When your 2022 Lexus RX requires multiple start attempts before finally firing, something in the starting equation isn't consistently available on the first try. This frustrating symptom indicates a component working intermittently rather than completely failing.
Fuel System Prime Issues
The fuel system should build pressure when you turn the key to ON before cranking. If you hear the fuel pump prime and then immediately try starting, adequate pressure should be present. If starting works better after holding the key in ON position for a few extra seconds, fuel pressure may be bleeding down between starts, suggesting a leaking fuel injector or check valve.
Key Fob Detection Variability
The Smart Key system must detect your key fob before authorizing starting. Weak fob batteries or interference can cause inconsistent detection - sometimes it works on the first try, sometimes it takes several attempts. Try holding the fob directly against the start button to use the backup reader and see if reliability improves.
Starter Relay Intermittent Contact
Starter relays can develop internal contact wear that causes intermittent failure to pass current. The relay may click but not consistently complete the circuit. Since relays are inexpensive, consider replacing the starter relay as a diagnostic step when intermittent starting occurs.
Crankshaft Position Sensor
The crankshaft position sensor tells the engine computer when to fire the spark plugs and fuel injectors. An intermittently failing sensor can cause sporadic no-start conditions that eventually succeed after multiple attempts. These sensors can fail without setting a diagnostic code.
Battery and Connection Marginal Issues
A battery with borderline capacity or connections with microscopic corrosion can cause intermittent starting. The first attempt may not quite have enough power, but subsequent attempts with slight variations succeed. Have the battery load tested and clean all connections thoroughly.
Vapor Lock and Heat Soak
If multiple tries are needed specifically after hot restarts (stopping for a short errand), heat soak affecting the fuel system may be causing temporary vapor lock. Modern fuel injection is resistant to this, but high underhood temperatures can still cause intermittent hot restart issues.