2020 Toyota Mirai Check Engine Light in Murray, UT

It means the Mirai’s OBD-II system stored a fault; a steady light signals a detected issue, while a flashing light indicates a severe misfire risk.

Your 2020 Toyota Mirai uses onboard diagnostics to monitor engine, fuel, and emissions systems. Many alerts are minor—like a loose fuel cap on the EVAP system—while others require prompt attention to protect components. In Murray, our Toyota scan tools read the code, freeze-frame data, and sensor status to pinpoint root cause, not just symptoms.

• Steady = schedule a diagnostic soon
• Flashing = stop driving and arrange service immediately
• OBD-II code identifies the system (e.g., EVAP, O2, misfire)

Frequent causes include EVAP leaks (loose gas cap), oxygen sensor faults, mass air flow issues, catalytic converter efficiency, or cylinder misfires.

While the Mirai’s powertrain differs from gasoline cars, many OBD-II fault categories are familiar. Temperature swings along the Wasatch Front can also trigger EVAP-related alerts. Our Murray team verifies whether the code points to a faulty part or a related condition like vacuum leaks, wiring faults, or sensor drift.

• EVAP leak checks start with the gas cap seal
• O2/MAF sensor data compared to Toyota specs
• Misfire diagnosis protects the catalytic converter

Yes if it’s steady and the car drives normally; no if it’s flashing—park safely to avoid catalytic converter damage.

A steady light typically means you can drive cautiously to a scheduled diagnostic. A flashing light indicates an active misfire that can overheat and damage the catalytic converter. In Murray traffic and I-15 speeds, continuing to drive with a flashing light can escalate repair costs.

• Steady = reduce load, avoid hard acceleration
• Flashing = stop driving; arrange towing if needed
• Schedule service for prompt diagnostics

Parts stores read generic OBD-II codes; dealer technicians use Toyota factory scan tools to diagnose root cause with proprietary data.

Code readers identify the system, not the failure. The same code can stem from multiple issues—sensor faults, wiring, leaks, or software updates. Our Toyota-certified equipment in Murray pulls freeze-frame data, bi-directional tests, and technical service bulletins to confirm what actually needs repair, then provides a written estimate.

• Factory scan access to Toyota-specific PIDs and tests
• Isolation testing before any parts are replaced
• Transparent findings with a documented estimate

No—resetting clears codes but also resets readiness monitors, and Utah inspections require monitors to be “Ready.”

After a battery disconnect or code clear, your Mirai must complete specific drive cycles before emissions systems report Ready. If the underlying fault remains, the monitor may not complete, or the light can return. Proper diagnosis in Murray ensures the actual issue is fixed so your vehicle passes legally.

• Readiness monitors must be set before testing
• Drive cycles vary by system and conditions
• Fix the root cause to avoid test failures

Larry H. Miller Toyota Murray at 5650 South State Street, Murray, UT 84107 provides factory-authorized Toyota diagnostics.

We serve the Salt Lake Valley and Greater Salt Lake City metro—Murray, Sandy, West Jordan, South Jordan, Millcreek, Holladay, and Taylorsville. Schedule online and our team will perform an OBD-II scan, review freeze-frame data, and complete pinpoint testing specific to the Mirai.

• Schedule an appointment online
• Check current service specials
• Written estimate before any repair is performed

Your visit starts with an initial OBD-II scan of the 2020 Toyota Mirai to capture stored and pending codes along with freeze-frame data. A technician reviews sensor values, fuel-trim trends, and mode-6 results to determine whether the code points to a component failure or a related issue such as wiring, vacuum leaks, or software calibration. We perform isolation testing as needed—smoke tests for EVAP leaks, circuit checks, or targeted functional tests—to confirm root cause. You receive a clear, written estimate before any repair is performed, so you can make an informed decision. Ready to move forward? Use our online portal to schedule service and we19ll coordinate a time that works for you.

LHM Toyota Murray serves the Salt Lake Valley and Greater Salt Lake City area—including Murray, Salt Lake City, Sandy, West Jordan, South Jordan, Millcreek, Holladay, and Taylorsville—with Toyota-specific diagnostic capability. Factory scan tools let us read proprietary data that generic readers can19t, which is vital on a hydrogen-fuel Mirai. Utah19s winter cold snaps and shoulder-season temperature swings can surface EVAP and cold-start related codes; we verify causes with data and pinpoint tests instead of guesswork. Opened in 1979, our dealership has decades of Toyota diagnostic expertise. Find us at 5650 South State Street, Murray, UT 84107; schedule online, or stop by for directions and check-in.

Common categories you may see on a 2020 Toyota Mirai include EVAP system leaks (often gas cap seal issues), oxygen sensor circuit or performance faults, mass air flow (MAF) sensor range/performance concerns, catalyst efficiency below threshold, and cylinder misfire codes. An EVAP leak left unresolved can keep readiness monitors from completing and cause repeated test failures. Ignoring misfire or catalyst-related codes risks overheating and damaging the catalytic converter, increasing repair costs substantially. Sensor faults may also mask underlying wiring or vacuum issues. Bring your 2020 Toyota Mirai to Larry H. Miller Toyota Murray in Murray for an accurate diagnosis — schedule service.