How to Diagnose a No-Crank, No-Start With Lost ECM Communication
The full system scan came back with 17 DTCs, most of them active. The Parktronics module, transmission control module and ABS all reported lost communication with the engine control module. The ABS even set a configuration mismatch, because it had nothing to compare its data against.
So Keith Perkins of Motor Age pulled up the topology map on the Autel MaxiSYS Ultra S2, selected the silent ECM and used ping network to ping it over and over while he wiggle-tested the harness. If a broken wire or loose ground were to blame, a response would show exactly where.
857 pings later: nothing.
That moved the diagnosis to the PCM connector itself. With breakout leads and the tool's four-channel oscilloscope, Perkins checked both powers, the ground, CAN high and CAN low on a single screen. What the scope showed decided the repair.
Watch the Tech Tip to see what the scope found, then visit autel.us/product/maxisys-ultra-s2 for more information.
About the Author
Keith PerkinsKeith Perkins
Keith Perkins has been in the industry for over 19 years, serving in various capacities, including engine machinist and assembler, dyno tuner, diagnostic technician, instructor, technical information specialist, repair technician, and many more roles through the years.
Currently, Perkins co-owns and operates the L1 Automotive Group with his wife. The L1 Automotive Group is comprised of three companies: L1 Automotive Diagnostics and Programming, Level 1 Automotive, and L1 Automotive Training.
Perkins currently holds the title of ASE Master Certified L1 Technician and ASE certifications A1-A9, L1, L4, X1, P2, xEV Level 2, and various other industry certifications. He also serves as a Subject Matter Expert for the ASE A1, A2, A7, A8, L1, and L4 tests.
Perkins has served on the Board of Directors for NASTF since 2023. He enjoys spending time with his wife of 18 years, Liz, and his two daughters, Rylynn and Bailey, in his off time. His favorite non-automotive activity is skydiving!
