The 2015 RLX is Honda's luxury flagship built on a reliable platform, but specific issues plague the 9-speed ZF transmission and the Sport Hybrid's complex AWD system. Most catastrophic problems stem from transmission fluid neglect or rare engine internal failures tied to piston ring defects.
9-Speed ZF Transmission Shudder and Overheating
Common · high severityTypical onset: 40,000-80,000 mi
Symptoms: Harsh shifting between 2nd-3rd gears during light acceleration, Transmission shudder at 25-40 mph, Check engine light with P0711 (transmission fluid temperature sensor), Delayed engagement from Park to Drive after warm-up
Fix: ZF9HP requires complete fluid flush with Honda ATF-DW1 (not generic fluid), external oil cooler replacement common. If torque converter is damaged from overheating, expect transmission removal and rebuild. 8-14 hours labor for cooler and fluid service; 18-24 hours for internal rebuild.
Estimated cost: $800-1,200 for cooler/flush; $4,500-6,500 for rebuild
Sport Hybrid SH-AWD Rear Motor Failure
Occasional · high severityTypical onset: 60,000-100,000 mi
Symptoms: SH-AWD warning light illuminated, Loss of rear-wheel torque vectoring, Grinding noise from rear differential area during acceleration, Limp mode with reduced power
Fix: Twin rear electric motors (TMUs) can fail due to bearing or inverter issues. Requires complete rear differential assembly removal. Honda typically replaces entire unit, not individual motors. 12-16 hours labor plus expensive hybrid components.
Estimated cost: $5,000-8,500
J35Y V6 Piston Ring and Cylinder Scoring
Rare · high severityTypical onset: 50,000-90,000 mi
Symptoms: Excessive oil consumption (1 qt per 1,000 mi or worse), Blue smoke on cold start, P0300-P0306 misfires across multiple cylinders, Loss of compression on cylinder leak-down test
Fix: Early J35Y6 engines had piston ring land defects causing blow-by and scoring. Requires complete short block replacement or full rebuild with updated pistons/rings. 24-32 hours labor for short block swap, more for full rebuild with machine work.
Estimated cost: $6,000-9,500
Jewel Eye LED Headlight Moisture and Ballast Failure
Common · low severitySymptoms: Condensation visible inside headlight lens, One or more LED elements not illuminating, Flickering on startup, AcuraLink warning for headlight malfunction
Fix: Honda issued recall 16V-574 for this, but many units still fail post-repair. Headlight assemblies have poor seals; ballast modules corrode. Dealer-only part, complete assembly replacement required. 2-3 hours per side.
Estimated cost: $1,800-2,500 per headlight assembly
Fuel Pump Module Failure (Low Pressure Pump)
Occasional · medium severityTypical onset: 70,000-110,000 mi
Symptoms: No-start condition after sitting overnight, Engine cranks extended before firing, Stumble or hesitation under hard acceleration, P0087 fuel rail pressure too low
Fix: In-tank low-pressure pump (part of sender assembly) fails, starving high-pressure pump. Related to recall 18V-355 but not all VINs covered. Tank drop required. 4-6 hours labor.
Estimated cost: $900-1,400
Lower Transmission Mount Collapse
Common · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Clunk when shifting from Reverse to Drive, Vibration at idle in Drive with brake applied, Visible forward/aft engine movement during throttle application, Rubber mount visibly separated or torn
Fix: Hydraulic lower mount (torque mount) fails from heat and stress, especially on hybrid models with extra weight. Requires subframe access. 2.5-3.5 hours labor.
Estimated cost: $400-650
Buy the base V6 with service records showing religious transmission fluid changes; avoid Sport Hybrid unless you can afford $8k repair bills and don't mind complexity.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.