Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Mode, Selecting: Notes
The information provided in Modes 01 through 09 displays the various levels of emission related data that may be monitored, as well as the ability to retrieve and read stored DTC trouble codes, generate readiness codes, and select the various PIDs and Test-IDs used within the modes to monitor the engine, and emission related component parameters.
The following table provides a link to all diagnostic modes that monitor all components and systems which influence the emission quality.
Depending on scan tool and protocol used, the information in diagnostic mode 01 may be referred to by different names such as Test-ID (TID), Hex-ID, Component-ID (CID), or On-Board Diagnostic Monitor Identifier (OBDMID).
| Selectable Diagnostic Modes | |
|---|---|
| Diagnostic Mode 01 - Obtain Data DIAGNOSTIC MODE 01 - READ CURRENT SYSTEM DATA . | |
| Diagnostic Mode 02 - Obtain Operating Conditions DIAGNOSTIC MODE 02 - READ OPERATING CONDITIONS . | |
| Diagnostic Mode 03 - Interrogating Fault Memory DIAGNOSTIC MODE 03 - READ DTC MEMORY . | |
| Diagnostic Mode 04 - Reset/Delete Diagnostic Data DIAGNOSTIC MODE 04 - ERASE DTC MEMORY . | |
| Diagnostic Mode 06 - Check Test Results of Components that are not Continuously Monitored DIAGNOSTIC MODE 06 - READ TEST RESULTS FOR SPECIFIC DIAGNOSTIC FUNCTIONS . | |
| Diagnostic Mode 07 - Check Test Results of Components that are Continuously Monitored DIAGNOSTIC MODE 07 - READ FAULTS DETECTED DURING THE CURRENT OR LAST DRIVING CYCLE . | |
| Diagnostic Mode 08 - Tank Leak Test DIAGNOSTIC MODE 08 - REQUEST CONTROL OF ON-BOARD SYSTEM, TEST OR COMPONENT . | |
| Diagnostic Mode 09 - Vehicle Information DIAGNOSTIC MODE 09 - READ VEHICLE INFORMATION . |
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.