BMW Repair Questions? Ask a Mechanic for Answers ASAP
Thank you for the VIN. I was able to find information on these codes for a Z3. The 1189 and 1188 relate to a fuel control problem or unmetered air leak. In most cases this seems to be a cracked intake boot or problem with the crank case breather system.
The best thing to do to diagnose this would be to have a smoke test performed. This will show any air leaks that are present and this should be corrected first as this is the most common cause of this fault. The second most common is that this could be a problem with the mass air flow sensor. The dealer could perform both the smoke test and test fit a new mass air flow sensor and then drive the vehicle to verify the effectiveness of the repair.
This way you will only have to pay for the part if this is the mass air flow sensor is bad. If you do find a leak in the intake boots then it would be a good idea to replace those items and have the codes cleared and see what may come back.
I hope this information is helpful. Please accept and I wish you the best with your repair. Thank you.