I have a question, as I understand it you cannot pull the error codes on a C6. My question is, if I get no error notifications from the DIC can I assume I have no errors stored in the DIC?

 

No, I don't think that's true, but maybe others will explain that.

 

 

Our hero Talon90 s/b here any minute now...

He knows all!

 

No, and here is probably more then you ever wanted to know about that!!



Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Emissions Related DTCs
Action Taken When the DTC Sets - Type A
• The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

• The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Action Taken When the DTC Sets - Type B
• The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.

• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

• The following applies to misfire DTCs:

- If the control module detects a low level or an emission level misfire condition during 2 consecutive trips, the control module illuminates the MIL.

- If the control module detects a high level or catalyst damaging misfire, the control module flashes the MIL at a rate of once per second.

- If the control module detects a misfire during 2 non-consecutive trips, the stored conditions are compared with the current conditions. The control module illuminates the MIL when the following conditions occur:

• The engine load is within 20 percent of the previous test that failed.

• The engine speed is within 375 RPM of the previous test that failed.

• The engine coolant temperature is in the same range of the previous test that failed.

• The following applies to fuel trim DTCs:

- If the control module detects a fuel trim condition during 2 consecutive trips, the control module illuminates the MIL.

- If the control module detects a fuel trim condition during 2 non-consecutive trips, the stored conditions are compared with the current conditions. The control module illuminates the MIL when the following conditions occur:

• The engine load is within 20 percent of the previous test that failed.

• The engine speed is within 375 RPM of the previous test that failed.

• The engine coolant temperature is in the same range of the previous test that failed.

Conditions for Clearing the MIL/DTC - Type A or Type B
• The control module turns OFF the MIL after 4 consecutive ignition cycles that the diagnostic runs and does not fail.

• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

• Clear the MIL and the DTC with a scan tool.

Non-Emissions Related DTCs
Action Taken When the DTC Sets - Type C
• The control module stores the DTC information into memory when the diagnostic runs and fails.

• The MIL will not illuminate.

• The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.

• The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC - Type C
• A current DTC Last Test Failed clears when the diagnostic runs and passes.

• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.

• Clear the DTC with a scan tool.

Action Taken When the DTC Sets - Type D
• The control module will take default actions but no DTC will be stored in Failure Records.

• The MIL or SVS will not illuminate.

Conditions for Clearing the DTC - Type D
Clear the DTC with a scan tool.
© 2008 General Motors Corporation. All rights reserved.

 

Excellent post (as always).

As stated the car can and will deal with a number of problems on its own and may do so without ever allerting the driver with a message or a CEL. That does not mean that they never happen. Most would be classified as communication issues where a particular system or sensor did not communicate the appropriate message at the appropriate time. It could also mean that a particular parameter did not meet a value on a calibration table. These also don't necessarily mean that anything needs to be done on the owners part. The car just keeps track of these issues and if a problem arises that is so far outside of anticipated values or if the car simply can't deal with the condition it will alert you with one of the various messages that it can provide.

We also need to remember that the vocabulary of the car and its systems is limited in so much as the message presented may not always lead to a clear understanding of the particular problem. This is why proper diagnosis of the problem is important.

 

Glad I had a large size popcorn

 

 

or if the car simply can't deal with the condition it will alert you with one of the various messages that it can provide.

Oh, kinda like "Help I've fallen and I can't get up"

 

Thanks Talon90 .

We just plug in the scanner, read the code, change a part and it's all better, ! I wish it was sooooo!

 

Yes. As an example, I have never had a MIL lamp. But two weeks ago I was using a Tech 2 to active the afterblow feature for my HVAC blower. While I had the Tech 2 connected I looked for codes for each of the onboard modules. It was amazing, some of the codes that were stored, which NEVER turned on the MIL. I had codes for seat position error, and other stuff I never knew I had, and then some.