Exploring Mode $06: Unlocking Advanced Diagnostic Data
Understanding Mode $06 in Automotive Diagnostics
Mode $06 is a crucial yet often misunderstood component. It represents a mode within the On-Board Diagnostics II (OBD-II) system that allows technicians to access advanced diagnostic data. This data provides a deeper insight into the vehicle’s health, enabling precise identification and resolution of issues that might not trigger the Check Engine Light (CEL). This article explores the intricacies of Mode $06, its importance, and how it is used in automotive diagnostics.
The Role of Mode $06
Mode $06 specifically deals with the results of non-continuous tests performed by the vehicle’s onboard computer. These tests are typically related to emissions control systems and other critical components that do not need constant monitoring but are checked periodically.
When the vehicle’s computer (the Engine Control Unit or ECU) performs these tests, it compares the results to predefined thresholds. If a test result falls outside the acceptable range, it indicates a potential problem. However, not all test failures immediately trigger the CEL. Mode $06 data allows technicians to see these test results before they become severe enough to set a DTC and illuminate the CEL.
How Mode $06 Works
Mode $06 data is stored as hexadecimal codes, which need to be interpreted to understand their meaning. Each test monitored by Mode $06 has a specific Test ID (TID), and each TID has several Component IDs (CIDs). The ECU records the minimum, maximum, and current values for each test.
For instance, if the vehicle tests the efficiency of the catalytic converter, Mode $06 will store the TID associated with the catalytic converter test, along with the results of that test. Technicians can then use a scan tool to retrieve this data, converting the hexadecimal values into human-readable information.
Accessing and Using Mode $06 Data
Accessing Mode $06 data requires an OBD-II scan tool capable of reading and interpreting this mode. Not all scan tools have this capability, so it’s essential to ensure the tool used is equipped to handle Mode $06 data.
Once the data is accessed, technicians can analyze the results to identify potential issues. For example, if the catalytic converter efficiency test result is marginal, it might suggest the converter is starting to fail but hasn’t yet reached the point of triggering a DTC. This early warning allows for proactive maintenance, potentially saving time and money on more extensive repairs.
Importance of Mode $06 in Diagnostics
The importance of Mode $06 in automotive diagnostics cannot be overstated. It provides a deeper layer of insight into the vehicle’s health, allowing technicians to:
• Detect issues early— By identifying problems before they trigger the CEL, technicians can address minor issues before they become major repairs.
• Improve accuracy— Mode $06 data helps in pinpointing the exact component or system that is underperforming, reducing guesswork and improving diagnostic accuracy.
• Enhance emissions compliance: Since many Mode $06 tests are related to emissions control systems, accessing this data helps ensure vehicles remain compliant with emissions standards.
What Mode $06 Monitors
Mode $06 is valuable for more than just misfire codes. Mode $06 also stores all the accumulating data for these components and systems—data that hasn’t quite reached the threshold to set a trouble code.
Exhaust Gas Sensor Monitor
Catalyst Monitor
EGR Monitor
VVT Monitor
EVAP Monitor
Exhaust Gas Sensor Heater Monitor
Heated Catalyst Monitor
Secondary Air Monitor
Fuel System Monitor
Boost Pressure Control Monitor
NOx Adsorber Monitor
NOx/SCR Catalyst Monitor
Misfire Cylinder Data
PM Filter Monitor
Here’s a Practical Example Of How Using Mode $06 Can Help You Diagnose
Consider a vehicle that has been failing its emissions test. The CEL is not illuminated, and there are no stored DTCs. By accessing Mode $06 data, a technician can review the results of the emissions-related tests done so far. They might discover that the catalytic converter efficiency is just below the acceptable threshold, indicating it’s not performing optimally. With this information, the technician can recommend replacing the catalytic converter, even though it hasn’t completely failed yet, ensuring the vehicle passes the emissions test.
OBD-II comprises several modes, each designed for specific diagnostic tasks:
- Mode $01: Displays current powertrain diagnostic data.
- Mode $02: Shows freeze frame data at the time a diagnostic trouble code (DTC) is set.
- Mode $03: Retrieves stored DTCs.
- Mode $04: Clears DTCs and resets certain monitors.
- Mode $05: Monitors oxygen sensor performance.
- Mode $06: Monitors results for non-continuous tests.
- Mode $07: Retrieves pending DTCs.
- Mode $08: Controls onboard system, test, or component.
- Mode $09: Requests vehicle information (e.g., VIN).
- Mode $0A: Retrieves permanent DTCs.
Mode $01: Monitor Status and Current Data
Mode 1 tells you the status of the readiness monitors. Each readiness monitor is associated with a system or component on the car that affects emissions. Readiness monitors are either continuous or non-continuous.
Continuous monitors are the Comprehensive Component monitor, the Misfire monitor and the Fuel monitor. All the other readiness monitors are non-continuous.
Each readiness monitor conducts a battery of tests to determine the health of that system or component. The readiness monitor simply tells you whether all of the tests for that monitor have run to completion.
Mode $02: Freeze Frame
Mode 2 is basically a recording function that stores the available data parameter I.D.s (PIDs) that are in the ECM at the same time it set a DTC. For example, the freeze frame data from a misfire trouble code can tell you the RPM, engine load, fuel trims and sensor readings that were present when the code set.
Mode $03: Stored Diagnostic Trouble Codes
Mode 3 is simply a stored list of trouble codes that have set and turned on the check engine or Malfunction Indicator Lamp (MIL). It’s what most users think a scan tool is for. Once a code has set, the ECM will continue testing. If the continuous testing shows that a once failed code now pass for three consecutive tests, the ECM will turn off the MIL.
However, the code will continue to be stored in Mode 3 as a history code. After a specified number of warm-up cycles with no recurrence, the code will be erased from memory.
Mode $05: Oxygen Sensor Monitor Test Results
Mode 5 contains the test results the ECM stored for verifying the proper operation of the oxygen sensors.
Mode $06: Non-continuous Monitor Test Results
Mode 6 is lists the individual tests and their results for every non-continuous monitor that has reached the threshold to set a trouble code. Most aftermarket service information systems list the test identifications and descriptions, making Mode 6 more friendly and more valuable.
Mode $07: Continuous Monitor Test Results or pending codes
Mode 7 is where you’ll find the records for trouble codes for systems or components that have failed once and require two fails to actually set the code. So, in effect, the trouble code is “pending” just waiting for a second fail. If you find a pending code, look up the freeze frame data for that pending code and then recreate the driving conditions to try and force a second failure.
Mode $08: Request Control Of Onboard Systems
In OBDII, only the EVAP system works with Mode 8 and then only on some models. Mode 8 allows you to command the EVAP system to seal itself by closing the canister vent valve, allowing you to then vacuum or pressure test the system for leaks.
Mode $09: Vehicle Information
Mode 9 provides the Vehicle Identification Number (VIN), and the ECM’s calibration information. This important data to determine whether the software in the vehicle is up to date.
How to use Mode $06 information to get a diagnosis
Let’s say your car maker requires a 500 misfire threshold on a single cylinder before it sets a cylinder related misfire code. The vehicle isn’t running right and you don’t have a check engine light or any stored or pending trouble codes. That’s where you head to Mode $06. Examine the data for each cylinder and see which cylinders have misfires and how many are stored.
©, 2019 Rick Muscoplat
Posted on by Rick Muscoplat