Chevy Malibu Theft Light And Crank Position Variance Learn

Problem with my 2001 Chevy Malibu V6.
Repairs done prior = IGNITION SWITCH REPLACED AND TUNE UP. NEW BATTERY, NEW ALTERNATOR AND CHANGED COOLANT PUMP. Question = I have an 2001 Chevy Malibu i turn the key but the fuel pump doesn't always kick on i just put new fuel pump sending unit and pick up in it. i am still having same problem. Try to start and it cranks but wont start. After a while i might get lucky and the fuel pump kicks on and it starts. Once it starts its fine till i try to start it again. Can some on please help. Thanks

Answer:
Assuming you dont have a security or theft light on, then this sounds like it may be a faulty fuel pump relay. This relay is in the under hood fuse box. Swap it out with another relay if the same type in that fuse box. Have also had faulty fuse boxes themselves. Poor connection inside can cause low voltage to the fuel pump. Would need to have a test light on the fuel pump power feed circuit at the rear underside of the car when it is acting up to see if you have 12 volts. If you do, then it is a ground problem.

Question:
After changing the crankshaft position sensor a code stating that the crankshaft position variation was not learned. What does mean and what do i have to do to clear this code so that the engine light will go off? A code saying that the catalyst efficiency below threshold bank 1. What does this mean and what do i have to do to clear this code so that the engine light will go off. Work done to repair this problem = the crankshaft position sensor and harmonic balancer has been changed.

Answer:
The crank position variance relearn needs to be done with a scanner. The code cannot be cleared until this procedure is done. This needs to be done because of the crank sensor replacement. Catalyst threshold can be caused either by a faulty Oxygen sensor, or a faulty catalytic converter. Reading live sensor data and testing of the oxygen sensor would be needed to determine which one is faulty.

Sorry. I to had that same problem. It was the security theft switch on the car. It goes out and it wont let the car start. But sometimes it does. I did a lot of work to it before I found out on-line what it could be. I forgot how exactly how they fixed it.
But I do know you have to have the car on and rig the switch to operate on, all the time. You can go to the dealer and have them do it for a lot of cash. 2001 were a rip off, a bad line of cars. Your auto-theft wont work anymore but your car will. You can always buy a car alarm.