Good Morning everyone, my name is James and I recently purchased my first corvette. When I finally had the chance to get it smogged I was told it needed to been seen by the state ref. So for some backstory, when I went to buy the car the owner said it had stopped running AFTER he received a new key for it. So I went to check it out and I got it running by adding a small little resistor to connect the purple/black wire and white/black wire together. A couple days go by before I go to get it smogged, the vette says charge system fault and reduced engine power. The c5 would start and run, but for no longer than a second. I ended up replacing the aftermarket alternator with another one that I assured would work, as well as the walmart battery with an optima red top. It fixed the issue for few days until charged system fault popped up again. Although now it starts up fine and runs and drives fine even though it still says CSF. I drive the car to get smogged and they come back saying it needs to be seen by a state ref. I went to the state ref this morning and failed with little to no idea why. I pulled my codes when i got back and got these:
P1280 h c
P1626 h
p1638 h

C2115
c2100 hc
C2105
C2110
A lot of the rest of the codes are u1064 which Im not sure if they have a huge part in me not passing state ref. I apologize for the long post any help or guidance to getting this thing to pass state ref and smog would be greatly appreciated.

 

P1280 h c APP Sensor 2 Circuit
P1626 h Theft Deterrent System Fuel Enable Circuit
p1638 h Has to due with charging system/Alt issue

C2115 Left Rear TPM Sensor Malfunction
c2100 hc Left Front TPM Sensor Malfunction
C2105 Right Front TPM Sensor Malfunction
C2110 Right Rear TPM Sensor Malfunction

I found this thread and it might have some info that may help you or atleast someone who has had similar issues you may be able to talk with. Seems as though the alt's are not the same for all C5's based on the thread below.

P1637 and P1638 PCM codes - CorvetteForum - Chevrolet Corvette Forum Discussion

 

Aside from whatever issues you have, you need a scanner capable of reporting I/M readiness ......otherwise you have no idea what is failing.

 

Exactly what Lucky said.
I bought the correct Valeo alternator for my 2000 from Rock Auto. Perhaps they still have them. That was just a couple years ago.

 

James you can view the results of your test here.
The referee should have gone over the results with you.

If you're new to California I suggest you talk to some members in the regional forums or some local Corvette club members. People who have dealt with the specifics of the California system are likely a good source of information.

 

I will for sure order a scanner today, as of right now I got a shop running codes and pulling the diagnostics. Ill let you know what they can find.

 

Sadly the referee only handed me a paper telling me to fix whatever it is and bring it back. When I asked him what it could be he only mentioned the sensors/monitors. Now when I clicked on the link it showed the previous owner’s attempted smog check that failed because of “data check fail” I’m not entirely sure what this means. Ill see if I can get in contact with a local forum member as well.

 

What year is it? It probably sensed a illegal tune was installed

 

Its a 2002 with about 111k miles

 

I think at 2002, they could tell you have modified your ecu by its checksum. You will have to reflash your ecu back to its stock tune assuming it will run with a stock tune

 

There's a whole thread in the SoCal section on this, it was pretty far back and would require a little digging to find. My recollection from that thread is that C5 didn't fall under the checksum verification, it started at C6. But a fail result could still occur if there were any tweaks to readiness monitors.

 

Oh? Is that an editable portion of the PCM?

 

Great question which I am unable to answer.
I am familiar with this possibility on other cars / tuning platforms but not this one.

 

Which ones?

 

If the car has active codes, it will fail the smog check for that alone. Had your cleared the codes prior to going to the ref?
Typically one has to clear codes (with the scanner) and than drive the car for about 50 miles, without codes regenerating to pass the readiness check.

The C5 is one of the few cars you don't need a scanner for basic code checks and clearing
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To access diagnostic codes on a C5 Corvette (1997-2004), turn the ignition to the "On" position without starting the engine. Press the "Reset" button on the Driver Information Center (DIC) to clear any messages. Then, press and hold the "Options" button while pressing the "Fuel" button four times within 10 seconds to enter the diagnostic mode. The system will automatically cycle through different modules. Pressing the "Fuel" button again will switch to manual mode, allowing you to scroll through individual modules. [ , 2, , 4]
This video demonstrates how to enter diagnostic mode on a C5 Corvette: Detailed Steps:

1. Turn the ignition to the "On" position: Ensure the engine is off. [2, 4]
2. Clear any messages: Press the "Reset" button on the DIC to clear any existing messages on the display. [2, 4]
3. Enter diagnostic mode: Press and hold the "Options" button and then press the "Fuel" button four times in quick succession (within 10 seconds). [2, 4]
4. Automatic mode: The system will automatically scroll through the modules (PCM, TCS, BCM, etc.) displaying any Diagnostic Trouble Codes (DTCs) associated with each. [2, 4]
5. Manual mode: To access specific modules and view their codes individually, press any button (except "E/M" or "Reset") to enter manual mode. [2,
   5
   ]
6. Navigate through modules: Use the "Options" button to scroll between modules and the "Fuel" button to view codes within each module. [
   5
   ,
   6
   ]
7. Read the codes: The codes will be displayed on the DIC. You can then look up the codes online or in a repair manual to understand the specific issues. [
   1
   , 2,
   7
   ]
8. Exit diagnostic mode: Pressing the "Reset" button will exit the diagnostic mode. [2,
   5
   ]

Explanation of Codes:

• Current Codes: These codes are designated with a letter suffix "C" and indicate a malfunction that is currently present. [2]
• Historical Codes: These codes are designated with a letter suffix "H" and indicate past malfunctions that may or may not be present currently. [2, 8]

 

Prior to my Corvette I did a bunch with the Audi B5 chassis, especially 2001 A4 and S4. It's common with those cars to tune readiness monitors and set them to pass/ready instantly, but CA smog test equipment can catch this and will flag the car as "tampered". One tuner I liked figured out adding a delay on the setting of readiness which deceived smog test equipment.

 

Interesting. That certainly defeats the whole purpose of the system.

 

Hey guys, been close to a month and now I’m only suffering from p1280 and p1281 DTCs. I purchased a new APP sensor thinking it would be the fix but sadly the codes are still there. Im assuming next step is to look at my TAC module and check my connections?