← View Generic P0429 Guide Severity: Medium
🚗 Vehicle-Specific Guide

This guide is customized for your 2021 Honda PASSPORT

P0429: P0429: Catalyst Efficiency Below Threshold

on 2021 Honda PASSPORT

Fix Cost
$200 - $1000
Parts & Labor
Difficulty
3/5
1-2 hours
DIY Possible?
❌ No
Pro recommended
Your Vehicle
2021 Honda
PASSPORT
⚠️

Important for 2021 Honda PASSPORT Owners

Before starting repairs, verify which engine your 2021 Honda PASSPORT has. Check your VIN or engine code to ensure you order the correct parts.

📖 What Does P0429 Mean on 2021 Honda PASSPORT?

The onboard computer has detected that the catalytic converter is not functioning within normal parameters, which can lead to increased emissions and decreased fuel efficiency.
⚠️

Symptoms

  • • Rough idling
  • • decreased fuel efficiency
  • • increased emissions
  • • check engine light illuminated
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Common Causes

  • • Clogged or dirty catalytic converter
  • • faulty oxygen sensor
  • • faulty fuel injector
  • • faulty ignition coil
🛠️

How to Fix P0429 on 2021 Honda PASSPORT

1. Inspect and clean the catalytic converter, 2. Replace the oxygen sensor, 3. Replace the fuel injector, 4. Replace the ignition coil

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Need Maintenance Info for Your PASSPORT?

Get oil capacity, filter specs, and torque settings for your specific 2021 Honda PASSPORT.

View 2021 Honda PASSPORT Specs

Parts for 2021 Honda PASSPORT

catalytic converter Shop ↗ oxygen sensor Shop ↗ fuel injector Shop ↗ ignition coil Shop ↗

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OBD2 Scanner

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Related Diagnostic Codes

Other codes that may appear with P0429

P0427 Sequential Code

P0427: Catalytic Converter Efficiency Below Threshold

Medium
P0428 Sequential Code

P0428: Catalytic Converter Efficiency Below Threshold

Medium
P0430 Sequential Code

Catalyst System Efficiency Below Threshold Bank 2

Medium
P0431 Sequential Code

P0431: Exhaust Gas Recirculation (EGR) System Malfunction

Medium

💡 Why These Codes Are Related:

  • • Similar Issues: Same root cause or component failure
  • • Related Problems: Often occur together due to system interactions
  • • Sequential Codes: Progressive failure stages or multiple sensors
  • • Same System: Components within the same automotive system