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BigBlock434, Chevy Mechanic
Category: Chevy
Satisfied Customers: 291
Experience:  ASE Master certified and 100% General Motors trained in all fields
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2004 Chevy Impala: wont start..the module..replacing..wouldnt start

Resolved Question:

My 2004 Chevy Impala won't start. Before the module was replaced I would wait 9 minutes and the ignition would work. After replacing the module on 9/5 the engine wouldn't start on 9/6.   I waited 20 minutes or so then it started. There were no other problems until today 9/14. It has something to do with security system but I'm getting different answers on how to fix the problem. Some people have stated that a bypass device would fix the problem, but when I spoke to a manufacturer they said their GMBP kit wouldn't solve the problem. Many other Impala owners have written about this problem, but I need some expert advice. The guy who replace the module had warned me that the ignition switch might have to be replaced. Is he right? Any experts with an answer to this common problem?
Submitted: 7 years ago.
Category: Chevy
Expert:  BigBlock434 replied 7 years ago.
I have seen this problem many times. Without a onboard scanner to tell what the system is doing you are just replacing parts in hopes you get the right one. The Body Control Module will cause this problem. The passlock sensor in the ignition lock cylinder will cause this problem. The ignition switch will cause this problem. I have also seen the battery cause this because if the passlock security system voltage falls below 9 volts it will set a theft deterrent code and vehicle won't start. I have replaced more ignition switchs than any other.
Customer: replied 7 years ago.

Does the scanner indicate whether it is the igntion switch or the ignition lock cylinder? The repairman said it was the switch that would need replacement. Is the dealer the only place to get the switch?

Expert:  BigBlock434 replied 7 years ago.
The scanner will tell you the code and will let you monitor live data to see which part of the system is failing. No the dealer is not the only source for parts.
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