Lyriq Starting Failure Linked to Terminal 30 Issues

Working on a 2020 Cadillac ELR, I encountered nearly identical symptoms. The intermittent starting issues pointed to more than just a basic battery problem. After extensive testing, the root cause was traced to a faulty wiring harness connection near the main power distribution box. The voltage drop across Terminal 30 is often a telltale sign of a deeper electrical fault rather than just battery health. In these electric vehicles, the high-voltage system can mask underlying 12V system issues. The main culprit in my case was corrosion at a primary connection point, creating resistance in the ignition switch circuit. The fix required: Complete electrical system diagnostic, Replacement of degraded wiring harness sections, Cleaning and reseating multiple connection points, Reprogramming of power management module This was a serious repair that took several days to properly diagnose and fix. The symptoms you describe match the pattern of a wiring harness issue rather than a simple battery problem. The fact that your battery tested good but problems persist strongly suggests checking the entire power distribution path. Recommend getting a specialized EV technician to perform a complete voltage drop test across all major connection points in the Terminal 30 circuit.

Thanks for sharing your experience with the ELR electrical issues. Your solution involving the wiring harness definitely matches my symptoms. After reading this, I scheduled a visit with an EV-certified shop to do that complete voltage drop test you mentioned. The starter motor issues are really concerning since its my daily driver. Could you share what the repair ended up costing you? Also curious if youve had any electrical faults pop up since getting it fixed? Want to know what Im potentially looking at both cost and reliability wise.

Happy to report my repair journey had a positive outcome. The total bill came to 290€ which covered diagnosing and fixing the heavily discharged battery, much simpler than initially expected. The main charging system issue was resolved by correcting the Terminal 30 continuous plus connection, which had been causing the intermittent power supply problems. Since the repair, the starter motor has been functioning perfectly with no electrical faults recurring. The short circuit we originally suspected turned out to be unrelated to the core issue. The ignition switch and all associated components are now working as intended. The key was having a proper diagnostic performed by technicians who understood the complexities of EV electrical systems. While my repair ended up being straightforward, its still worth having them perform that voltage drop test youre planning, just to rule out any wiring harness complications. Based on your symptoms, you might be looking at a similar repair scope and cost range, though each case can vary depending on the exact fault found during diagnosis.

Found out what was wrong with my Lyriq today. Had that voltage drop test done at the shop and turns out the charging system had multiple issues. The circuit breaker was triggering out of nowhere) due to a degraded wiring connection, which explained the starting problems. The repair took about 4 hours and cost 340€. They found corrosion building up on several electrical connection points and had to replace a section of the wiring harness. The mechanic showed me where the short circuit was occurring, pretty much exactly where you described in your ELR. Since getting it fixed yesterday, the starter motor kicks in perfectly every time. No more power cutting out at Terminal 30. They also cleaned all the major connection points as preventive maintenance. The electrical fault codes are all cleared now. Really glad I took your advice about getting it properly diagnosed instead of just assuming it was a basic battery issue. Having a specialist EV shop handle it definitely made the difference in getting it fixed right the first time.