The California Clean Truck Check program requires heavy-duty trucks to pass an On-Board Diagnostic (OBDII) inspection. Is your truck ready? This article explains the Obdii Scanner Ready requirements and how to ensure your vehicle passes.
Understanding OBDII Scanner Ready Status
OBDII systems monitor vehicle emissions components. When a problem is detected, a warning light illuminates, and the system stores diagnostic trouble codes (DTCs). To accurately assess emissions, the OBDII system must complete a full diagnostic cycle, achieving “OBDII scanner ready” status.
Resetting the system, such as by disconnecting the battery or using a scan tool, clears these codes and requires the system to re-run its diagnostics. This process requires sufficient vehicle operation to achieve readiness again.
Clean Truck Check OBDII Requirements: What Does “OBDII Scanner Ready” Mean?
The Clean Truck Check program is phasing in OBDII readiness requirements. Currently, a vehicle needs at least five (5) warm-up cycles (WUCs) since the last code clearing to be considered OBDII scanner ready. A “Not Ready” result means non-compliance with emissions regulations.
Affected Vehicles and OBDII System Purpose
The following vehicles are subject to OBDII testing:
- Heavy-duty diesel vehicles and diesel hybrids with 2013 and newer model year engines.
- Alternative fuel (e.g., natural gas) and alternative fuel hybrid heavy-duty vehicles with 2018 and newer model year engines.
The OBDII system:
- Monitors emission control system effectiveness.
- Identifies components needing repair.
- Alerts the driver to problems.
- Aids technicians in diagnosis and repair.
- Promotes durable emission control system design.
Ensuring Your Truck is OBDII Scanner Ready
To maximize your chances of passing:
-
Address any illuminated Malfunction Indicator Light (MIL) immediately.
-
Test early in the compliance window to allow time for repairs and retesting.
-
Avoid clearing codes. This resets the OBDII system and requires significant driving to regain readiness. Code clearing can occur from:
- Disconnecting the battery.
- Improperly installed kill switches that disconnect OBDII system power.
- Using an OBDII scan tool to clear codes.
-
Confirm test results appear in your CTC-VIS account within five minutes. If not:
- Retest your vehicle.
- Unplug devices connected to the diagnostic port.
- Verify communication between the vehicle and the OBDII test device.
- Ensure a stable internet connection.
-
Contact [email protected] for persistent issues.
Key Elements of the OBDII Test
The Clean Truck Check OBDII test evaluates:
- MIL status and associated DTCs.
- Monitor Readiness (OBDII scanner ready status).
- Operation Since Codes Cleared (OSC).
- Permanent Diagnostic Trouble Codes (PDTCs).
Monitor Readiness and Warm-Up Cycles
Monitor readiness indicates if the OBDII system has completed its diagnostic checks. Insufficient operation since the last code clearing results in a “Not Ready” status and a failed test. A code clear can occur after a repair or battery issue.
Various monitor groups assess different components. Examples include: Misfire, Fuel System, Catalyst, Exhaust Gas Sensor, and Particulate Matter Filter. Most trucks tested have ready monitors, but recently cleared codes will result in “Not Ready” status.
OSC data tracks vehicle operation since the last code clearing, including warm-up cycles (WUCs), distance traveled, and engine run time. Meeting minimum OSC thresholds is critical for passing.
A warm-up cycle involves driving until the engine coolant temperature rises by at least 40°F after starting and reaches at least 140°F for diesel engines (160°F for natural gas engines). Heavy-duty vehicles often require numerous WUCs, miles, and engine hours for complete readiness.
Permanent Diagnostic Trouble Codes (PDTCs)
PDTCs, unlike regular DTCs, cannot be cleared by disconnecting the battery or using a scan tool. They indicate a persistent emissions-related problem. Fixing the underlying issue and allowing sufficient drive time for monitor re-evaluation is the only way to clear a PDTC. The presence of a PDTC will generally result in a failed test.
PDTCs will be ignored if the vehicle demonstrates sufficient operation since the last code clearing, indicating the issue has likely been resolved. Specific OSC criteria for PDTCs will be phased in, starting in September 2024. These requirements will gradually increase in stringency.
Ensuring your truck is “OBDII Scanner Ready” is crucial for complying with the Clean Truck Check program. Proactive maintenance, avoiding unnecessary code clearing, and understanding the testing requirements are essential for a successful outcome. Refer to the official CTC regulations for complete information.
