Scan Tool Testing and Procedures

DATA STREAM INFORMATION
There are several access modes through which data may be extracted from the ECM via the J1962 connector using the relevant scanner.

Freeze Frame Data Access List:

Parameter Identification (PID) - Access (Mode 1)
Generic OBD II PID List
X = Freeze Frame PID (refer to Freeze Frame Access for more information)
Open = Open loop, have not satisfied conditions for closed loop.
Closed = Closed loop using O2S(s) as feedback for fuel control.
OP DRV = Open loop due to due to driving conditions (heavy acceleration).
OP SYS = Open loop due to vehicle system fault.
CL O2S = Closed loop fuel control, but fault with 02S sensor(s).

Freeze Frame Data Access List:

Freeze Frame Data - Access (Mode 2)
Freeze Frame Data allows access to emission related data values from specific generic PIDs. These values are stored the instant an emission related DTC is stored in Continuous Memory. This provides a snapshot of the conditions that were present when the DTC was stored.

Once one set of freeze frame data is stored, this data will remain in memory even if another emission related DTC is stored, with the exception of Misfire or Fuel System DTCs.

Once Freeze frame data for Misfire or Fuel System DTC is stored, it will overwrite any previous data and freeze frame will not be further overwritten.

When a DTC associated with the freeze frame is erased or a Powertrain Control Module (PCM) memory reset is performed, new freeze frame data can be stored again.

In the event of multiple emission related DTCs in memory, always note the DTC for the freeze frame data.

Test Results:

Oxygen Sensor Monitoring Test Results - Access (Mode 05)
The Oxygen Sensor Monitoring Test Results allows access to the On-Board sensor fault limits and actual values during the test cycle. The test cycle has specific operation conditions that must be met (engine temperature, load, etc.) for completion. This information helps to determine the efficiency of the exhaust catalyst. Listed are the tests and test identification numbers that are available.