Starting Issue with 2001 C5

I have a starting issue with my 2001 C5. The battery is good and the starter has been replaced. When I turn the key to start, there has been a few seconds delay until the starter kicks over. I think this is to allow time to check and cut off lights etc to give max cranking amps to the starter. Last night I moved the key to start and after a few seconds the light went out and the amp meter (on the dash) dropped back but the starter never kicked over. I am starting to suspect a computer module is screwing up. I was about to call for the wrecker this morning and it is now starting.

How do you reset the computer that controls the starting sequence?

I just check the codes and got one that may mean something

40-BCM B0432H

and

99-HVAC- BO348 and V1000H

What does 40-BCM BO432H mean???

If you'll get a straight answer anywhere, it will likely be here but...

AFAIK, the "H" suffix on your code indicates that the trouble code shown is historic, i.e. occurred in the past but is not currently at issue. Not sure how long ago the code was thrown (history is supposedly retained for 40-50 ignition cycles) so just jot it down (so you can share it with the tech if necessary to proceed further) and check again in a few days or after the next starting problem and see what happens. Is it back?

40-BCM refers to the Body Control Module

Next time it happens, run through the codes immediately and see if any are shown as current, i.e. have a "C" suffix. That will be a good starting point

I doubt that B0432 is your culprit but...

B0432 refers to a problem/code thrown by the rear window defogger relay

B0438, it seems, is related to the air conditioning as you might expect from its category assignment.

Not sure on the V1000 other than it's historic

Why do you believe the battery is good? What kind of voltage does it have and how good are the cold cranking amps?

Unhook the battery for more than just a few seconds. Not sure how much that would help as it just allows the computer to reset running parameters, like fuel trim etc.

B0432 Rear Defogger Relay Circuit

B0348 Sunload Temperature Sensor Open

If you mis-typed the V1000H as there are no "V" codes, B1000H means ECU Malfunction.

You need a decision tree to trace the problem and then it does not mean in this case the ECU is bad. It can mean circuit is broken, like a connection is loose, corroded, or a bad ground.

I carried the less than 1 year old battery that is still under a Wallmart 3 year 100% replacement warranty to the store. They checked it with some machine and I think the battery is rated for

555 cranking amps and the reading was over 600. The battery passed all tests.

The battery was removed for about an hour. I reinstalled it last night and it still would not start. This morning I got up and it is starting perfect.

My guess (or wishful thinking) is disconnecting the battery may have forced a reset and maybe this is why it is starting today

Does the BCM module control the starting sequence or is it controlled by the ECM module?

I am beginning to suspect a battery cable to the starter that will pass voltage but craps out under load. These are hard to find.

Needs to be tested under load.

BCM = Body Control module ECM = Engine control module

Why was the starter replaced and who changed it? Most likely your starter cable is not bad, I do suspect a bad connection somewhere.

I worked with a fellow that was replacing his starter every few months. That many starters can't be bad so a new mechanic looked at it and found the timing trigger was mislocated. The starter was trying to start the engine under a very high load. You need a decision tree and someone that knows how to repair your car. The more you mess with it the more connections and wires that can be poorly connected. It is also a good idea to clean and reseal all connectors you work with and the grounds should be cleaned when you start popping codes. Do you have any dielectric grease or cleaner? I like Boeshield T-9 as a cleaner/protectorate but you still need the dielectric grease for a good seal.

Was the connection good. Did you clean the contact points real good between the battery and the cable?

The battery has side terminals and it never entered my mine to clean the cables before connecting. There may be a bad connection somewhere but I don't thing it is at the connection to the side terminals of the battery.

Since it now starts, I plan to take to someone that has a load tester

Which one handles the starting sequence? I read the description of both and it is not very clear which one controls the starting sequence

It failed the same way about four months ago and the tech that checked it said the tests shows the starter was bad. He got the old starter to crank by tapping on it with screw driver.

Sort of like finding a good Doctor.

No and I cannot work on this part of the car from home. Can't get under it without having a lift

Very interesting and Jerry's comment got me to thinking. If you recall from my first posting I have had a delay for some time from when I put the key to START until the the starter does its thing. I have assumed this 3 to 5 second delay is normal for one of the computers to run the starting sequence to check everything before commanding the starter to do its thing. I am still not clear if the BCM controls the starting sequence.

Today the C5 is starting better than ever and there is NO delay in the starting sequence. The starter is working perfect.

My revised (wishful thinking) is two things may have fixed the starting issue. One is the Dad comment that removing the battery forces the computer to reset. I had the battery out of the car for at least an hour taking back to Wallmart for test. The other item is making sure the negative terminal is connected good to the battery. There is little room to get a wrench on the side terminal and something tells me the installer at Wallmart last year may not have made a good connection. When I removed it I was surprised at how easy it was to remove the side terminals. I know my connection was good because I used a small special side terminal wrench that I keep in the car at all times. I picked it up at Wallmart when I purchase the battery in Aug 2011.

A half-assed negative battery terminal connection could cause or contribute to the starting issues.

Stay tuned to see if the fix really works. It is working perfect today.