When the Start Button Does Nothing
Push-to-start systems have replaced the traditional ignition key on most new vehicles sold in New Zealand. They're generally reliable, but when they fail, the diagnostic path is less intuitive than a traditional keyed ignition.
If pressing the start button produces no response at all, or the car shows a "key not detected" warning, work through these possibilities in order.
Step 1: Key Fob Battery
A flat fob battery is the most common cause. Try holding the fob directly against the start button while pressing. If the car starts, replace the fob battery (CR2032, $3–$8 NZD).
Step 2: The Car's 12V Battery
The start button and keyless system run on the vehicle's main 12V battery. A flat or failed main battery means the entire system has no power. Symptoms: nothing happens when you press the button, or dash lights are dim/absent. Jump-starting (or jump-pack) will confirm this.
Step 3: Brake Pedal Not Depressed
Most push-to-start systems require the brake pedal to be fully depressed before the start button will work. This is a safety interlock — the system won't engage starter unless it confirms the driver has a foot on the brake. A faulty brake pedal position switch (also called the brake light switch) can prevent this signal from being sent.
Check: press the brake pedal firmly. If the brake lights at the rear aren't working (visible in a reflection), the brake switch may be the fault.
Step 4: Key Antenna or BCM Fault
The body control module (BCM) manages the keyless entry and start system. A BCM fault can prevent key detection even with a healthy fob. Fault codes stored in the BCM will usually point to this — requires a scan tool.
The antenna that reads the fob's signal (often in the door handles and the centre console) can corrode or develop a wiring fault, preventing fob detection in certain positions inside the car.
Step 5: Clutch Interlock (Manual Gearbox)
If your vehicle has a manual gearbox and push-to-start, it will require the clutch pedal to be depressed (not the brake) to crank. A faulty clutch position switch will prevent this — the system won't know the clutch is in.
Costs
- Brake pedal switch: $40–$120 NZD fitted
- BCM programming or replacement: $300–$900 NZD (dealer or specialist with OEM software)
- Key fob antenna repair: $80–$250 NZD
- New key fob programming: $150–$400 NZD
When to Go to the Dealer
Complex keyless start and BCM issues sometimes require manufacturer-specific diagnostic software only available at a dealer or authorised workshop. If the car shows a persistent "key not found" or "start system fault" message after checking the basics, this is the appropriate escalation.