BMW z3 2000 model . How do I cancel the exhaust emission light after replacing a torn intake hose.

It would appear that there is a crack in the exhaust manifold or a faulty manifold gasket. The fault light may be the ECM warning of a "faulty" O2 sensor which is the one after the cat converter as the ECM reads the differences in voltages between the front sensor ( HO2S) and the O2 sensor. That is how it knows of such things as faulty cat converter, manifold leaks ,manifold leaks etc.
If it is not under warranty find an accredited shop that specialises in you make of car for a second opinion, but if still covered by warranty complain very loudly to the manufacturer about the service dealer.

Go to a big autoparts store and have them check the engine codes

• Replace spark plugs
  

• Replace rotor
  

• Check distributor cap (replace if necessary)
  

• Check timing (adjust if necessary)
  

• Check ignition wires (replace if necessary)
  

• Check ignition performance (firing voltage and ignition patterns)
  

• Check idle speed (adjust if necessary)
  

• Check choke (carbureted engines)
  

• Clean fuel injectors
  

• Check compression and/or power balance (identifies bad fuel injectors as well as compression problems)
  

• Check manifold intake vacuum (reveals exhaust restrictions)
  

• Check battery/charging voltage
  

• Check exhaust emissions (verifies fuel mixture, ignition performance and emissions performance)
  

• Check vehicle computer for trouble codes
  

• Install new air filter
  

• Replace fuel filter
  

• Replace PCV valve
  

• Check all emission controls (EGR valve, air pump, etc.)
  

• Check all vital fluid levels (engine oil, transmission fluid, coolant, brakes, power steering)
  

• Check belts and hoses
  

• Check safety items such as lights, wipers, tires (including inflation pressure), horn, etc.
  
  

Have a shop scan for the codes this will point you in the right direction of what is wrong.They usually do it for free.It only takes ten minutes.

This means that your car has registered a problem with the exhaust emission. This generally means that your car is either running too rich or too lean as a consequence of another problem. This can be caused by a large number of faults from an air leak in the intake system to a hole in the exhaust system or even an oxigen sensor problem.

This particular car is famous for a rubber crankcase breather hose at the back of the block persishing letting in unmetered air. The hose runs from the back of the rocker cover to a small disc shaped diaphragm on the underside of the inlet manifold. This diapragm is also prone to failure and sometimes can be identified by a hissing noise when the engine is switched off.

Failing this, you will have to have the engine management fault codes read to narrow down the problem. This engine is generally inexpensive to repair due to it's good reliability.

Just got the car read on the machine and there are two faults, it may be the exhuast, so they got to check the exhaust system or it may be the 02 sensor.

Hope help with this (remember rated ths help). Good luck.

SECTION 303-08: Engine Emission Control 1999 Cougar Workshop Manual REMOVAL AND INSTALLATION Exhaust Gas Recirculation (EGR) Valve Removal

1. Remove the air cleaner outlet tube.
   1. Disconnect the intake air bypass hose.
   1. Disconnect the positive crankcase ventilation hoses.
   1. Remove the air cleaner outlet tube.

1. Disconnect the tube from the exhaust gas recirculation valve.

1. Remove the exhaust gas recirculation valve.
   • Disconnect the vacuum hose.

Installation

1. CAUTION: When cleaning the gasket faces, do not allow debris to enter the intake manifold or exhaust gas recirculation valve.
   Clean the gasket faces of the intake manifold and exhaust gas recirculation valve.

1. Install a new exhaust gas recirculation valve gasket.

1. Position the EGR valve and install the bolts.
   • Install the vacuum hose.

1. Connect the EGR tube.

1. Install the idle air control valve. For additional information, refer to Section 303-14A . For additional information, refer to Section 303-14B .

HAVE IT TESTED FOR TROUBLE CODES THAT IS THE KEY TO FIND THE PROBLEM.

The Exhaust Emission Light can come on if the car is driven slowly over short distances.It will not happen on cars driven at speed. A short trip of ten miles at over 3000 revs should reset the warning light,although it may not go out for a couple of days after you have tried it . Hope this helps and saves a bill at the local dealer. JK

daves944 is dead right . you could try thrashing the ars of it just befor it go in again most mot places will do it for you if you ask them ,, but be warned if it go bang witch it should not its not ther fault,,,, it has worked for me more then once

this may be your egr valve, does it want to stall when its ticking over.