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intermittent not starting by a 2012 Impala LT fleet

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18K views 12 replies 6 participants last post by  coloradofjr  
#1 ·
I have a 2012 LT fleet with 305,xxx miles. Over a year ago, I began to have issues with my Impala not starting. I would turn the key to the start position and lights would go out but nothing would happen - no clicking -nothing. If I tried a few times then the Impala would start as normal. The starter turned over normally, not showing symptoms of a dying battery.

Having had similar issues with my old Chevy pickup and having solved the problem by replacing the ignition switch, that was the first thing I replaced. The issue went away for a few months and started to occur more frequently. Some times I would get the message to "Service Security System". It got progressively worse, so I change the ignition switch again, this time with an AC Delco part. This did not help.

I bought a higher end scan tool that allowed me to pull error codes from individual control modules in the car. I found codes:
  • P0513 - Engine control module -Immobilizer key incorrect ( I am still using the same originals keys/fobs I got when I purchased it in 2013)
  • B3935-57 - Theft Deterrent Module - Transponder authentication
  • B3060-00 - Theft Deterrent Module - Unprogrammed transponder identification code received
  • B3055-00 - Theft Deterrent Module - No transponder modulation or no transponder
  • B3031-00 - Theft Deterrent Module - Security controller in learn mode
  • B1000-34 - Theft Deterrent Module - Electronic control unit - RAM malfunction
I cleared the codes and some would return if the car failed to start and others never returned. I started thinking I would have to replace the Theft Deterrent Module and get it & my keys/fobs reprogrammed. But I have to say that I was never stranded by the Impala. Sometimes I would have to try 5-10 times but every time it did eventually start although I was trusting it less and less. The intermittent starting also affected the remote start function.

I was about ready to replace the Theft Deterrent Module when I stumbled across this video about a no start 2013 Impala by ScannerDanner - that diagnosed the problem as a bad under the hood fuse box! Not the relay but the actual fuse box!

I recently purchase a 2014 Impala Limited LS with low miles to replace my 2012 Impala LT. It turns out the 2012 -2013 Impala and 2014 - 2016 Impala Limited use the same under the hood fuse box. So I swapped the under the hood fuse boxes between my 2 Impalas.

Now my 2012 Impala started every time via the key or remote start. And my 2014 started not starting and giving the same DIC message - Service Security System.

I was hoping to find a decent used fuse box at the local u-pull junk yards, but every Impala I found either had front end impact damage or the fuse box was already gone. I did find used fuse boxes on eBay for $50 and up, but I finally decided to buy a new one online for $140. The new fuse box came complete with all of the fuses and plug-in relays installed plus cover. I put the new fuse box in the 2014 Impala limited and kept the 2014 fuse box in my 2012. Now both Impalas start every time via the key or remote start.

I did tear apart my defective fuse box and as ScannerDanner said in his video, there are relays and other electronics on the circuit board inside the fuse box. So I either had bad connection or dying component on the fuse box circuit board.

Hope this post will help someone else solve their own intermittent starting issues with much quicker than I did.

 
#3 ·

I had the same problem. New fuse block and four years later still starts every time. Thanks for the pics.
 
#4 · (Edited)
Nine P3CN012W1 Compact Power Relays soldered to the PC board. Datasheet attached.
Relays eventually fail. Fact of life. These look like they cost around $1.50 each. Even if they're $5 each it's around $50 in parts and shipping to replace all nine.

Several SMT resistors that no doubt suffer from the same thermal fracturing solder joints that the small SMT resistors in the T800 Instrument clusters, radios, and climate control heads do. They need LEAD in the solder. Good old fashioned 60 : 40, Sn : Pb.

I see four sets of three terminals at the top centre of the printed circuit board. What lives on the other side?

How difficult was it to separate the case halves?

I find this interesting. I have an intermittent no-crank on my 2005 2500HD Silverado. When it doesn't crank I can run the starter by jumping from the BAT terminal to the CRANK terminal on the starter but jumpering the 30-87 terminals in the Metripak 280 starter relay socket of the power distribution block does nothing. Nothing else seems to be amiss. It starts right up and runs just fine cranking it direct and then works fine for months. Then it malfunctions for 2-3 cycles. It's the same electronic generation as these cars.

I have the gear and experience to repair things like this board.
 

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#5 ·
hatzie

The upper and lower plastic around the circuit board was attached (sonic welded? / glued?) on all sides. Since I didn't need it anymore, I used a flat bladed screwdriver to break the seal and separate the upper / lower plastic. I had to work the screw driver around all edges, there was gap that the screw driver fit in nicely. I did crack the plastic in places but if you were gentler, you could get it apart without much damage. Then I guess you could use some glue or sealant to reattach them after repair.

The other side was just the pins for the for the 4 large wire harnesses connectors that the fuse block plugs into, one for each bolt. I believe there was some printed circuit lines on this side also. But I don't remember any electrical components. When I get home from work, I will take clearer pictures of both sides of the circuit board and post them.

In my online searches, I found this problem to fairly common in many late 2000's and early 2010's GM vehicles. I do recall at least one Silverado in my search results.
 
#8 ·
hatzie
I tried to clearer pictures but it was a challenge getting the camera to focus on the circuit board and not components or pins. There are only 4 center bolt holes so you can see there is a lot of overlap on the top and bottom pictures. The bottom has no components but id does have a large power buss that battery cable connects to.


 
#11 ·
aftongrenat - There are more 2012-13 impalas and 2014-2016 impala limited showing up in all 4 pull your own part junk yards in the Denver area. With fewer older impalas on the road, I would guess you should be able to find an impala without front end damage and an under hood fuse box.

You can subscript to inventory notice emails for specific models from the pull your own part junk yards so you can immediate notice when an impala arrives in inventory.

Ebay is another choice and it might have some limited warranty. Most of the used fuse boxes on each are coming from an auto recycler, so you might get one locally if you can.
 
#13 ·
in my Mar 29,2021 post above, I wrote:

"The upper and lower plastic around the circuit board was attached (sonic welded? / glued?) on all sides. Since I didn't need it anymore, I used a flat bladed screwdriver to break the seal and separate the upper / lower plastic. I had to work the screw driver around all edges, there was gap that the screw driver fit in nicely. I did crack the plastic in places but if you were gentler, you could get it apart without much damage. Then I guess you could use some glue or sealant to reattach them after repair"

Which is a good thing because I didn't remember my method I used...hope this answers your question. The retaining bolts hold the wire harness to bottom of the fuse block. But they don't hold the 2 halves together.