ericthomasswenson
commented
3 years ago Dear Paul and Dan,
The recommended text for DM26 in Part 2 Test 8 builds upon the recommended revisions for part 1. The failure criteria not impacted by the change to KOER are repeated. The monitor complete failure criteria from part 1 was retained as an informative message. Checking for differences from part 1, was a conceptual error as improved monitor performance in recent MY engines has resulted in monitor completion, that is detected as a failure.
The recommended text is:
6.2.8 DM26: Diagnostic Readiness 3 6.2.8.1 Actions a. DS DM26 [send Request (PG 59904) for PG 64952 (SPs 3301-3305)] to each OBD ECU. i. Record time since engine start (SP 3301) from each ECU and timestamp of when message was received. b. Display monitor readiness composite value in log for OBD ECU replies only.
// In KOER mode, checking for differences in a KOEO Part 1 DM26 response is a conceptual error. // Invariant conditions from Part 1 still apply and can be checked, except for monitors that may complete KOER. // Enabled and Disabled bit values are not checked in Part 1 for supported monitors and need not be checked in Part 2.
6.2.8.2 Fail Criteria a. Fail if any response for each monitor not supported in DM5 by a given ECU is also reported in DM26 as “1=monitor not complete this monitoring cycle” in SP 3303 bits 5-7. // Unsupported monitors will never need to run and are ‘de facto’ complete. b. Fail if any response for each monitor not supported in DM5 by a given ECU is also reported in DM26 as “0=monitor enabled for this monitoring cycle” in SP 3303 bits 1 and 2 and SP 3304. [ // Unsupported monitors will never run and cannot be enabled. c. Fail if any response from an ECU indicating support for CCM monitor in DM5 reports “0=monitor disabled for rest of this cycle or not supported” in SP 3303 bit 3. d. Fail if any ECU reports number of warm-ups SCC (SP 3302) greater than zero. [33] e. Fail if NACK not received from OBD ECUs that did not provide a DM26 response to global query.
6.2.8.3 Warn Criteria
a. Warn, if any individual required monitor, except Continuous Component Monitoring (CCM) is supported by more than one OBD ECU.
b. Info, if any response for any monitor supported in DM5 by a given ECU is reported as “0=monitor complete this cycle or not supported” in SP 3303 bits 1-4 and SP 3305 [except comprehensive components monitor (CCM)].
// After a reset (here engine start), all completed monitors are reset to not complete. Some may complete under KOEO conditions.
This proposal will address the following observation from the new 3.0.7 release Start Test 2.8 - DM26: Diagnostic readiness 3
12:05:16.5114 Destination Specific DM26 Request to Engine #1 (0) 12:05:16.5144 18EA00F9 [3] B8 FD 00 (TX) 12:05:16.5229 18FDB800 [8] 43 00 00 37 60 1C E0 1E DM26 from Engine #1 (0): Warm-ups: 0, Time Since Engine Start: 67 seconds FAIL: 6.2.8.2.a - Difference from Engine #1 (0) monitor support bits this cycle compared to responses in part 1 after DM11.
... Suggest removing 6.2.8.2a check for failure evaluation.
Sincerely Yours,
Eric Swenson
False failures have been observed in Part 2 Test 8, when monitors complete under KOER conditions.
// In KOER mode, checking for differences in a KOEO Part 1 DM26 response is a conceptual error. // Invariant conditions from Part 1 still apply and can be checked, except for monitors that may complete KOER. // Enabled and Disabled bit values are not checked in Part 1 for supported monitors and need not be checked in Part 2.
Current draft text was in error — this is thus a future enhancement.
Details are shown below.