Nissan LEAF 62 kWh “EV Service” Mystery — Battery Isolation Fault EXPOSED & Fixed! ⚡🔧

A Nissan LEAF ZE1 (2017+, 62 kWh) came in with the dreaded EV Service Warning / restart inhibited after power off. Range was fine, but the high-voltage isolation test failed. We proved the leak was inside the battery pack, dropped the pack, split banks, isolated the faulty 33 V module, replaced it, verified cell balance (7–15 mV), and road-tested. Final isolation test passed ✅ What we cover: ZE1 62 kWh pack architecture (12 modules, ~33 V each, ~350 V total) Correct isolation testing at the service plug & HV connectors Finding a leak to chassis and narrowing it to a single module Replacing one 33 V block, re-sealing, reassembly & BMS checks Transparent costs (pack £1200+VAT, labour £1500+VAT → £2700+VAT total) Final charge, drive test, autonomy & health We’re OGS Mechanics — Hybrid & EV (London). Real diagnostics, safe HV work, component-level fixes. 📍 Visit Us: OGS Mechanics Units 9–14, Millers Yard Rear of 28 Long Lane London N3 2QG 📞 07918 061897 📺 Watch Our Repairs in Action: 📌 Subscribe on YouTube → Weekly EV/Hybrid breakdowns, fixes & full diagnostics 📲 Follow the Behind-the-Scenes Garage Life: 🎵 TikTok: https://www.tiktok.com/@ogsmechanics 📸 Instagram: https://www.instagram.com/ogs_mechanics 📘 Facebook: https://www.facebook.com/share/15J54KFwjE/?mibextid=wwXIfr 🕒 Timestamps: 0:00 Intro — LEAF ZE1 62 kWh, EV Service Warning (restart inhibited) 1:05 Live scan: no drive errors, range OK — but hidden HV issue 2:20 Battery health & balance check (SoH ~95%, Δcells ~14 mV) 3:10 Isolation test at service plug — fault confirmed 4:20 Underbody HV connectors isolated — fault is internal to battery 5:40 Pack removal (why ZE1 is “easier”) 7:00 Opening the 62 kWh pack (sealant, cover, layout) 8:20 Splitting banks & busbars to locate the leaking module 10:05 The culprit: end module with leak under compression 11:10 Replacement 33 V block — voltage matching & balance checks 12:30 Reassembly: torque, busbars, BMS harness, isolation re-test 13:40 Reading BMS data — cell delta 7–15 mV (good) 14:30 Reseal, install, ready mode & road test 16:00 Final isolation test passed, no warnings 16:40 Costs & recap — why not to replace a whole pack by default #NissanLeaf #ZE1 #Leaf62kWh #EVServiceWarning #IsolationFault #HighVoltageBattery #BMS #EVRepair #ElectricCarRepair #BatteryPack #OGSMechanics #WorkshopLife