2023 Lucid Air Pure

Lucid Air P0C73 Front Motor Position Sensor Fault After Wheel Bearing Replacement

P0C73 LDU_F_0x09 Published 2025-05-13 Updated 2025-05-13
Lucid Air P0C73 motor position sensor resolver wheel bearing front motor

2023 Lucid Air Pure presented with P0C73 front motor position sensor fault two days after a front wheel bearing replacement at an independent shop. Resolver reluctor ring had been damaged during bearing removal — improper press technique contaminated resolver air gap with metal particles.

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The Problem
2023 Lucid Air Pure (16,800 miles) presented with 'Drive System Fault' and P0C73 two days after a front wheel bearing replacement at a general automotive shop. Fault was intermittent initially, then permanent. Front motor torque completely disabled.
Diagnostic Procedure
  1. 1. Confirm P0C73 against front left drive unit. Resolver signal quality check: sine output amplitude correct, cosine output showing dropout at specific rotor positions — classic sign of reluctor ring damage affecting resolver accuracy at certain angles.
  2. 2. Review bearing replacement procedure at shop. Shop confirms they used a standard hydraulic press without a dedicated EV bearing adapter. Excess press force during bearing removal caused press jaw to contact the resolver reluctor ring, creating three indentations on the ring surface.
  3. 3. The indentations cause resolver signal dropout at the corresponding rotor angles, triggering P0C73 when those positions are encountered during motor operation.
  4. 4. Reluctor ring is integral to the front drive unit end cap on Lucid Air — not separately replaceable. Front drive unit replacement required.
  5. 5. Replace front drive unit assembly.
  6. 6. Post-replacement resolver signal: clean sine and cosine outputs throughout full 360° rotation. P0C73 cleared.
  7. 7. Test drive: full front motor torque restored, no fault return.
Resolution & Root Cause
Front drive unit replaced. Resolver reluctor ring damage confirmed as root cause. Full powertrain function restored.
💡 Key Lesson
Lucid Air wheel bearing service requires a dedicated EV-compatible press adapter that protects the resolver reluctor ring. A general hydraulic press without this adapter will contact and damage the ring during removal. P0C73 appearing days after bearing service — inspect the reluctor ring immediately. The damage is subtle (small indentations) but causes dropout at specific resolver positions and ultimately requires drive unit replacement.
About This Case

This case was solved remotely by an HVDesk specialist with 15+ years of hands-on experience across major EV platforms including Tesla, Hyundai/Kia, Volkswagen ID series, BMW i-series, and Ford EVs. The procedure was provided as structured remote support to an independent auto repair shop.