P0420 on a Honda CR-V
P0420 means catalyst System Efficiency Below Threshold (Bank 1). On the CR-V, a few causes come up far more than others.
What P0420 usually means on a CR-V
P0420 on the CR-V means bank 1's catalytic converter is reading below its efficiency threshold. On K24 CR-Vs the original converter simply ages out past 150k. On the 1.5T, unresolved misfires or fuel-diluted oil can overheat and prematurely degrade the cat. A slow rear O2 sensor is a frequent false alarm worth eliminating first.
Most common causes on the CR-V
- Aged converter
Factory cats on high-mileage K24 CR-Vs lose efficiency with age.
- Lazy downstream O2 sensor
A sluggish rear sensor imitates a dead cat at a fraction of the cost.
- Misfire or dilution overheating the cat (1.5T)
Untreated misfires or fuel-thinned oil on the L15B cook the converter.
- Exhaust leak upstream of the rear sensor
A leak skews the efficiency reading feeding the monitor.
What P0420 costs to fix on a CR-V
A direct-fit converter for the CR-V runs several hundred dollars with reasonable underbody access. Confirm the rear O2 sensor with live data before spending on a cat. On the 1.5T, fix the underlying misfire or dilution first or the new converter will suffer too.
Year, engine and mileage change the answer. Start a case and Redline weighs these causes against what your car shows, then names the check that would settle it.
Other codes on the Honda CR-V
Related symptoms
Honda CR-V problems & recalls by year
Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0420 behavior is covered on the main P0420 page. Confirm with a scan tool before buying parts.
P0420 on your CR-V?
Every problem becomes a Case. Tell Redline what your CR-V is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.