2020 Toyota Highlander Check Engine Light in Murray, UT

It means your Highlander’s computer stored an OBD-II fault code identifying an engine or emissions system issue.

The 2020 Toyota Highlander uses onboard diagnostics to flag problems ranging from a loose gas cap (EVAP) to sensor faults or misfires. A precise code and freeze-frame data help our technicians determine whether it’s minor or requires immediate attention. In Murray’s temperature swings, EVAP and cold-start related codes are common.

• OBD-II code points to the affected system, not the exact failed part
• Common causes: EVAP leaks, O2 sensors, MAF issues, misfires, catalytic efficiency
• Schedule a scan and diagnosis online: schedule service

Frequent causes include EVAP leaks, oxygen sensor faults, MAF sensor issues, misfires (P0300–P0306), and catalytic converter efficiency codes (P0420).

On the 3.5L V6, small EVAP leaks (often gas cap related) and aging O2 sensors are typical. A dirty MAF can skew fuel trims, and neglected misfires risk damaging the catalytic converter. The exact repair depends on test results, not just the code name.

• EVAP small leak: inspect cap/seals and purge/vent circuits
• O2/AF sensors: verify with live data before replacement
• Misfire diagnosis: coils, plugs, injectors, compression as needed

If the light is steady, drive cautiously to service; if it’s flashing, stop driving to avoid catalytic converter damage from a severe misfire.

A steady light usually signals a non-urgent emissions fault, but you should still diagnose it soon to prevent costlier repairs. A flashing light indicates active misfire that can overheat and melt the catalyst. If unsure, reduce load and schedule an inspection promptly in Murray.

• Flashing = tow recommended; steady = short trips OK
• Avoid heavy acceleration or towing until checked
• Book a diagnostic: schedule appointment

A parts store can read a generic code for free; a Toyota dealer performs full diagnosis with Toyota Techstream, OEM test plans, and isolation testing.

Code readers show symptoms, not causes. Our factory-trained technicians access proprietary data, bi-directional tests, and service bulletins to confirm the fault before any repair. This reduces parts guessing and provides a written estimate aligned to Toyota repair procedures for the Salt Lake Valley.

• Techstream access: freeze-frame, live PIDs, active tests
• Guided diagnostics per Toyota service information
• Written estimate before work; check service specials

No—resetting clears OBD-II readiness monitors, and your Highlander will likely fail until monitors complete drive cycles.

Utah’s inspections check for stored codes and readiness. Clearing the light hides the fault temporarily but resets monitors to “Not Ready,” which triggers a fail on many stations. A verified repair followed by successful monitor completion is the correct path to a pass.

• Complete monitors require specific driving conditions
• Fix the root cause to avoid repeated failures
• Get a diagnostic plan: schedule service

Yes—a loose or damaged gas cap can set EVAP small-leak codes and turn on the light.

If you recently refueled in Murray or Salt Lake City, re-seat the cap until it clicks and drive several cycles to see if the light clears. If it persists, we’ll smoke-test the EVAP system and inspect purge/vent valves and lines for leaks typical in seasonal temperature swings.

• Inspect cap seal for cracks or deformation
• EVAP smoke test locates tiny leaks quickly
• Check our service specials before booking

LHM Toyota Murray serves drivers across the Salt Lake Valley, including Salt Lake City, Sandy, West Jordan, South Jordan, Millcreek, Holladay, and Taylorsville with diagnostic expertise tailored to the 2020 Toyota Highlander. Factory scan tools such as Toyota Techstream provide access to proprietary data, guided tests, and calibrations that generic OBD-II readers can’t perform. That matters in Northern Utah’s climate, where cold starts and big temperature swings often trigger EVAP and fuel-trim related codes. Our process focuses on confirming the fault before parts are replaced, minimizing guesswork and unexpected add-ons. Visit our modern service center at 5650 South State Street for clear findings, a written estimate, and repairs aligned to Toyota procedures. Need directions or ready to book? Use our online portal to schedule service or check current service specials.

Your visit starts with an initial OBD-II scan and retrieval of freeze-frame data from the 2020 Toyota Highlander’s engine control module. A technician then performs targeted visual checks and isolation tests based on the code family (EVAP, fuel trim, misfire, sensor circuit, or catalyst efficiency). Live data review, smoke testing for EVAP leaks when indicated, and circuit checks help confirm the root cause before any repair authorization. You’ll receive a written estimate outlining verified findings and recommended next steps, so you can decide with confidence. If the concern is intermittent, we note conditions and may perform drive-cycle verification. Ready to proceed or just want clarity? Check our service specials and schedule service online.

Highlander owners most often encounter codes such as P0456/P0442 (small EVAP leak), P0138/P0158 or A/F sensor range/performance (oxygen/air-fuel sensors), P0171 (system too lean), P0300–P0306 (random/single-cylinder misfire), and P0420 (catalyst system efficiency below threshold). EVAP leaks can be as simple as a cap seal, while sensor and fuel-trim issues may indicate intake leaks or MAF contamination. Misfires left unchecked can overheat and damage the catalytic converter, turning a modest repair into a major expense. Ignoring catalyst efficiency faults can also impact fuel economy and emissions test results. Timely diagnosis protects your 3.5L V6 and prevents secondary failures. Bring your 2020 Toyota Highlander to Larry H. Miller Toyota Murray in Murray for an accurate diagnosis — schedule service.