874 Engine Control Systems II Technician Handbook TIS Techstream Diagnostic Trouble Codes Screen The TIS Techstream displays all ECU specific DTC information on one screen, including
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In 1988, the California Air Resources Board (CARB) set the requirement that all vehicles have a system that could identify faults
in the emission and powertrain system This is recognized as OBD I
At the same time OBD requirements were set, CARB also set the requirements for OBD II The federal government adopted these requirements and they went into effect beginning in 1996 OBD II standards greatly enhanced the on-board diagnostic system’s capabilities and changed the way technicians troubleshoot engine and emission control systems
CAN, which stands for Controller Area Network, is a standard (or
“protocol”) for high-speed electronic communication CAN OBD II requirements do not significantly change the way technicians troubleshoot engine and emission control systems Instead, CAN improves the speed and accuracy of information exchange among the vehicle’s ECUs, and between the vehicle and the diagnostic tester CAN OBD II must be phased in by 2008
OBD Generations
OBD
OBD II
CAN OBD II
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TIS Techstream
Diagnostic Trouble
Codes Screen
The TIS Techstream displays all ECU specific DTC information on one
screen, including Code name and Description, and specifies it as a Current, Pending, History and/or Permanent DTC
The numbers below correspond to the number callouts in the illustration
1. These columns display the DTC as Current, Pending, History and/or Permanent DTC
2. Use the eraser button to clear DTC(s), monitor information, etc
3. To access Freeze Frame data, click on the snowflake icon next to the DTC, or highlight the DTC and click the snowflake button at the bottom of the screen
4. Use the disc button to store DTC(s), Freeze Frame, and Monitor
information to the Stored Data tab If DTCs are not stored from the
DTC or Monitor screens, the current DTC and Monitor Status/
Results will not be stored to the Stored Data tab and cannot be
accessed later
5. The current user is displayed here Double-click the current user to
access the Change/Create User pop-up window
Diagnostic Trouble Codes are set when the ECM detects a malfunction in
a monitored component or system There are two types of DTCs:
• One Trip DTCs
• Two Trip DTCs
Diagnostic Trouble
Codes (DTCs)
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A trip is defined as an engine-operation drive cycle that contains all
of the necessary conditions for a particular test to be performed
Some DTC(s) may require a warm-up cycle, while others require just an ignition-ON cycle
An OBD II Trip consists of an engine start following an engine OFF period, with enough vehicle travel time to allow the OBD II
monitoring sequences to complete their tests The vehicle must be driven under a variety of operation conditions for ALL tests to be performed
OBD II standards define a warm-up cycle as a period of vehicle operation, after the engine was turned ON, in which coolant temperature rises by at least 40 degrees F (22 degrees C) and reaches at least
160 degrees F (88 degrees C) The ECM determines a cold start by comparing the engine coolant temperature (ECT) and the intake air temperature (IAT)
Trip
OBD II Trip
Warm-Up Cycle
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There are some DTCs that will set in one trip A one trip DTC will store a code that can be observed in the DTC screen, set a Freeze Frame, and light the MIL Also, depending on model year the DTC will be stored as permanent
MIL ON One Trip
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When a two trip emissions-related fault is detected for the first time,
a DTC related to that fault is stored as a pending code If the fault occurs again on the second drive cycle, then the DTC is stored as a current, permanent and light the MIL Also, the DTC and Freeze Frame are recorded in memory The pending code will be erased if the monitor test does not detect a fault under the same conditions
on the next trip
MIL ON Two Trip
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The MIL will blink during the first trip when a misfire occurs that will raise the temperature of the catalytic converter enough to cause damage The blinking may be intermittent because of changes in engine load and the severity of engine misfire If the condition reoccurs during the second trip, the MIL again blinks and the DTC and Freeze Frame are recorded in memory The MIL will be on solid once the DTC is recorded if the misfire is no longer severe enough
to damage the catalytic converter See Misfire Diagnosis section for more information
MIL Blinking
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MIL OFF The MIL is turned OFF after 3 consecutive trips without the fault being detected
After the MIL is turned off and 40 successful trips with no fault have been detected, the DTC and Freeze Frame data will be erased from memory; however, the DTC will remain in history until cleared
MIL Blinking:
• Misfire detected severe enough to damage the catalytic converter MIL ON:
• One trip fault
• Two trip fault MIL OFF:
• Three consecutive trips, fault not detected, monitor operated DTC Memory Erasure:
• 40 trips, fault not detected
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To tighten emission testing standards and decrease the loopholes associated with monitor readiness status (Some state emission testing allow up to two monitors to be “Incomplete” at the time of inspection without failing the test) Permanent DTCs were designed
to set anytime the MIL is commanded on and cannot be erased from memory until the fault is corrected and normal judgment is
determined Permanent DTCs will be standard on all Toyota models
by 2010 model year Clearing DTCs can no longer be accomplished solely by the eraser button on Techstream
There are two methods to successfully clear Permanent DTCs:
• The vehicle is driven for 3 consecutive trips and normal judgment is confirmed by associated monitors
• After clearing DTCs with Techstream or disconnecting the negative battery terminal, the ECM must see normal judgment for the respective DTC by completing two drive patterns:
Confirmation Driving Pattern and an Universal Trip Driving Pattern
Permanent DTC
Clearing Permanent DTCs
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Confirmation Driving Pattern
The Confirmation Driving Pattern is used to provide DTC specific vehicle operation to confirm normal judgment This driving pattern is specific for each DTC and system monitoring strategy After normal judgment is obtained the Universal Trip Driving Pattern will need to be completed to fully clear the permanent DTC column (or three
consecutive drive cycles with normal judgment)
The Universal Trip Driving Pattern (UTDP) can be performed consecutively with the Confirmation Drive Pattern Be sure to let the engine idle for 30 or more seconds before proceeding and drive the vehicle at 25 mph or more for at least 5 minutes
It is possible to complete the drive pattern even if the vehicle decelerates below 25 mph during drive cycle provided that the vehicle
is driven at or above 25 mph for a total of 5 minutes Allow 10 minutes
or more to elapse from the time the engine is started and cycle the ignition to confirm the permanent DTCs have been cleared
Universal Trip Driving Pattern
NOTE
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OBD II Diagnostic Trouble
Codes (DTC)
OBD II DTCs must follow a standardized format set by the Society
of Automotive Engineers (SAE) The following is a summary of the DTC standardized format:
• Stored when fault confirmed (one or two trip)
• Remains active for 40 cycles (without fault)
• Freeze Frame stored
• Remains in history until cleared The first digit indicates component area group
• Example: P = Powertrain, B = Body, etc
The second digit indicates SAE controlled or manufacturer specific
• Example: 0 = SAE controlled, 1 = manufacturer specific, 2 = SAE controlled, 3 = manufacturer specific and SAE reserved The third digit indicates DTC subgroup
• Example: 0 = total system, 1 = fuel and air metering, etc
The fourth and fifth digits indicate area or component involved
• Example: 71 = Fuel Trim
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Freeze Frame Freeze Frame data, sometimes referred to as FFD, provides
information of the conditions that were present at the time the DTC was recorded in memory By re-creating the vehicle speed, engine RPM, and engine load, as well as other conditions noted, the technician can duplicate the concern
Two Freeze Frames can be stored in the ECM The first is reserved for information related to misfire and fuel control, which have priority over other DTC(s) The second, if not occupied by one of the priority DTC(s), will store information for the first non-priority DTC that occurs The Freeze Frame information updates if the condition reoccurs
When using the Techstream, a snowflake symbol next to the Trouble Code ID indicates there is Freeze Frame data associated with that DTC If Freeze Frame data is available, double-click the snowflake next
to the DTC or highlight the DTC and click the snowflake at the right of the screen to display the data
bottom-Earlier model vehicles (most 2003 and earlier) record one (1) Freeze Frame per applicable DTC at the time the DTC set
Later model vehicles (some 2003 and later) display five (5) Freeze Frames per applicable DTC with
0.5 seconds between each frame:
• -3: three frames prior to the DTC being set
• -2: two frames prior to the DTC being set
• -1: one frame prior to the DTC being set
• 0: one frame at the time the DTC set
• +1: one frame after the DTC set
With the Techstream, the Freeze Frame parameter list can be reduced
by making a Custom List
NOTE
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Data List
NOTE
The Data List provides important current parameter values
The numbers below correspond to the number callouts in the illustration
1. To create a custom data list, select all desired parameters,
and then click the New List button
2. To remove parameters from a data list, select the parameters,
and then click the Remove button
3. The Data List Manager can also be used to create a custom
data list
4. Use the data list pull-down menu to access optional data lists
If a custom list has been created, it can be accessed from the pull-down menu at any time during the session
5. Use the Graph button to graph parameters
6. Anytime the Record button is enabled (red), a snapshot can
be recorded
7. The ms reading displays the current refresh rate A smaller number indicates a faster refresh rate (more real-time data)
Most CAN OBD II vehicles will display a reading around 200
ms OBD II vehicles (non-CAN) will display a much larger
(slower) refresh rate To reduce the refresh rate in Data List
mode, reduce the number of parameters of the data list by making a custom data list
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Graphing data list parameters can aid in diagnosis
The numbers below correspond to the number callouts in the illustration
1. To graph, drag-and-drop the desired parameters from the data list to the right side of the window or double-click the desired parameters
2. The value in the center of the graph is the actual current graphed parameter reading This reading corresponds to the current reading
of the parameter in the data list to the left of the graph To add
parameter range grid lines, go to the individual graph Menu and select Graph Type 2
3. Graphing function is auto-ranging
The auto-ranging feature may not always work Go to Menu Enter Graph Setup to change graph time and range scales
4. Use the Menu button to change graph menu options such as graph
range, measuring time, etc
5. Use the Full Screen button to view the particular graph in full
screen mode
6. Use the Graph Type button to change the graph to a Line Graph, Bar Graph, Meter, or LED readout
7. Use the X button to remove a particular graph from the screen
8. Graph controls will be displayed at the bottom-left of the screen
Data List Graphing
NOTE
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Recording a snapshot will record all selected parameters during a configured amount of time This can aid in diagnosis After a snapshot is
recorded, it can be stored to the Stored Data tab, and the entire Service
Event File can be attached to a TAS case and forwarded to the Technical Assistance System (TAS) for review
The numbers below correspond to the number callouts in the illustration
1. To configure a snapshot, select Function Snapshot Configure
from the main toolbar
2. Configure the snapshot with the pull-down menus
3. Use the X button to exit out of the Snapshot Configure mode
4. Anytime the Record button is enabled (red), a snapshot can
be recorded
Pressing the <Space Bar> or using the on-screen Record button will
trigger recording a snapshot
Snapshot
NOTE
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Active tests allow the Techstream user to control specific components in order to test them for proper operation and electrical control Active tests can aid in diagnosis
Active Test
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A monitor is an ECM self-test of system components and circuits
The ECM uses monitors to check systems and components for malfunctions that will cause emissions to increase 1.5 times more than FTP (Federal Test Procedures) regulations permit These regulations are based on the emissions certification of the particular vehicle as tested and determined by the EPA (ULEV, SULEV, etc)
Readiness Monitor
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The goal of the OBD II regulation is to provide the vehicle with an on-board diagnostic system capable of continuously monitoring the efficiency of the emission control systems, and to improve diagnosis and repair efficiency when system failures occur
Monitor Information is stored in two monitor categories: Cumulative and Current The on-board tests performed by the ECM are separated into two types: continuous and non-continuous These are known as readiness monitors, or simply monitors
If a readiness monitor fails, DTC(s) specific to the failure(s) are set
Readiness Monitors
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The Cumulative Monitor displays readiness monitors that have run and completed at least one trip since the Monitor was last reset (DTCs Cleared) The Cumulative Monitor displays Test Results and Test Details for the previous Monitor trip When monitors are reset (DTCs Cleared), Cumulative Monitor status and result fields change
to Incomplete and Pass
Cumulative Monitor information can be used during emission testing
to verify that each Monitor has run, completed and passed at least one trip since the Monitor was last reset (DTCs Cleared)
Cumulative Monitor