I've printed out the DIC Error Code listing previously, and for about the 3rd time, I've deleted the codes that have popped up when the Check Engine warning light came on. As far as I've been told by a Forum member or two when previously posting a question on the codes, as long as "H" is part of the error code, then it's a "historical condition" that has cleared. The codes that have popped up have always had an "H".

But what causes these codes? An electronic hiccup? A bump that affects a relay or one of the electronic modules?

Here are the codes that popped up this time:
10-PCM P0420 H C TWC System Low Efficiency Bank 1
10-PCM P0430 H C TWC System Low Efficiency Bank 2
AO-LDCM U1064 H Loss of Communications with BCM
A1-RDCM U1064 H Loss of Communications with BCM
A6-SCM U1064 H Loss of Communications with BCM
A6-SCM B2860 H I didn't see this code on the list

Unless someone can tell me something different, I'm not worried, just curious!

 

I thought that if it had a C at the end of the code, it meant that it was current. P0420 HC would indicate that it is historical (occurred before) and current (resurfaced again).

Someone correct me if I'm wrong.

 

OneBadGix is correct... two of those are current.

how old is your battery?

 

It's the same battery that came with the Vette when I got it new on August 14, 2002, but that was also 66, 250 miles ago!

So, what does TWC System Low Efficiency Bank 1 and 2 mean? What system is degraded or having a problem? How serious is this code? What could this lead to?

Having a list of what the codes are is nice in one way but not much use if you don't know what is actually meant by the code. I don't want to naively be deleting codes, and up until Gix's and bsmith's responses, I didn't realize that I could possibly be ignoring something or doing something wrong.

Any advice/recommendations are appreciated!

 

The 2 P codes indicate a current problem with both cats, O2 sensors or the wiring. You will never pass a state inspection (if you have one) if this condition persists. If your car is stock in that area it still may be under the special emissions warranty.

The B2860 codes indicates a previous problem with steering wheel position sensor. The U1064 code is very common and usually isn't meaningful as long as it stays with just an H. I would clear all the codes but the "P" codes will, probably, come back.
Any work done to or changes made to the exhayst system or O2 sensors?

P0420
CIRCUIT DESCRIPTION
In order to maintain a reasonably low emissions of Hydrocarbons (HC) , Carbon Monoxide (CO) , and Oxides Of Nitrogen (NOx) , the engine controls system uses a 3-way catalytic converter. The catalyst within the converter promotes a chemical reaction which oxidizes the HC and CO present in the exhaust gas. This reaction converts them into harmless water vapor and Carbon Dioxide. The catalyst also reduces NOx, converting it to Nitrogen. The PCM monitors this process using Bank 2 HO2S #2. Bank 2 HO2S #2, located in the exhaust stream past the 3-way catalytic converter, produces an output signal which indicates the oxygen storage capacity of the catalyst. This determines the catalysts ability to convert exhaust emissions effectively. If the catalyst is functioning correctly, the Bank 2 HO2S #2 signal will be far less active than that produced by Bank 2 HO2S #1. This indicates that the 3-way catalytic converters oxygen storage capacity is below a threshold considered acceptable.

When the conditions for running this DTC are met, the following occurs:


The PCM captures the current rear HO2S rich/lean status.
The Air Fuel ratio transitions from rich to lean or lean to rich depending on the capture rear HO2S rich/lean status.
The Air Fuel ratio transitions a second time opposite the first Air Fuel ratio transition.
The PCM captures the response time (the time the HO2S goes from below 300 mV to above 600 mV and from 600 mV to below 300 mV ) of the front and rear Heated Oxygen sensors when the Air Fuel ratio transitions occurred.
The PCM measures the time it takes the rear HO2S voltage to cross a reference rich/lean threshold minus the time it takes the front HO2S voltage to cross the same rich/lean threshold. The time difference from the front and rear HO2S is the oxygen storage capacity of the catalyst. This DTC sets if the time exceeds a predetermined threshold.
CONDITIONS FOR RUNNING THE DTC


AIR, CKP, CMP, IAT, IC, MAF, MAP, ECT, TP, EVAP, Right Bank HO2S, Misfire, Right Bank Fuel Trim, Injector, VSS, Engine Protection, or Transmission DTCs are not set.
The engine is operating.
The ECT is greater than 75°C (167°F) .
The vehicle speed is less than 136 km/h (85 mph) .
The throttle angle is greater than 10 percent.
The engine speed is less than 4000 RPM .
The MAP is between 25 kPa (3.6 psi) and 80 kPa (11.6 psi) .
The air flow is between 14 gm/s and 40 gm/s .
The closed loop fuel control is enabled.
CONDITIONS FOR SETTING THE DTC
The PCM determines if the oxygen storage capability of the catalytic converter has degraded below a calibrated threshold.

ACTION TAKEN WHEN THE DTC SETS


The PCM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC


The PCM turns the malfunction indicator lamp (MIL) OFF after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A last test failed (current DTC) clears when the diagnostic runs and does not fail.
A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
Use a scan tool in order to clear the MIL/DTC.
TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.


Before replacing the Three Way Catalytic Converter, correct any conditions which may have damaged the catalyst.

 

Wow, that's got to be the more thorough answer I've ever gotten! Thanks! I'm going to print that out for reference in the future.

Funny you should ask about "any changes made to the exhaust system or O2 sensors?"

I replaced the stock exhaust back in March of this year with long tube headers, high flow cats, and an x-pipe. I had already put on a catback about a year before that. The place doing the work reinstalled the O2 sensors, and this is the first time I've gotten that error message. I reset the codes 2 days ago, and they haven't come back yet.

Inspection??? I don't need no stinkin' inspection since I live in Statesboro, GA, that is.

So, with this info, am I really facing any problems? Can I just delete these codes without any concerns if they pop up again?

Thanks again!!!

 

Just clear them and see if any come back. My guess is the P codes will be persistent.

 

Thanks again for the response. Today is the 3rd day since I've reset the codes, and they havent come back yet.

I'll let yall know if it persists!