A 2013 Chevy Silverado Z71 presented with a no RPM reading, long crank time, and misfires on cylinders 3 and 8. After confirming good compression and fuel injector pulse, the focus shifted to the lack of RPM signal and long crank. A new starter, crank and cam sensors, and cam sensor harness had already been installed.
Initial diagnostics included checking all fuses and verifying the scan tool (Autel) showed no RPM in most engine menus. However, the crank sensor data within the ignition sub-menu did display an RPM signal, indicating the crank sensor was communicating with the PCM.
Wiring and terminals from both the crank and cam sensors to the PCM (via the X2 connector) were checked for continuity, corrosion, and looseness. All tested good. The fuse block was also inspected for damage, with no issues found. Furthermore, the scan tool confirmed healthy 5V Ref-1 and 5V Ref-2 circuits, ruling out obvious voltage supply problems.
A key question arose concerning the source of the DLC’s RPM data: does it come directly from the PCM or indirectly via the instrument cluster? Understanding the complete operational description of both crank and cam sensor circuits is crucial for further diagnosis. One theory suggests the crank sensor provides timing for cylinder 1, while the cam sensor handles cylinders 2-8, but this needs verification within the vehicle’s documentation.
Next steps include a thorough review of the system wiring diagrams and sensor operation descriptions. This information will guide further testing and pinpoint the root cause of the no RPM signal, long crank time, and misfires. A professional-grade 2015 Chevy Silverado Scan Tool capable of bi-directional communication and in-depth data analysis will be essential for efficient troubleshooting.
While a 2015 Chevy Silverado scan tool is valuable for retrieving diagnostic trouble codes (DTCs), the absence of an RPM signal might necessitate a deeper dive into sensor data, wiring diagrams, and component testing.
A comprehensive understanding of the system’s operation, combined with a powerful scan tool and methodical troubleshooting, are key to resolving this complex issue. Using a high-quality 2015 Chevy Silverado scan tool will expedite diagnosis and help ensure accurate repairs.
