P0424: Heated Catalyst Temperature Below Threshold — Bank 1
What to do
Driveable, will fail an emissions test. The fault is usually electrical rather than the converter itself.
What this code means
The heated converter on bank 1 is not reaching the temperature the module expects. This is a temperature complaint rather than an efficiency one, which makes it more specific and easier to work with: either the heater is not producing heat, or the sensor reporting temperature is wrong.
Measuring current draw through the heater circuit separates the two directly. A heater drawing nothing has failed or lost its supply; a heater drawing normal current alongside a low temperature reading points at the sensor.
Likely causes
Start here
- Failed catalyst heater element · specialist
- Faulty catalyst temperature sensor · moderate
- Open heater supply circuit · moderate
Less common
- Corroded or loose connector · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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