'96 318ti Sensors not being read after reset

[mammamlr]

Hello, I have a a 1996 318ti which I have owned since '98. I have always just taken it to the shop, but now that is cost prohibitive. I recently had the wiring harness and sparc plugs replaced, and a couple other things that I can not recall right now, but when we went to get it inspected, there was another fault code related to the same area. The shop replaced what that problem was, but now, the computer will not reset the sensor readings. It just says 'Sensor not Ready', and no one will give us an inspection sticker without those sensors being read. (The car runs great and otherwise passes inpection, but they will not allow the sensor not ready message for more than two sensors, I think)The shop drove the car around with the tool they read the fault codes with, reset the computer while driving multiple times, and each time it woudl being the process of reading the sensors, then just stop. The shop told me that I needed to replace the computer. I am now trying to find the part I need, and when searched, I found there can be 11 button or 18 button computers. How do I find out which one my car has, and is there a place to get instructions for replacing it? This car is my son's now, and he leaves for Army boot camp in August. We really just need to get it inspected so he can use it until then.

Thank you so much for any assistance!

Michelle

[CirrusSR22]

The 11/18 button computer you are finding info on is the OBC or On Board Computer. The OBC is just a little information center telling you things like fuel economy, time, etc. I'm pretty sure they telling you the ECU or Engine Control Unit is bad. The ECU is the brains of the engine, essentially telling it how to run.

I don't think removing and replacing the ECU is hard. It's in a little compartment behind the battery box.

Hopefully someone will chime in on what specific one you need and if it needs to be "coded" or not at a shop. I'm not sure on those specifics.

You can find them for under $100 on www.car-part.com, but again, I'm not sure if any old one will work.

[mammamlr]

Thank you, looking for the right part will be most helpful! I believe you are correct that it is the ECU, and the 11 and 18 buttons respond to the OBD. I will do some more searching!

Have a great week!

M

[jonchino]

What does "not ready" mean?
Your vehicle's OBD system collects data while you are driving and uses it later to determine if your vehicle passes the OBD emissions test. In some cases, the computer cannot collect enough data and indicates it is "not ready" to provide test results. This can occur if repair work was performed or the battery was disconnected recently. It normally takes at least a week of combined highway and city driving for the computer to complete its systems check and be "ready" for the OBD test.

[mammamlr]

Thank you for your reply, I apologize that I forgot to mention that we have been trying to get this resolved for about a month, and the shop kept giving us 'driving patterns' to complete. Usually some combonation of stop and go with high speed (highway) driving, totally at least 50 miles each time. Is there a 'next thing' to look at in a process of elimination?

I appreciate the quick responses from you all! This site is wonderful!

M