FTC Reader Disclosure: When you purchase or register through links on our site, we may earn an affiliate commission at no extra cost to you. Read our Editorial & Advertising Policy.
P0308LexusLexus Platform HubMaster P0308 GuideCritical Severity

P0308 on Lexus: Symptoms, Causes & DIY Fix

Official technical diagnostic wire for fault code P0308 (P0308: Cylinder 8 Misfire Detected (V8 Engine)) specifically affecting Lexus vehicles (ES, RX, NX, GX, LX).

DIY Parts Estimate
$140 - $520 (DIY: $35 - $110)
Lexus OEM Direct Fit
Shop Labor Quote
$180 – $380
Based on $135/hr labor
Drivability Status
Not Drivable
Critical urgency level
Est. DIY Time
45 – 90 Min
Basic hand tools
Check P0308 On Another Make:
ToyotaBMWMercedes-BenzLexusFordHyundaiCadillacTeslaChevroletHondaAudiNissanJeepKiaSubaruRAMGMCVolkswagenMazdaDodgeVolvoBuickLincolnChryslerAcura

1. Symptoms of P0308 on Lexus

When the Engine Control Module (ECM/PCM) on your Lexus logs fault code P0308, drivers commonly observe:

System alert or indicator light illuminated (P0308) on Lexus (ES, RX)
Intermittent performance throttling or unexpected operation halts on Lexus (ES, RX)
Audible sensor relay clicking or anomalous status telemetry in dashboard logs on Lexus (ES, RX)
Degraded operational throughput or error dialog popups on startup on Lexus (ES, RX)
Readiness monitors failing state emissions or system compliance audits on Lexus (ES, RX)

2. Most Likely Causes on Lexus

Historical warranty claims and technical repair bulletins for Lexus point to the following failure distribution:

55%
Component aging, oxidation, or degraded internal circuit element (Cylinder 8 Spark Plug / Coil) (Lexus OEM Part)
25%
Wiring harness abrasion, loose terminal pin, or ground voltage float (Lexus OEM Part)
12%
Outdated firmware microcode or incompatible software driver update (Lexus OEM Part)
8%
Thermal stress or excessive operational duty-cycle fatigue (Lexus OEM Part)
8%
Contamination from carbon buildup, moisture ingress, or dirty filtration (Lexus OEM Part)

3. Step-by-Step DIY Repair Guide for Lexus

01
Connect Diagnostic Scanner / Logging Monitor to Retrieve Telemetry

Interface with the diagnostic port or system console using verified scanning hardware. Record freeze-frame data, active sub-codes, and timestamps to isolate whether P0308 is static or intermittent. on Lexus vehicles (ES, RX).

Required Tool: Deep spark plug socket, Ratchet
02
Perform Physical & Electrical Circuit Inspection

Visually inspect the physical component (Cylinder 8 Spark Plug / Coil), connector pins, and associated wiring harnesses for signs of corrosion, thermal melting, or loose grounding clips. on Lexus vehicles (ES, RX).

Required Tool: Multimeter, Flashlight, Contact Cleaner Spray
03
Component Testing & Resistance / Voltage Verification

Measure reference voltages and resistance thresholds against manufacturer factory specifications. Replace any component failing nominal impedance tolerances. on Lexus vehicles (ES, RX).

Required Tool: Deep spark plug socket, Ratchet
04
Execute Component Replacement or Software Configuration Patch

Install genuine OEM replacement hardware or execute registry / service commands. Ensure all mounting bolts are torqued to factory specifications. on Lexus vehicles (ES, RX).

Required Tool: Standard Hand Tool Set / Terminal Commands
05
Clear Diagnostic Trouble Code & Complete Verification Drive Cycle

Erase the fault code from non-volatile memory. Perform a standard verification cycle (e.g. 15-minute mixed drive or system stress benchmark) to ensure monitors reset to 'Ready' state without recurrent fault flags. on Lexus vehicles (ES, RX).

Required Tool: OBD-II Code Reader / Diagnostic Suite

P0308 Guides by Lexus Model

Select your specific Lexus model below for exact OBD-II DLC port locations, wiring diagrams, and engine displacement specs:

Other Common Diagnostic Codes on Lexus

Troubleshoot other high-frequency Check Engine Light fault codes reported across Lexus vehicles:

4. Lexus P0308 FAQs

What causes code P0308 to trigger on a Lexus?

On Lexus vehicles, P0308 is most frequently caused by Component aging, oxidation, or degraded internal circuit element (Cylinder 8 Spark Plug / Coil) or Wiring harness abrasion, loose terminal pin, or ground voltage float. Factory sensor degradation or wiring harness wear near the engine bay are common factors.

Can I safely drive my Lexus with code P0308?

No. Immediate shutdown / repair required to prevent permanent hardware destruction or total system lockup. Given that P0308 carries a Critical severity rating on Lexus vehicles, we advise performing diagnostic scanning via the OBD-II port before extended driving.

How much does it cost to fix P0308 on a Lexus?

DIY replacement parts typically range between $140 - $520 (DIY: $35 - $110). If serviced at an authorized Lexus dealership, expect an additional $120–$250 in professional labor based on their $135/hr hourly rate.