking it on idle it seems fine.

I dont tend to do short trips in the car each trip is normally around 50 miles so I dont think its a issue with the battery not holding/getting charge.

 

[Doug Huffman]

BMW's will not fully charge a properly registered AGM battery. An AGM battery is instantly marginally measurably damaged by overcharge, chronic overcharge will deplete the electrolyte in short order. One ampere-hour over charge electrolyzes 0.335 grams of electrolyte water to gas.

 

[HerbP]

I've been out and tested the battery which shows 14v so I expect that is fine but I am getting some strange error being flagged up like today I've had 5EC0 and A3AA. I've cleared them down and they have not come back so I'm kind of getting the feeling I may have an alternator issue. What is the best way to check the alternator on the 645 seeing how sensitive it is to voltage drops checking it on idle it seems fine.

I dont tend to do short trips in the car each trip is normally around 50 miles so I dont think its a issue with the battery not holding/getting charge.

If you are reading 14 volts, that is from the alternator. Check the battery at the jump terminal with the lights on, & the engine off.. It should be above 12 volts. The 5EC0 is a steering angle sensor code. This is usually associated with a low voltage problem from the battery.

 

[madmunky]

So check the car before leaving for work, battery was @ 12.2v with the lights on.

got 15 miles down the road and the car died, its throwing up all kinds of errors.

Ended up having to get it dropped of at a BMW Specialist as when I cleared the codes it drove another few miles then came back but they cant find the root of the issue, they said cause everything goes via the crankshaft sensor so they are going to try and change that as apparently BMW now supply a modified one with a wiring loom? they think its like the car is losing signal to the sensor then flagging up all the errors

Getting to the point of just not having any trust in the car

 

[HerbP]

Sounds like it could be a crankshaft sensor based on those codes.

 

[buschris]

can't wait to see the outcome, I'm having a hell of a time with my car after my coolant pipe repair. I'm thinking battery/alternator or crank sensor as well.
*update* my issue was loose green plug in ECU box. <facepalm>

 

[madmunky]

Garage has called and said I can pick the car up, they have replaced the crankshaft sensor and re-solder some joints on one of the modules (BCM I think, I will check when I pick it up) the problem is they are not sure if the issue is resolved or not as they have cleared the codes and left the car running and they have not reoccurred but I could clear the issue and it would go away for a couple of miles and they have not driven the car.

What I want to do is because I have a OBD Adapter is enable some logging so when/if the issue happens again I can try get a better understand of some values the ECU's are seeing.

I know I can log out the battery voltage which is one thing I want to still check but is it possible to log the crankshaft sensor value as I cant see a PID for this? I have Carly and OBDFusion if there is any other recommended software let me know and ill try that and also what values are worth logging that may help.

 

[madmunky]

Got the car back and it made it home (isnt very far only a few miles) Im not sure I trust it yet so the 130 mile trip tomorrow should give me a good idea. It turns out they removed and cleaned the IVM unit and doing some searching online i found this post

http://www.bimmerfest.com/forums/showthread.php?t=850578

It sounds very similar to my issues and so I have ordered a replacement IVM unit from ebay as I cant seem to find a new one as hopefully at least this will let me be able to test if its that unit. Figures crossed i wont need it and the problem is resolved by them removing the IVM and cleaning it up but least I have a spare now.

buschris: This wouldn't be the same module you had the plug come out of would it?

 

[buschris]

not sure, but perhaps I should check my board and see if the traces cracked and if so, repair it with some mad soldering skills!

 

[madmunky]

Thanks i thought because in your thread you put

Problem solved, one of the green plugs in the ECU box had come unplugged

the issue may be the same box, is your issues now resolved?

 

[buschris]

part of it, yes. My transmission still acting funky even with new solenoids, adapter seal and zip kit.

 

[HerbP]

Got the car back and it made it home (isnt very far only a few miles) Im not sure I trust it yet so the 130 mile trip tomorrow should give me a good idea. It turns out they removed and cleaned the IVM unit and doing some searching online i found this post

http://www.bimmerfest.com/forums/showthread.php?t=850578

It sounds very similar to my issues and so I have ordered a replacement IVM unit from ebay as I cant seem to find a new one as hopefully at least this will let me be able to test if its that unit. Figures crossed i wont need it and the problem is resolved by them removing the IVM and cleaning it up but least I have a spare now.

buschris: This wouldn't be the same module you had the plug come out of would it?

Did you purchase a new or used IVM. This should be available at any BMW dealer, or Online BMW store. Around 100.00 for a new one.

 

[FredoinSF]

Might be too late but bought IVM from FCP Euro. Very happy with them.

Could be IVM, but only real symptom of failed IVM I can recall reading is a no start condition, whereas your symptoms are on the go. Hope it works for you

 

[madmunky]

Did you purchase a new or used IVM. This should be available at
any BMW dealer, or Online BMW store. Around 100.00 for a new one.

Unfortunately it was used as I didn't realize I could get new still so if it goes wrong again I will
replace it with my used one and if the issues are resolved ill order a new one from BMW.

Could be IVM, but only real symptom of failed IVM I can recall reading is a
no start condition, whereas your symptoms are on the go. Hope it works for you

The reason I think it maybe the IVM as all the codes I get are sensors the IVM controls power
too and it seems like the IVM is cutting power causing all the sensor to got report values back
to the ECU and then it throws up all these codes, looking at the image woodnthings8 posted it
shows almost all the sensor mine flagged up when it does go wrong.

Anyways it made it into work today so thats 60 miles completed, lets see if it makes it the 60 miles home, I will keep the thread updated

 

[FredoinSF]

Makes sense, interested in outcome so looking fwd to updates. Hope your woes are over.