Slow startup + SES

[E46tknv]

Hello everyone

Background:08 E90 M3 6Spd 60K Miles

This car is not my daily and seems like the startup is getting worse overtime.
I’ve watched a few cold start videos on YouTube and seems like the car starts after about 1.5-2seconds. Mine seems abnormal and slow at 3 seconds.(will post video when it’s cold again). Timing for startup is not to scale.
Issue:
I was cleaning out the leaves under the hood. Then I started it and obtained a DSC error with SES light. I let it run for about 5 minutes to hopefully remove the errors. Sadly enough, DSC error went away but SES light stayed on.
Voltage:12.15 when off.
Do you think this is a fault SES? Not enough power distributed to the “faulty sensor”? Car ran beautifully on 5/4. It had a similar slow startup.

[codinge90]

Have you scanned the car and pulled codes?

[E46tknv]

Originally Posted by codinge90

Have you scanned the car and pulled codes?

Update:
I let the car cool off for 30min. I started it again and the DSC, yellow brake light and SES light came on. Drove the car to autozone for a diagnosis and looks like it’s telling me I have code p0638. DSC and brake light turned off but SES continues to be on.
P0638 indicates that the throttle actuator control was out of its operating range or had a performance problem, Bank 1 for a predetermined period of time. This is dreadful since I know this is a known issue in this car.

Before I consider replacing this part, could a weak battery be creating all of this? Seems like errors come on/off depending on how long it’s sitting vs driven

[Route 16]

you could let it stay on a battery tender overnight and or unplug the negative let the ECU reset then plug it back in, in the morning

when was the battery last changed? then worse case...replace both throttle actuators

[E46tknv]

Originally Posted by Route 16

you could let it stay on a battery tender overnight and or unplug the negative let the ECU reset then plug it back in, in the morning

when was the battery last changed? then worse case...replace both throttle actuators

Battery is at 12.36

According to carfax and records I have, battery was not replaced. Throttle actuator bank 2 was done 5K miles ago.

Are the symptoms I mentioned lead to a bad throttle actuator?

Update: attempted to remove negative terminal but what a pain in the ass it is so I’ll leave it for another day. While doing so, wiggled it around, tightened the hell out of the terminal and the SES light is gone.

What’s going on....

[Charlievee]

Check the voltage across your battery while the car is running. If it’s under 13.x then your alternator is probably working intermittently and probably needs a new voltage regulator.

Throttle actuator won’t cause a slow start up, the prestart will fail and it won’t crank at all.

[Mvy]

You need a new battery.

[E46tknv]

Battery at 12.05 in the morning. Same slow crank but no warning lights

[Charlievee]

Your alternator is dead if you’re getting 12.05 with the car running.

[E46tknv]

Originally Posted by Charlievee

Your alternator is dead if you’re getting 12.05 with the car running.

Car is not on

[Charlievee]

Turn it on and check the voltage... battery is weak, but it seems you’re getting an intermittent charge. You’re definitely getting weak battery symptoms. It’ll only take a few minutes of driving with a dead alternator till you get a charging error, but it might not come up till your battery charge is really low.
You get all sorts of errors when you’re battery is low including the TA ones.

[E46tknv]

Originally Posted by Charlievee

Turn it on and check the voltage... battery is weak, but it seems you’re getting an intermittent charge. You’re definitely getting weak battery symptoms. It’ll only take a few minutes of driving with a dead alternator till you get a charging error, but it might not come up till your battery charge is really low.
You get all sorts of errors when you’re battery is low including the TA ones.

Looks like I have a reason to buy the Carly app as well considering I have to register the battery after replacing. I’ll keep a look at the voltages because I am not convinced about the TA just yet.

I drove around for 20minutes yesterday with the dsc, brake lift and SES light on at the same time. Power reduced and all.

Got to autozone. Scanned. Turned back on. Lights went off besides SES.

Got back home, turned car off. Turned it back on, SES is off.

[ItsGary]

Originally Posted by E46tknv

Looks like I have a reason to buy the Carly app as well considering I have to register the battery after replacing. I’ll keep a look at the voltages because I am not convinced about the TA just yet.

I drove around for 20minutes yesterday with the dsc, brake lift and SES light on at the same time. Power reduced and all.

Got to autozone. Scanned. Turned back on. Lights went off besides SES.

Got back home, turned car off. Turned it back on, SES is off.

If you have a laptop, I can provide you the necessary links to get ISTA+, that way you just need to buy a cable for $15-25 and save yourself a lot of money.

[E46tknv]

Originally Posted by ItsGary

If you have a laptop, I can provide you the necessary links to get ISTA+, that way you just need to buy a cable for $15-25 and save yourself a lot of money.

Yes I do but already purchased the Carly adapter.



Update:
Morning temperature 50F, Car off= 12.05V

Started vehicle in 77F. Car off=12.15V Car on=14.13
It fired right up without hesitation but of course, SES light with DSC light came on.

Doesnt seem to be a battery would cause these nasty lights to come on.

[E46tknv]

The throttle actuator has lived its life after 63K miles. Thankfully PO replaced bank 2 at 59K miles. Not sure why both sides werent done if your down there.
Heres a video of reference of what shows a bad actuator, after doing enough reading up on the matter. Thank you everyone

Followed by images inside the actuator.

PM me if you want to save money doing the work Ill charge much less then a dealer