Why wont my Toyota Yaris Hybrid start?

In most cases, a Yaris Hybrid won’t start because the 12-volt auxiliary battery is depleted, the key fob isn’t being detected, or the vehicle isn’t in the Ready mode. Recharging or replacing the 12V battery, replacing the key fob battery, or ensuring you follow the correct start procedure can restore starting capability.

The Toyota Yaris Hybrid relies on a combined petrol-electric powertrain that only awakens when the 12V electrical system is healthy and the car recognizes the key. If the 12V battery is weak or a security feature blocks recognition, you may see little to no response when pressing the start button. The guidance below covers the most common causes and practical steps to diagnose them before seeking professional help.

Common causes at a glance

These are the most frequent reasons a Yaris Hybrid refuses to start, along with quick checks you can perform yourself.

• Dead or weak 12-volt auxiliary battery



• Car not in Park (P) or brake pedal not pressed firmly when starting


• Immobilizer or security system fault


• Corroded or loose battery connections or blown fuses in the 12V circuit


• High-voltage system fault or inverter warning


• Electrical gremlins such as faulty relays or ECU faults


• Extreme temperatures affecting battery performance

If none of these conditions are present, the issue may require diagnostic tools and service from a Toyota technician.

Step-by-step troubleshooting

Follow these steps in order to identify the root cause and decide whether you can fix it yourself or need roadside assistance or a mechanic.

1. Check the 12-volt battery voltage with a multimeter. A healthy battery typically reads around 12.6 volts; readings below about 12.0 volts suggest a discharged or failing battery that needs charging or replacement.


2. Inspect the battery terminals for corrosion, cracks, or loose connections. Clean any corrosion and firmly re-tighten clamps if needed.


3. Test the key fob: replace the fob battery if you have a spare, and try unlocking and starting with the fob inside the vehicle. If the fob is not detected, try using the mechanical key method if your model provides it.


4. Ensure the car is in Park (P) with the parking brake engaged, then press the brake pedal firmly and press the Power button. If there is no response, try holding the Power button while pressing the brake pedal for several seconds.


5. Look for warning lights on the dash (for example, Check Hybrid System, battery, or inverter). If any warning appears, note the message and consult the manual or a professional.


6. If the 12V battery is dead and you intend to jump-start, follow proper jump-start procedures or contact roadside assistance. Do not attempt to jump the high-voltage system; use only the 12V jump connections described in your owner's manual and ensure safety precautions are observed.


7. If you still can’t start after these checks, arrange a diagnostic with a Toyota dealer or qualified technician. Persistent no-start conditions could indicate a HV battery, inverter, or ECU fault that requires specialized equipment.

These steps are designed to help you safely determine whether the problem is minor or requires professional diagnostics. If you notice any signs of damage, burning smells, or unusual sounds, stop and seek help immediately.

Safety note on high-voltage systems

Hybrid vehicles contain high-voltage components. Do not attempt to service the inverter, traction battery, or high-voltage wiring yourself. If you’re unsure, contact roadside assistance or a qualified technician. Keep clear of high-voltage components and avoid water exposure around the battery compartment.

Following these precautions helps prevent injury and avoids accidental damage to the vehicle’s electrical system.

When to seek professional help

Call a mechanic or roadside assistance if the car shows any of the following or if the no-start persists after the basic checks:

• Persistent 12V battery failure or repeated discharge after charging


• Warning lights related to the hybrid system or inverter


• Visible damage to wiring or connectors, or a burning smell


• Inability to obtain a diagnostic code or readouts from the vehicle’s onboard computer

Professional diagnostics can determine whether the issue lies with the 12V system, immobilizer, high-voltage components, or a more complex control-system fault.

Preventive tips to avoid future no-start issues

Regular maintenance and a few proactive habits can reduce the likelihood of a no-start situation:

• Keep the 12-volt battery in good health with regular checks and replacement every few years as advised by Toyota.


• Replace the key fob battery as needed and ensure the fob remains within range of the vehicle’s receiver.


• Avoid leaving lights or electrical accessories on when the car is off to protect the 12V battery.


• During extreme temperatures, consider charging or monitoring the 12V battery more frequently.


• Follow recommended service intervals for the hybrid system and electrical components.

Staying ahead on maintenance can keep the vehicle’s starting system reliable and reduce the chance of unexpected no-starts.

Summary

Most Toyota Yaris Hybrid start issues trace back to the 12-volt auxiliary battery, key fob recognition, or improper start procedure. By checking the 12V battery and connections, ensuring the key is detected, and confirming the vehicle is in Park with the brake pressed, many no-start problems are resolvable without a tow. If problems persist, professional diagnostics are recommended to inspect the high-voltage system, immobilizer, and control modules. Regular maintenance and awareness of temperature effects can help prevent future no-start scenarios.

What causes a Toyota Yaris not to start?

A Toyota Yaris may not start due to a weak battery, starter issues, or fuel system problems. Common fixes include jump-starting, checking for and cleaning corroded battery terminals, and verifying there is enough fuel. If the problem persists, it could be a faulty starter, fuel pump, or a problem with the ignition or safety switches.
 
This video explains how to troubleshoot starting problems in a Toyota Yaris: 58sCar Knights LTDYouTube · Jan 26, 2025
Common causes and solutions

• Dead or weak battery: This is the most frequent cause. You may hear a clicking noise or see dimming lights when trying to start. 
  • Solution: Jump-start the car or replace the battery. Check the battery terminals for corrosion and clean them if necessary. 
• Starter motor issues: If the car has power (lights and radio work) but won't crank, or makes a grinding noise, the starter may be failing. 
  • Solution: A bad starter can be diagnosed and replaced, but first, rule out the battery as the cause. 
• Fuel system problems: An empty tank, clogged fuel filter, or a failing fuel pump can prevent starting. 
  • Solution: Make sure you have enough gas. If the issue is the filter or pump, it will require a mechanic's diagnosis. 
• Safety/ignition switch issues: Some Yaris models have issues with the brake pedal switch or a neutral safety switch that prevents starting if the car is not in park or neutral. 
  • Solution: Make sure the car is fully in "Park" or "Neutral." You can also try pushing the clutch pedal or wiggling the steering wheel to see if a safety switch is the issue. 

You can watch this video to see how to check and clean a Toyota Yaris battery: 58sProject Fix-ItYouTube · Sep 13, 2024
Other potential issues

• Immobilizer system: The car's security system may be preventing the start if it doesn't recognize the key. 
  • Solution: Try a spare key. A weak key fob battery can also cause issues. 
• Blown fuse or relay: A blown fuse or faulty relay in the starting or fuel system could be the problem. 
  • Solution: Check the fuse box for any blown fuses. A faulty starter relay can also be an issue. 

Why is my hybrid engine not starting?

A hybrid car may not start due to a dead 12-volt battery, a problem with the fuel system, issues with the high-voltage battery, or a faulty starter motor. To troubleshoot, first check if the 12-volt battery is dead by seeing if lights turn on and trying a jump-start (following safety precautions), then consider potential fuel delivery problems or a failing starter. If those don't work, it may be a high-voltage battery issue, which often requires professional diagnosis and repair.
 
Common causes and solutions 
This video explains common reasons why a hybrid or electric car might not start: 1mHybrid Solution DiagnosticsYouTube · Aug 19, 2024
1. Dead or weak 12-volt battery 

• Why it happens: This is the most common culprit, even though the high-voltage battery powers the car. The smaller 12-volt battery is still needed to "wake up" the car's electronics and start the engine. 
• How to check/fix:
  • If the car has no power at all, the 12-volt battery is likely the problem. 
  • Try to jump-start the car using jumper cables, but be sure to follow the correct procedure for a hybrid, which may involve connecting to specific jump terminals instead of the battery terminals directly under the hood (check your owner's manual for location). 
  • You should only jump-start the 12-volt battery and never the high-voltage battery. 

2. Fuel system problems

• Why it happens: The gasoline engine needs fuel to start. A clogged fuel filter or a failing fuel pump can prevent enough fuel from reaching the engine, preventing it from starting. 
• How to check/fix:
  • This is a more advanced issue. If your car has been showing signs of fuel delivery problems like sputtering, a mechanic should check the fuel filter and fuel pump. 
  • These parts will need professional diagnosis and replacement if they are faulty. 

3. Faulty starter motor 

• Why it happens: Similar to a conventional car, a bad starter motor can prevent the gasoline engine from turning over. 
• How to check/fix:
  • If the car's lights and electronics work, but you hear a grinding noise or nothing happens when you try to start it, the starter motor or starter solenoid could be the problem. 
  • This issue requires professional diagnosis and repair. 

4. High-voltage battery issues

• Why it happens: The high-voltage battery is crucial for a hybrid's operation. While it's not the cause of a no-start very often, a severe failure can prevent the car from starting. 
• How to check/fix:
  • Diagnosis for a high-voltage battery issue is complex and requires specialized tools and knowledge. 
  • If a 12-volt jump-start and other basic checks don't work, a professional hybrid mechanic should be consulted to check the high-voltage system. 

If you need professional help

• If you've tried jump-starting and the problem persists, it's best to have the car towed to a mechanic, especially one experienced with hybrid vehicles.
• Some starting problems can be caused by issues with the car's computer system (ECU) or other electronic components that are beyond basic troubleshooting. 

What does it mean when my car has power but won't start?

A car with power but no start is likely caused by a faulty starter motor, a bad ignition switch, or a problem with the car's electrical connections. Other common culprits include a blown fuse or relay, a loose or corroded battery cable, a problem with the fuel pump, or a malfunctioning shift safety switch. 
Electrical and connection issues

• Faulty starter motor: If you hear a single click when you turn the key but the engine doesn't crank, a bad starter is a likely cause. 
• Bad ignition switch: This switch sends power to the starter. If it's faulty, accessories might work, but the engine won't crank. 
• Loose or corroded battery terminals: Even with a charged battery, corrosion or loose connections can prevent the flow of power needed to start the engine. 
• Blown fuse or faulty relay: A blown fuse or bad relay in the starter circuit can prevent power from reaching the starter. 
• Key fob battery (for push-button start): A dead or weak key fob battery can prevent a modern car from recognizing the key and starting. 

This video explains how to check for common causes like a faulty starter or a bad key fob battery: 55sFixITYouTube · Jan 23, 2025
Mechanical and safety issues

• Faulty neutral safety switch: In an automatic car, this switch prevents starting unless the gear selector is in Park or Neutral. Wiggling the shifter while trying to start can sometimes temporarily fix this. 
• Fuel system problems: If the engine cranks but won't "catch," a problem with the fuel pump or a clogged fuel filter could be the issue. 
• Security system lockout: The car's anti-theft system can malfunction and prevent it from starting. 
• Bad ignition coil or spark plugs: These are necessary for the engine to ignite. If they are faulty, the engine will crank but not start. 

This video demonstrates how to check the neutral safety switch and other potential issues: 59sHonest Mechanic ColoradoYouTube · Jan 24, 2024
Troubleshooting steps

• Check battery connections: Wiggle the battery terminals to ensure they are tight and clean off any white, powdery corrosion. 
• Try a jump-start: A jump-start can help determine if the battery has enough power to crank the engine, even if it shows a good voltage reading. 
• Check fuses and relays: Locate the fuse box and visually inspect the fuses for the starter and ignition. You can also swap a suspect relay with a known-good one, like the horn relay, to test it. 
• Check the gear selector: For automatic transmissions, try shifting to Neutral or jiggling the gear shifter while in Park to see if the safety switch is the culprit. 
• Replace the key fob battery: If you have a push-button start, try replacing the battery in your key fob. 

Why won't my Toyota hybrid car start?

A Toyota hybrid that won't start is most commonly caused by a weak or dead 12v battery or a low key fob battery. Other potential issues include a disconnected hybrid system component, a clogged fuel filter, a blown fuse, or an empty fuel tank. You should first check the key fob battery and try the backup starting method, as this is the simplest solution. If that doesn't work, the 12v battery is the next most likely cause.
 
This video explains common reasons why a Toyota hybrid car won't start, including a key fob issue: 55sToyota WorldYouTube · Oct 7, 2025
Initial checks to perform

• Check the key fob: A weak or dead fob battery is a common culprit. Try holding the fob directly against the start button to activate the backup start function. If this works, replace the fob battery. 
• Check the brake pedal: Ensure you are pressing the brake pedal down firmly when trying to start the car. The vehicle will not start if it doesn't detect your foot on the pedal. 
• Check for interference: Make sure there are no other electronic devices or metal objects interfering with the key fob's signal. Try moving your wallet or other items away from the fob. 

If the above doesn't work, investigate the 12v battery 
This video shows how to check the 12-volt battery in a Toyota Prius: 57shoohoohoblinYouTube · Mar 18, 2022

• Test the 12v battery: The auxiliary 12v battery is often the cause of starting issues. 
  • It's typically located in the rear passenger-side of the vehicle (trunk area). 
  • Use a voltmeter to check its voltage; it should be between 12.012.012.0 and 12.512.512.5 volts if the car has been off for a few hours. 
  • The battery may need to be replaced if it's old (often lasting 3-5 years). 
• Jump-start the car: If the 12v battery is the problem, you can jump-start the car. 
  • Locate the positive jump-start terminal under the fuse box under the hood. 
  • Connect the positive cable to this terminal. 
  • Connect the negative cable to a clean, unpainted metal surface on your car's chassis. 
  • Follow the full jump-starting procedure outlined in the resources. 

Other potential causes
This video explains how to reset a Toyota Hybrid System Malfunction: 58sAdvanced Level DiagnosticsYouTube · Sep 23, 2024

• Check fuses: Inspect fuses, particularly the AM2 fuse, as a blown fuse can prevent the car from starting. 
• Fuel issues: Ensure you have enough gas in the tank. A clogged fuel filter can also cause a no-start condition. 
• Hybrid system issues: A "Not Ready to Drive" warning often points to a hybrid system problem. This could be due to issues with the hybrid battery, inverter coolant pump, or other components, which may require a diagnostic scan. 

If the problem persists
If the issue continues after trying these steps, it's best to have the vehicle inspected by a qualified mechanic who can perform a full diagnostic scan to identify any complex hybrid system faults.