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Tuesday, 26 February 2019 21:59

ASA Webinar Features ‘G’ Jerry Truglia’s ‘Why a DTC is Not Always Displayed’

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Truglia explained that repairers can get factory scan tool capabilities with J2534 and LSID/VSP, and he encouraged everyone to sign up at nastf.org because “when you replace just about any computer on today’s vehicles, you’ll need that information to get the vehicle back online.”

Displaying a slide that showed the modes of the OBD II, Truglia pointed out that this is the powertrain data that everyone has been looking at for years. He emphasized the importance of Mode 6, Mode 9 and Mode 10.

 

“Mode 9 is super important because it gives us VIN information and allows us to see calibration files. Mode 10 will give us information that is stored in computer systems. This information is only erased after the vehicle has passed multiple times in special criteria,” he said.

 

Truglia proceeded to demonstrate how to use the scan tool’s different modes, providing examples of scans and discussing what each of them could mean.

 

Truglia explained, “If a monitor is not ready and you give the vehicle back to the customer without telling them, the client may get their check engine light illuminated again, and they won’t know whether it’s on for something they already paid to fix. I recommend that you print these screens and give them to the customer.”

 

Reminding everyone to use the generic/global OBD II first, Truglia noted that generic scan tools cannot substitute a value like an enhanced tool can. He talked through selecting the correct PIDs that should be viewed, pointing out that generic tools don’t have as many so they are less confusing.

 

Truglia then moved on to discussing scan data fuel trim and the importance of knowing the good and bad limits so imbalances in the engine can be identified. He walked through many examples and explained the different issues that can be identified with this data.

 

He noted, “Why does the number of fuel trim make a difference? Knowing which cell lets us know what and where to look for problems. Most mapping systems use a total of 16 cells, while some others will use a few more for other cells for fuel cut off, power enrichment, and EVAP purge, to name a few. Looking at RPM and map or load, you can see the difference of how we add or subtract fuel using fuel trim cell data.