[scotty02uk]

Here is a quick post on an issue i have had recently, and its conclusion. My car randomely went into "limp mode" and the red cog of death appeared, could not change gear and seemed like it was stuck in 3rd/4th. Also the ABS, brake, traction control light were all illuminated. It was working fine, i parked for 5 mins, came back, started her up, and heard a "clonk" and the lights came then illuminated. I used a cheapo scanner and found 2 codes, P0600 and P0369. the 1st code meant no communication with some ECU , the second was the camshaft position sensor (exhaust). I replaced this myself with help on this forum and P0369 code disappeared, the P0600 remained. Later on i went to turn on the car and it wouldnt start!, headlights flashed, and all lights worked inside etc and radio. Also made a weird fast clicking sound. After more research this pointed to the battery, checked it in the boot and saw it was the original and replaced it - car now starts (however still have P0600 error and limp mode). I checked all the fuses - in the glove box and in the E-box under the hood by the ECUs - none blown. It is also a good idea to check the relays.Got a mate to investigate with some better diagnostic software and he found he could communicate with certain ECU's but not the EGS/TCM (transmission ecu). Sent this off to a company to have it checked/refurbished and they said it was fine!, very confused at this point. Decided to get a second opinion. Took it to chris plummer in aldershot, he said he couldnt communicate with the transmission ECU either. 3 days later this was replaced and the car is back to normal, although the ECU did cost £700 including VAT. All codes now gone, and car drives like new!. Hopefully others will find this useful, as there dosnt seem to be many posts like this with a conclusion to the problem.:thumbsup:

 

[RuS-uk]

ahhh man i have this problem!! did you buy a new trans ecu? can you not get a second hand trans ecu or are they "locked" to each particular car??
please help thanks! russ

 

[scotty02uk]

Good question. I got a new one and on my bill I was also charged a programming fee, however I have heard that some people have got them off eBay , or down the scrappy, installed them and worked. I'd make sure the serial numbers wereasclose as possible and year etc

 

[Hector45]

Thanks for your input.

 

[CHEFSBOSS]

Holy thread revival. I was doing some research on another E46 project and I ran across this thread, it's nice to have some that post actual fixes.. I wanted to add that I have some good experience with what happened to the OP.., and lemme expand san say why it happened to him that way, and hopefully future searchers or knowledge seekers in general will see, as many a regular mechanic (as well as some BMW techs) may not be so in tune to this particular issue.

The CPS aside ( I think unrelated)... the battery was on its way out in the OP's E46.., and what happens, in a nutshell, is the battery makes up whatever deficit...
Say you're driving along, and radio on, ac on, and slam on the brakes.., for a few seconds, you're car is using 14 volts..., but for those same seconds, the car is only charging 13 volts... well, in a properly functioning sytem, that 1 volt shortage is sucked from the battery, and not even noticed... then a few seconds later, the "missing" volt is replaced,.. and all is well.., but a weakening battery can't keep up...., still over the 12. volts that will set of the battery warning light, and just enough to start the car (for a while) but not enough to keep up with the modules on a running "module heavy" E46...., and that's when weird things start to happen. Especially with automatics, and the EGS (tcu) (a whole extra unplanned module, and set of powered solenoids etc..)

And very quite likely, you will get thrown into safe mode, with the 3 lights warning.... I would guess that 85% of FAIL SAFE issues are initially caused by voltage fluctations / defecits like that)
And in the rare cases,.., the EGS (a module--basically like a hard drive) can occasionally short out, as a rush of power from the unfused CAN BUS, or other source can actuall wipe the coding right off the drive...,..or at least enough of it so it doesn't make sense.

Many times you can get lucky, and reflash the module, (The main coding is stored on the DME and just copied to (or flashed) back to the module,,,and it will be fine.., but occasionally, a resistor or internal thing will burn out, and you'll need a new module. (Unless you're technically inclined in transistors)

the reflash can actually be done with proper obtainable software right in your garage now..., shhh don't tell the dealer..!! But, also, a used Ebay EGS (same as TCU), as long as its for the same trans (It will have the same code) will do the trick.


Just thought I'd add, as the OP was kind enough to share his fix...

And for those Automatic riders out there, ... don't screw around, just replace the battery every couple of years..., there's a better chance of safe mode happening before the battery indicator light., and a great many unknowing shops will swear you need a new transmission, before they ever think the battery is at fault)... only on that 1st test drive,, when they end up in safe mode again, will they eventually get to the battery or charging system... (and even that may appear to be working fine for a while)

(Do the OBC hidden voltage test on the dash whenever you want to chwck your voltage and make that the 1st check after a fail safe)
Good luck... !... now,.. back to my research.., anyone got an EGS man or coding file?

 

[angel928]

Hmmm... I've got an '01 330i with about 118,000miles, and have recently been having the trans issues with the "red cog of death". I typically happens at the end of a decent length ride, of at least 30mins. It typically begins following a complete stop where the trans will 'slip' and soon thereafter the red cog will appear. Mine is not associated with other warning lights excpet the Check Engine which has been on for a while due to a torn air intake boot. I will soon be able to use a BMW specific scanner which will hopefully give me more infor than a general OBD-II scanner. I guess best case would be a battery problem. I wasn't the original owner, so I'm not sure how old the battery is. Hope it isn't the EGS but I'll start looking on Ebaay just in case.

thanks to all for the input.

 

[scotty02uk]

You should hope it is the egs, as this sounds more mechanical with the slipping. I'd def get codes read

 

[angel928]

What is interesting is that the slipping is present when it starts to happen and before the actual red cog indicator comes on, but once the indicator appears it simply feels like it is starting out in 3rd gear with little torque. I sure hope it isn't the actual trans..

 

[scotty02uk]

So its gone into safe mode then?

 

[angel928]

Yes. But leave it be for a day and it'll be alright again sometimes for more than a day but then the problem arises again. I'm somewhat familiar with trans problems having had a VW trans let go slowly. Somewhat a different animal I know, but when it slips it doesn't get better. This is different, which is why I'm holding out hope for an electronic isssue instead

 

[Pwn Shop]

I have the exact same problem as Angel, no other lights coming on but the red cog of death, after about a 30 min ride or so, and it is stuck in approx 3rd gear... Very anxious to hear about this issue as it just started this week. After letting it cool off for an hour or two it goes away until the trans gets back up to temp after 30 min ride again...

 

[Pwn Shop]

Update: I went to get my battery checked, as I have heard that low voltage can cause the trans can go into limp mode. The battery tested bad, so I happily shelled out 150 bucks for a new one, thinking it would fix the trans problem. I replaced the battery, and the problem is still there, now it is always in limp mode, even when i first start the car up after it is cool. Also, the check engine light came on just before replacing the battery. Alternator was tested, good. I am off to get the code pulled tomorrow and see what it says.

 

[Pwn Shop]

Alright pulled codes P0700 and P0734 = trans control unit and 4th gear ratio incorrect. Resetting the light the car drove fine for 15 min then the red cog of death reappeared, and the Check Engine back on, pulled the same two codes again. So, definitely not the battery as the problem duplicated itself after battery replacement. Any guidance please!?

 

[angel928]

Hmmm... I've got an '01 330i with about 118,000miles, and have recently been having the trans issues with the "red cog of death". I typically happens at the end of a decent length ride, of at least 30mins. It typically begins following a complete stop where the trans will 'slip' and soon thereafter the red cog will appear. Mine is not associated with other warning lights excpet the Check Engine which has been on for a while due to a torn air intake boot. I will soon be able to use a BMW specific scanner which will hopefully give me more infor than a general OBD-II scanner. I guess best case would be a battery problem. I wasn't the original owner, so I'm not sure how old the battery is. Hope it isn't the EGS but I'll start looking on Ebaay just in case.

thanks to all for the input.

UPDATE: above is how my story started. Yesterday I replaced the torn intake boot figuring it might perhaps be leaking more than previously and perhaps contributing to my "limp home" trans issue. This morning I drove it 32 miles to work and all ok with the trans, after not having driven it for about 2 weeks. Once I got here decided to scan it again and lo and behold I discover I have two other codes besides P0174 System too Lean (I'm guessing that one will clear itself now after I drive a bit more). I should have checked this before and saved myself headache and time :banghead:; I've got P0344 Camshaft Pos Sensor Circuit Intermittent and P0505 Idle Control System Malfunction which I believe is related to P0344. So it appears the Cam Position sensor is the culprit in my case. I'll report back once I replace it.

 

[angel928]

Well I thought I was home free with my finding that the cam sensor(s) were faulty and that was behind my trans problem but I wasn't so lucky. Changed out the sensors and I was ok for one day but today again I got the "death cog" while driving home. At least now the car doesn't stall out when the trans acts up. Prior to clearing the codes I had a pending code which read incorrect gear ratio 3. Sorry I don't have the number at the moment. I guess at this point I'm back to thinking it is the TCM. Isn't there any outfit state side that can recondition them or check them out - anyone know??.

 

[angel928]

Installing used TCM

Another followup; snagged a used TCM on ebay. I pulled mine and compared numbers to make sure it matched up. Various numbers one of which matched. Verified with seller that was the one that needed to match up. Used unit due to arrive today. Will install as soon as it stops raining. HOpe to have a positive report after that.

 

[jcs325iT]

Another followup; snagged a used TCM on ebay. I pulled mine and compared numbers to make sure it matched up. Various numbers one of which matched. Verified with seller that was the one that needed to match up. Used unit due to arrive today. Will install as soon as it stops raining. HOpe to have a positive report after that.

Any update..?

 

[angel928]

Disappointing, but I still have the problem. It's usually ok back & forth on my 45min hwy commute, but if I decide to drive it more in the afternoon it tends to slip and get stuck in 3rd, though last time I did an extra hour roundtrip to my daughter's dance class and it was fine. Go figure... I'm at a loss for the moment.

 

[jcs325iT]

Disappointing, but I still have the problem. It's usually ok back & forth on my 45min hwy commute, but if I decide to drive it more in the afternoon it tends to slip and get stuck in 3rd, though last time I did an extra hour roundtrip to my daughter's dance class and it was fine. Go figure... I'm at a loss for the moment.

Well, my car started having a funky problem while going down the road, the throttle would simply die off---not stall, just go to idle--while my foot never moved from it's position. I apply a little more pressure to the pedal and the signal is resumed. It would do it again, off and on, no regularity.....couple of times the gear light would come on but the car wasn't in limp mode, and would shift in sport mode or regular without issue. Otherwise, the car runs fine.

I have access to a BMW GT1 diag system and the car had 3 BMW codes...a 97 for CAN (buss) brake signal to the EGS, a 78 (DME) for accel and brake pedals and 27 (DME) for brake signal. Hmm....if it comes back, we'll reprogram the DME next weekend.

I had read CHEFBOSS's explaination about current spikes and low battery voltage/aged batteries and how sectors of data could potentially get wiped from the DME or EGS, so we decided to wipe and re-program the EGS. Did that last night.

Drove it about 15-20 miles last night after the reprog, 10 more to work this morning, no issues so far. We'll see......

 

[angel928]

TCM update

Quick review. Thought it was TCM, but got used and still in same boat... but. Recently pulled a new trouble code not there previously 0720 ( output speed sensor) which is on the trans. One of the syptoms listed on a search for this code is SHIFTING PROBLEMS. So maybe I'll have a bit of good luck on this. Part is $52 so definitely worth a try. Otherwise I'll likely get rid of it.