09/20/2026
MINOR COLLISION IMPACT. NO-START CONDITION. ELECTRICAL SYSTEM FAILURE.
ARE THEY ALL RELATED?
Here is a case study of a recent diagnostic repair at our ADAS Lab.
This 2021 Nissan Maxima was towed to our facility from a collision shop with a no-start condition following a relatively minor right-rear impact.
What made this case interesting was the delay: the vehicle operated normally for several days after the collision before it suddenly would not start.
Initial testing found battery voltage dropping to approximately 5 volts with the ignition on. A complete scan was not possible because nearly every control module was offline. Our scan tool could communicate with essentially only the CAN gateway.
We found two open 10-amp fuses, including one supplying the vehicle gateway and shutting down network communication. When replaced, the fuse opened again every time the ignition was switched on. Resistance testing measured approximately 0.4 ohms to ground, confirming a direct short.
Using wiring diagrams, we traced the shared circuit into the rear bumper and trunk—exactly where the collision damage occurred. Behind the damaged bumper, we found the right-rear blind-spot radar hanging near the rear quarter. Its housing was cracked and the circuit board exposed. Disconnecting the radar did not eliminate the short, meaning another failure remained. Continued inspection revealed a melted junction connector and multiple heat-damaged wires. The damaged radar had shorted the shared circuit, damaging the body wiring harness and taking much of the vehicle network offline, and causing the no-start condition.
After isolating the damaged circuit and separating the melted wires, the fuse stopped opening and communication returned. With communication restored, the scan revealed 62 stored or active faults across multiple systems.
The collision facility then completed the body repairs and replaced the blind-spot radar and damaged body wiring harness. The vehicle returned to us for calibration and final verification, including the blind-spot verification test and Surround View system calibration.
The result:
✅ No-start condition resolved
✅ Communication network restored
✅ Replacement blind-spot radar tested
✅ Surround View system calibrated
✅ ADAS systems verified
✅ Faults successfully addressed
This case is an important reminder that collision severity cannot be judged by visible damage alone.
What looked like minor bumper damage involved a shorted blind-spot radar, damaged body wiring, a disrupted communication network and a complete no-start condition.
The damaged radar was the clue. Understanding everything connected to it was the diagnosis.