I/M Solutions Schaumberg, IL May 5-8, 2013

Issue Statement A number of state I/M programs are interested in performing OBD tests on diesel vehicles ≤ 14,000 lbs. GVWR Current gasoline readiness criteria will not work for diesel vehicles because of hard-to-set readiness monitors With EPA funding and participation, a workgroup was formed to focus on developing methods for addressing readiness when testing these vehicles The workgroup did not look into the issues of SIP credit for diesel testing nor the effectiveness of diesel OBD testing in identifying environmentally beneficial repairs The resulting document is a product of the workgroup and does not constitute official EPA guidance

States MA, NY, NJ, UT, CA Industry GM, Ford, Cummins, Volkswagen, BMW, Mercedes Associations EMA, Auto Alliance Facilitator ERG Government EPA

The aim of the workgroup was to produce a “Best Practices Document” (BPD) outlining the issues and options related to OBD testing of OBD-equipped diesel vehicles, with a focus on readiness The BPD is limited to MY1997+ OBD equipped diesel vehicles ≤ 14,000 GVWR This GVWR range covers light-duty (≤ 8,500 GVWR) and medium-duty (>8,500 and ≤ 14,000 GVWR) vehicles.

For gasoline vehicles, readiness is a bigger issue for the oldest OBD MYs; for diesels, the newest. For gasoline vehicles, EPA allows vehicles to pass with 1-2 “not ready” monitors if there are no DTCs commanding the MIL on. Readiness Exceptions List with work-arounds ( Similar strategies can be employed for diesel OBD if the state’s software has this flexibility and if diesel testing states gather the data needed to populate a diesel readiness exceptions list. There are also strategies related to newer OBD capabilities like permanent DTCs, which are discussed in the following slide.

There are 2 types of Diagnostic Trouble Codes (DTCs): Regular and Permanent, the latter of which is available on newer gasoline and diesel vehicles. Regular DTCs are used by original OBD systems to identify malfunctioning components; they can be erased by disconnecting the battery or via scan tool. Permanent DTCs (P-DTCs), which were implemented in MY , can only be erased by the OBD system itself and cannot be erased with scan tools or by disconnecting the battery. When a regular DTC commands the MIL on a P-DTC is also created and written to non-volatile memory (NVRAM) The storage of P-DTCs in NVRAM helps deter and detect the fraudulent clearing of DTCs.

OBD readiness monitors There are 11 readiness monitor bits in a diesel OBD system, which is the same number as in a gasoline OBD system. For diesel vehicles, only nine of the eleven readiness monitor bits are actually assigned to monitors at this point. Also, the monitor descriptions are different for MY2010 and newer diesel vehicles to reflect the use of different emission controls. Some diesel readiness monitors are hard to set because they are tied to a PM filter regeneration NMHC catalyst (#4) NOx/SCR aftertreatment (#5) PM filter (#10)

The following testing protocols should be treated the same for diesel OBD as for gasoline OBD: Diagnostic link connector (DLC) issues such as "missing,” “tampered,” or “malfunctioning DLC” “Failure to communicate,” pending DTCs, DTCs with no MIL illumination, and/or a MIL commanded on with no DTCs. Fraud and tampering detection. Communication protocols Therefore, the hardware and software currently in use for gasoline OBD I/M testing should also be able to communicate with the LDD and MDD vehicles.

Finally, states considering OBD testing of diesel vehicles should evaluate the effectiveness of their current method for identifying vehicle “fuel type” to ensure vehicles will be tested using the right procedure. Methods may include enhanced VIN decoding and/or completing additional OBD requests Recognize that MY compliant dates are now being studied as a quantum mechanical phenomena with Heisenberg Uncertainty properties.

By MY , 100% of all vehicles and engines should have P-DTCs. If the state’s test equipment can access P-DTCs and the test vehicle supports them, then P-DTCs should be used with readiness status and criteria such as distance traveled and/or number of warm-ups since DTCs cleared to make a readiness determination. P-DTC Option Steps Vehicle presented for testing and MIL is not commanded on. Scan tool will query OBD system to determine if the vehicle is P-DTC equipped. If the vehicle is P-DTC compliant and there are P-DTCs stored the vehicle fails the readiness check. If there are no P-DTCs stored and there are ≤ 1 unset readiness monitor, the vehicle passes the readiness check. If there are ≤ 2 unset readiness monitors, the vehicle will pass the readiness check if the distance since last code clear is > 500 miles and the number of warm-ups since code clear (wu-scc) is ≥ 30. (2 weeks) If neither of the two previous conditions are met, the vehicle should be checked to see if it is on a readiness exceptions list and then treated accordingly. If the vehicle is not on a readiness exceptions list, it should fail the readiness check.

If the test equipment or vehicle do not support P-DTCs then the procedures below may be implemented. If the vehicle has ≤1 monitor not ready, then the vehicle passes the readiness determination. If the vehicle does not meet this criterion, then: If there are 2 unset readiness monitors, it should be determined if both monitors are among the hard to set group of PM Filter, NOx/SCR Aftertreatment or NMHC Catalyst. If both unset readiness monitors are in this group and the distance since last code clear is > 750 miles and the number of warm-ups since code clear (wu-scc) is ≥ 45, the vehicle should pass the readiness check. (3 weeks) If neither of the two preceding criteria are met the vehicle should be checked to see if it is on a readiness exceptions list and then treated accordingly. If the vehicle is not on a readiness exception list, it should fail the readiness check.

MA- Paul Davis, Craig Woleader UT- Joe Thomas, Chris Woodhave Cummins- Greg Pataky VW- Bob Gruszczynski, Volker Lantzsch GM- Chris Brown At this time MA & NY are actively collecting data on these vehicles. Workgroup Members Here at IM Soln.

Additional Information

The value of 2 unset monitors in the hard to set group was chosen based on an analysis of existing data from MA Using 2 unset monitors (regardless of which ones they were) instead of 1 resulted in LDD vehicle Make/Model categories with initial not ready rates in the range of 0-9%. Using the ≤1 criteria resulted in initial not ready rates in the range of 0-13%. The overall MDD initial not ready rate fell from 7% to 3% with the ≤2 criteria. This analysis is based on 5,817 LDD and 3,232 MDD initial OBD tests performed on MY vehicles collected in

Distance driven targets The 500 & 750 mile figures are based on an estimated annual driving distance of 12,000, or 1,000 miles per month. It is anticipated a vehicle will be driven on average about 500 miles in two weeks and 750 miles in three weeks. The vehicle owner should be instructed that normal operation on both city and highway routes is most effective in setting readiness monitors.

Warm-up since last code clear targets The value of 30 warm-up cycles is based on an assumed average of 2 warm-up cycles per day or 14 per week. The workgroup recommends using 30 warm-up cycles to represent an average for a two week period and 45 warm-up cycles for a three week period.