Service Engine Soon

MX7 · Post by **MX7** » Mon Mar 20, 2023 4:00 am

2005 Z4 w/36,000 miles.

The battery had gone dead (happens often after periods of inactivity). Charged the battery as the inspection is several months overdue and I know after a dead battery I’ll need to drive it a bit to get it inspected.

For several years the exclamation point in the gear symbol shows up periodically. My ind mechanic said it’s a transmission sensor that’s in a PITA location. He said slight corrosion can build up and by moving the (automatic) shifter back and forth several times it should clear the error - which has always seemed to work.

I have a Creator310 code reader.

After battery charging I have a “service engine soon light and the gear symbol. The gear symbol can be extinguished as noted above, but seems to reappear (every time?). The code reader is showing a 299a/EGS error.

Questions - are the two lights related? Is the service light thrown by the 3-month overdue inspection? What can I/should I rule out re the potential ESG error - and what are the likely causes?

Any and all help/suggestions/ideas greatly appreciated!

MX7 · Post by **MX7** » Mon Mar 20, 2023 9:59 pm

Once again - appreciate and ideas or suggestions.

Mike6 · Post by **Mike6** » Wed Mar 22, 2023 6:53 pm

Simple things first. It seems your battery has gone flat a number of times due to inactivity. If you dont keep the battery on a trickle charger if it has periods of non use, I would suggest you probably need a new battery. Do you know how old it is. When batteries start to fail and constant recharging will only hasten that day then all sorts of faults can be thrown so start there .

MX7 · Post by **MX7** » Wed Mar 22, 2023 9:21 pm

Battery is a year old. Yes, the car drains batteries and they need to be recharged when the driving season comes. Since charging it a week or two I’ve been driving the car daily and it starts fine.

I’ve cleared error codes and the exclamation/gear light and service engine soon light appear each time. Codes thrown are the 299a ESG, 3C gearbox switch (P0705) along with power windows, washer pump and KBus/control unit for inst cluster (gateway). My thinking is that I have two issues - the gearbox switch and an ESG issue. Thoughts?

MX7 · Post by **MX7** » Tue Mar 28, 2023 1:35 am

Still hoping for comments and/or suggestions before taking the car to my mechanic…

Rockhopper · Post by **Rockhopper** » Tue Mar 28, 2023 5:06 am

You need to change the position sensor on the gearbox. It'll only get worse and eventually leave you stranded.
As regards the rest of the issues - modern cars are very sensitive to low battery voltage - if your is going flat and you need to recharge it then its probably knackered - batteries don't like being treated like that and you can kill them very quickly.

MX7 · Post by **MX7** » Thu Mar 30, 2023 3:25 am

My mechanic said it’s a PITA to change the switch - he has to drop the transmission because of where it’s located. He also can’t get me in for “a couple of weeks, minimum” which means it will be a month before I get the car back.

I’d like to see if I can do it myself. I’ve searched and have not come across a decent “how to” with photos. Does anyone have experience replacing the switch and/or access to a decent tutorial?

Thanks in advance.

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