Suggestions for fixing a 2002 BMW 325ci?

[Goldheart]

This is my first BMW. It was leaking water and driving sluggish.

I have replaced the water pump, fan clutch, and the four O2 sensors.

Water leak seems to be fixed.. phew!

But still sluggish. I had the codes checked at a local AutoZone:

P0154 O2 circuit no activity detected bank 2 sensor 1
P0030 HO2S heater control cicruit bank 1 sensor 1
O0731 gear 1 incorrect ratio

Any suggestions?

Thanks!

[MarcoZandrini]

What brand of O2 sensors did you install? The only brand of O2 sensor you should install is Bosch. You can get them fairly cheaply on Amazon. Why do I ask? The pre-cat sensor for bank 2 (cylinders 4-6) isn't responding.

[dhurley34]

^ To add to Marco's response, the reason why you need to use Bosch is because the O2 sensors read voltage from 0-1v and some brand sensors read backwards. Bosch reports lean to rich as 0-1v. Other brand sensors read lean to rich as 1-0v. So its possible for the DME to receive the opposite signal.

[Goldheart]

What brand of O2 sensors did you install? The only brand of O2 sensor you should install is Bosch. You can get them fairly cheaply on Amazon. Why do I ask? The pre-cat sensor for bank 2 (cylinders 4-6) isn't responding.

Uhh lets see, definitely not Bosch. Kwiksen it looks like.

Here is the Amazon link:

https://www.amazon.com/gp/product/B016BPUO1W

[randy72877]

I'd be more concerned with p0731. That is a transmission code. You are probably experiencing transmission failsafe mode (gear light on and transmission doesn't shift) car accelerates poorly because it's in third or fourth gear all the time. Does the trans shift? Have you checked the trans fluid? There is no dipstick, its done from under the car on a lift or at least 4 jack stands (car must be level and engine running) look up the procedure. gear all the time. Does the trans shift? Have you checked the trans fluid? There is no dipstick, its done from under the car on a lift or at least 4 jack stands (car must be level and engine running). If the transmission is going into failsafe mode it will probably have to be rebuilt or replaced. That is going to cost a significant amount of money. If you are going to auto zone to read codes, I will assume that you are not going to diy it. If this problem started after o2 sensor replacement then hopefully it will be fine with proper o2 sensors. Bosch is oem. Don't use cheap Chinese parts. The sensors you got from amazon are junk. Return them and order bosch. Good luck.

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[MarcoZandrini]

To add to what Randy has written, BMW sourced auto trannies from GM of France and from ZF, a German company. They are completely different trannies. How to tell which is in your car? The GM tranny fluid pan is smooth and flat. The ZF tranny fluid pan is ribbed. They use different filters and different fluids. The tranny computer (EGS) may be different also.

[Goldheart]

I'd be more concerned with p0731. That is a transmission code. You are probably experiencing transmission failsafe mode (gear light on and transmission doesn't shift) car accelerates poorly because it's in third or fourth gear all the time. Does the trans shift? Have you checked the trans fluid? There is no dipstick, its done from under the car on a lift or at least 4 jack stands (car must be level and engine running) look up the procedure. gear all the time. Does the trans shift? Have you checked the trans fluid? There is no dipstick, its done from under the car on a lift or at least 4 jack stands (car must be level and engine running). If the transmission is going into failsafe mode it will probably have to be rebuilt or replaced. That is going to cost a significant amount of money. If you are going to auto zone to read codes, I will assume that you are not going to diy it. If this problem started after o2 sensor replacement then hopefully it will be fine with proper o2 sensors. Bosch is oem. Don't use cheap Chinese parts. The sensors you got from amazon are junk. Return them and order bosch. Good luck.

Sent from my SAMSUNG-SM-G870A using Tapatalk

There doesn't seem to be any issues with shifting. I'm thinking that code is more to do with the sensors than the transmission but I could be wrong.

No, I'm not a great mechanic so I usually have people who know what they are doing work on my vehicles. But I like to know what the issues are and be informed.