(4.6) Software Calibration Identification
(4.6.1) On all vehicles, a software calibration identification number (CAL ID) for the diagnostic or emission critical powertrain control unit(s) shall be made available through the standardized data link connector in accordance with the SAE J1979 specifications. Except as provided for in section (g)(4.6.3), for 2009 and subsequent model year vehicles, the OBD II system shall use a single software calibration identification number (CAL ID) for each diagnostic or emission critical powertrain control unit(s) that replies to a generic scan tool with a unique module address.
(4.6.2) A unique CAL ID shall be used for every emission-related calibration and/or software set having at least one bit of different data from any other emission-related calibration and/or software set. Control units coded with multiple emission or diagnostic calibrations and/or software sets shall indicate a unique CAL ID for each variant in a manner that enables an off-board device to determine which variant is being used by the vehicle. Control units that utilize a strategy that will result in MIL illumination if the incorrect variant is used (e.g., control units that contain variants for manual and automatic transmissions but will illuminate the MIL if the variant selected does not match the type of transmission on the vehicle) are not required to use unique CAL IDs.
(4.6.3) For 2009 and subsequent model year vehicles, manufacturers may request Executive Officer approval to respond with more than one CAL ID per diagnostic or emission critical powertrain control unit. Executive Officer approval of the request shall be based on the method used by the manufacturer to ensure each control unit will respond to a SAE J1978 scan tool with the CAL IDs in order of highest to lowest priority with regards to areas of the software most critical to emission and OBD II system performance.
(4.7) Software Calibration Verification Number
(4.7.1) All 2005[SUP]2[/SUP] and subsequent model year vehicles shall use an algorithm to calculate a calibration verification number () that verifies the on-board computer software integrity in diagnostic or emission critical powertrain control units. The shall be made available through the standardized data link connector in accordance with the SAE J1979 specifications. The shall be capable of being used to determine if the emission-related software and/or calibration data are valid and applicable for that vehicle and CAL ID. For 50 percent of 2010 and 100 percent of 2011 and subsequent model year vehicles, one shall be made available for each CAL ID made available and each shall be output to a generic scan tool in the same order as the CAL IDs are output to the scan tool to allow the scan tool to match each to the corresponding CAL ID.
(4.7.2) Manufacturers shall request Executive Officer approval of the algorithm used to calculate the . Executive Officer approval of the algorithm shall be based on the complexity of the algorithm and the difficulty in achieving the same with modified calibration values.
(4.7.3) The shall be calculated at least once per driving cycle and stored until the is subsequently updated. The stored value may not be erased when fault memory is erased by a generic scan tool in accordance with SAE J1979 specifications or during normal vehicle shut down (i.e., key off, engine off).
(4.7.4) When a request message is received by the on-board computer, the stored value shall be made available through the data link connector to a generic scan tool.
(A) Except as provided below in sections (g)(4.7.4)(B) and (C), when a request is received, the on-board computer may not respond with negative response codes (i.e., may not use delayed timing in sending the and may not respond with a message indicating the value is not currently available) and may not respond with a default value. Default value is defined as any value or space holder that is not a valid value.
(B) If the request message is received within the first 120 seconds of vehicle operation after a reprogramming event or a non-volatile memory clear or within the first 120 seconds of vehicle operation after a volatile memory clear or battery disconnect, the on-board computer may respond with a negative response code directing the scan tool to wait or resend the request message after the delay. Such responses and delays shall conform to the specifications for transmitting data contained in SAE J1979.
(C) If a communication malfunction is preventing access to a value for reporting in response to a scan tool request, a default value may be reported in lieu of a valid value provided that:
(i) a pending fault code is stored or a confirmed fault code is stored with the MIL commanded on pinpointing a communication fault for the module that is unable to report a valid , and
(ii) the default value used cannot be mistaken for a valid (e.g., all zeros or all question marks for the default value).
(4.7.5) For purposes of Inspection and Maintenance (I/M) testing, manufacturers shall make the and CAL ID combination information available for all 2008 and subsequent model year vehicles in a standardized electronic format that allows for off-board verification that the is valid and appropriate for a specific vehicle and CAL ID. The manufacturer shall use the most recent standardized electronic format detailed in Attachment E: CAL ID and Data of ARB Mail-Out #MSC 06-23, December 21, 2006, incorporated by reference. Manufacturers shall submit the and CAL ID information to the Executive Officer not more than 25 days after the close of a calendar quarter.
(4.8) Vehicle Identification Number:
(4.8.1) All 2005 and subsequent model year vehicles shall have the vehicle identification number (VIN) available in a standardized format through the standardized data link connector in accordance with SAE J1979 specifications. Only one electronic control unit per vehicle shall report the VIN to an SAE J1978 scan tool.
(4.8.2) If the VIN is reprogrammable:
(A) For 2012 and subsequent model year vehicles not included in the phase-in specified in section (g)(4.8.2)(B) below, all emission-related diagnostic information (i.e., all information required to be erased in accordance with SAE J1979 specifications when a Mode/Service $04 clear/reset emission-related diagnostic information command is received) shall be erased in conjunction with the reprogramming of the VIN.
(B) For 30 percent of 2019, 60 percent of 2020, and 100 percent of 2021 and subsequent model year vehicles, if the VIN is reprogrammable, in conjunction with reprogramming of the VIN, the OBD II system shall erase all emission-related diagnostic information identified in section (g)(4.10.1) in all control modules that reported supported readiness for a readiness bit other than the comprehensive components readiness bit.