amelillo

so i just got my 06 ss sc back from the dealer i had to get a few problems fix and i was just looking over every thing they did and it said my car was throwing two codes but i was woundering y i had no check engin light on befor i brought it to the dealer it kinda made me wounder y didnt my light come on if it was throwing two codes off the codes were p0171 and p0300 does any one know what these two codes mean and y i didnt get a check engin light ???? thanks for any answers

Coblasts

Ones a lean code(p0171) and the other is for misfires(p0300),And the would of put up a ses light as far as I know.


Heres some reading to educate yourself.

Diagnostic Trouble Codes (DTCs)
The powertrain control module (PCM) is programmed with test routines that test the operation of the various systems the PCM controls. Some tests monitor internal PCM functions. Many tests are run continuously. Other tests run only under specific conditions, referred to as Conditions for Running the DTC. When the vehicle is operating within the conditions for running a particular test, the PCM monitors certain parameters and determines if the values are within an expected range. The parameters and values considered outside the range of normal operation are listed as Conditions for Setting the DTC. When the Conditions for Setting the DTC occur, the PCM executes the Action Taken When the DTC Sets. Some DTCs alert the driver via the malfunction indicator lamp (MIL) or a message. Other DTCs do not trigger a driver warning, but are stored in memory. The PCM also saves data and input parameters when most DTCs are set. This data is stored in the Freeze Frame and/or Failure Records.

The DTCs are categorized by type. The DTC type is determined by the MIL operation and the manner in which the fault data is stored when a particular DTC fails. In some cases there may be exceptions to this structure. Therefore, when diagnosing the system it is important to read the Action Taken When the DTC Sets and the Conditions for Clearing the DTC in the supporting text .

There are different types of DTCs and different actions taken when the DTCs set. Refer to Diagnostic Trouble Code (DTC) Type Definitions for a description of the general characteristics of each DTC type.

DTC Status
When the scan tool displays a DTC, the status of the DTC is also displayed. The following DTC statuses are indicated only when they apply to the DTC that is set.

Fail This Ign. (Fail This Ignition): Indicates that this DTC failed during the present ignition cycle.

Last Test Fail: Indicates that this DTC failed the last time the test ran.

MIL Request: Indicates that this DTC is currently requesting the malfunction indicator lamp (MIL). This selection will report type B DTCs only when they have requested the MIL (failed twice).

Test Fail SCC (Test Failed Since Code Clear): Indicates that this DTC that has reported a failure since the last time DTCs were cleared.

History: Indicates that the DTC is stored in the powertrain control module (PCM) History memory. Type B DTCs will not appear in History until they have requested the MIL (failed twice). History will be displayed for all type A DTCs and type B DTCs (which have requested the MIL) that have failed within the last 40 warm-up cycles. Type C DTCs that have failed within the last 40 warm-up cycles will also appear in History.

Not Run SCC (Not Run Since Code Clear): DTCs will be listed in this category if the diagnostic has not run since DTCs were last cleared. This status is not included with the DTC display since the DTC can not be set if the diagnostic has not run. This information is displayed when DTC Info is requested using the scan tool.