Freeze Frame Data

IMPORTANT: A "fault" mentioned below is an error flag set in the PCM indicating a diagnostic test has run and failed. The "fault" is designated by a DTC in Freeze Frame/Failure Record information, but does not suggest that the DTC is active.

The Scan tool displays vehicle malfunction history information located in the Diagnostic Trouble Code menu under the subheading Freeze Frame/Failure Records. Freeze Frame/Failure Records contain a maximum of 7 records; 1 FREEZE FRAME plus 6 FAILURE RECORDS.

Government regulations mandate that all emission related faults store freeze frame data, designated as Failure Record "0" on Scan tool, at time of the first failed test. The first emission related fault that sets after a code clear or battery disconnect is stored in freeze frame and can only be overwritten by Fuel Trim and Misfire faults. All other emission related faults that set, will not be stored in freeze frame unless the initial fault is cleared.

Failure records 1 through 6 on Scan tool store information at time of first fault and are undated every time the PCM runs a test and fails the diagnostic. If another fault were to occur, the DTC in record 1 would be moved to record 2 and the new DTC would be placed in record 1 (first in, first out). If a new failure is detected while all failure records are full, the number 6 record will be erased (oldest) and the newest fault will be updated to failure record 1.

The following is an overview of DTC types and how information is stored in memory.

EMISSION RELATED
TYPE A - First fault during first ignition cycle - Freeze Frame "0" stores DTC plus information, Failure Record 1 stores (same record as freeze frame "0") and updates with every failed test, DTC becomes active, MIL illuminates.

TYPE B - First fault during first ignition cycle - Freeze Frame "0" stores DTC plus information, Failure Record 1 stores (same record as freeze frame "0") and updates with every failed test.

Second ignition cycle with same fault - Failure Record 1 updates, DTC becomes active, MIL illuminates.

NON - EMISSION RELATED
TYPE C - First fault during first ignition cycle - Failure Record 1 stores DTC plus information and updates with every failed test, DTC becomes active, Service telltale illuminates.

TYPE D - First fault during first ignition cycle - Failure Record 1 stores DTC plus information and updates with every failed test, DTC becomes active.

It is important to remember that the DTC as well as any stored failure record information will be erased if the vehicle battery has been disconnected or a clear DTC command is issued to the PCM. DTCs and failure record information will also be erased if 40 passes (only one pass per ignition cycle is counted) have been recorded without any faults. All emission (DTC type A or B) and non-emission (DTC type C and D) codes require this 40 pass criteria.

TRIP
A "TRIP" is defined as a key On, Run, key Off cycle in which all the criteria were met for a given diagnostic test to run. During any given drive cycle, key On, Run, key Off criteria may or may not have been met to perform all diagnostic tests. No "TRIP" will occur for a given diagnostic until the vehicle is driven in such a manner as to meet all the enable criteria. If a test is desired on a particular subsystem to determine if it "passes" or "fails," refer to the specific DTC for test parameters. The parameters are calibrated conditions the PCM requires in order to perform the test. If a test has not been run, monitor the Scan tool PASS/FAIL DTC status at the time the parameters have been met.

Warm Up Cycle
A warm-up cycle is defined as engine temperature reaching a minimum of 71°C (160°F) and a rise in temperature of at least 22°C (72°F) over the course of a trip.

FREEZE FRAME/FAILURE RECORDS
FREEZE FRAME 0 will store the following:
^ DTC#
^ Distance Since Code Cleared
^ Distance Since First Failure
^ Distance Since Last Failure
^ Loop Status
^ Engine Load
^ ECT
^ Short Term FT
^ Long Term FT
^ TP angle
^ [1][2]MAP
^ Engine Speed
^ Vehicle Speed
^ IAT
^ Ignition I
^ O2S-1
^ HO2S-2
^ Fuel Level
^ Fuel Level to Cluster
^ CMP Resync Counter
^ Start Up ECT
^ IAC Position
^ Base PWM Cyl. #1
^ Base PWM Cyl. #2
^ Baro
^ Air Fuel Ratio
^ Engine Run Time
^ Air Flow
^ Fail Counter
^ Pass Counter
^ Not Run Counter
^ A/C Request
^ Brake Switch
^ Low Coolant Level
^ FC Relay Command
^ A/C Relay Command

Failure Records 1-6 will store the above information as well as:
^ EVAP Purge Solenoid
^ Current Gear
^ TCC Engaged

Each DTC will store all of the above parameters in the Failure Record as well as additional information based on the specific DTC. There are 7 different combinations of additional information ranging from 3 to 33 parameters for all of the powertrain DTCs.

The failure records for the PCM will record all of the above information plus the additional information specific to the particular DTC. The failure record will be erased from PCM memory during a code clear, battery disconnect or after 40 passes (only one pass per ignition cycle is counted) with out any faults detected in that circuit.