Used Car Pre-Purchase Technical Inspection: Paint Thickness, OBD-II Live Data & Mechanical Checks

Key Reference Specifications & Standards
Factory OEM Paint Thickness	90–160 µm (3.5–6.3 mils) exterior panels
Door Jambs & Pillars OEM	55–95 µm (interior structural zones)
Repaint / Body Filler	180–300 µm (second coat) · >350 µm (putty)
OBD-II PID $01 31	Distance traveled since DTCs cleared (target > 500 km)

Key Reference Specifications & Standards

Factory OEM Paint Thickness

90–160 µm (3.5–6.3 mils) exterior panels

Door Jambs & Pillars OEM

55–95 µm (interior structural zones)

Repaint / Body Filler

180–300 µm (second coat) · >350 µm (putty)

OBD-II PID $01 31

Distance traveled since DTCs cleared (target > 500 km)

1. Structural Pillars vs Cosmetic Panel Repainting

Always measure the roof first to establish the factory baseline (typically 90–140 µm on Japanese/Korean cars and 110–160 µm on European cars). Cosmetic respraying of a bumper or lower door (180–260 µm) is minor, whereas readings >300 µm on A/B/C pillars, rocker sills, or strut towers indicate structural collision repair.

2. Checking OBD-II Readiness Monitors & Distance Since Code Clear

A dark Check Engine Light on the dashboard is not enough. Connect an OBD-II scanner and read PID $01-01 (Readiness Monitors) and PID $01-31 (Distance traveled since codes cleared). If Catalyst, EVAP, or O2 monitors show 'Incomplete' and distance since clear is < 50 km, fault codes were erased right before your visit.