Chery P0420 Fix Cost Australia (2026)
Quick Answer:
80% of P0420 cases on Chery Tiggo 4/7/8 are caused by a faulty O2 sensor, not the catalytic converter. O2 sensor replacement costs $150-$300 AUD, while catalytic converter replacement costs $1,200-$2,500 AUD. Always diagnose the O2 sensor first.
Step-by-Step Diagnosis
- 1
Confirm the Code
Use an OBD2 scanner to read the exact code. P0420 means "Catalyst System Efficiency Below Threshold (Bank 1)". Clear the code and drive for 50km - if it returns, proceed to step 2.
- 2
Check for Exhaust Leaks
Inspect the exhaust system for leaks, especially near the catalytic converter. A leaking exhaust can trigger P0420. Fix any leaks first - cost: $50-$150 AUD.
- 3
Test O2 Sensors
The upstream and downstream O2 sensors should show different voltage patterns. If both sensors show similar readings, the catalytic converter may be faulty. If upstream sensor is erratic, replace it first.
- 4
Replace Faulty Component
O2 sensor: $150-$300 AUD (parts + labour, 1-2 hours). Catalytic converter: $1,200-$2,500 AUD (parts + labour, 3-5 hours). Always use OEM or high-quality aftermarket parts.
- 5
Clear Code and Test
Use OBD2 scanner to clear the code. Drive for 100km to confirm the code doesn't return. If it returns, the catalytic converter may need replacement.
Cost Comparison Australia
| Repair Option | Parts Cost | Labour | Total AUD |
|---|---|---|---|
| O2 Sensor (Aftermarket) | $80-$150 | $70-$150 | $150-$300 |
| O2 Sensor (OEM) | $150-$250 | $70-$150 | $220-$400 |
| Catalytic Converter (Aftermarket) | $600-$1,200 | $400-$800 | $1,000-$2,000 |
| Catalytic Converter (OEM) | $1,000-$1,800 | $500-$900 | $1,500-$2,700 |
*Prices based on Australian market data (2026). Labour rates: Dealer $220/hr, Independent $120-$150/hr.
DIY vs Dealer vs Independent
DIY
- ✓ Save $200-$400 labour
- ✓ 2-3 hours for first-timers
- ✗ Need OBD2 scanner ($50-$100)
- ✗ Moderate difficulty
Independent Mechanic
- ✓ $120-$150/hour labour
- ✓ Same day service
- ✓ Can source aftermarket parts
- ✗ May not honor Chery warranty
Chery Dealer
- ✓ $220/hour labour
- ✓ OEM parts guaranteed
- ✓ Warranty work covered
- ✗ Most expensive option
Frequently Asked Questions
What does P0420 mean on Chery vehicles?
P0420 means "Catalyst System Efficiency Below Threshold (Bank 1)". The engine computer detects the catalytic converter isn't working as efficiently as expected. On Chery Tiggo 4/7/8, 80% of cases are caused by a faulty O2 sensor, not the catalytic converter itself.
How much does P0420 repair cost in Australia?
O2 sensor replacement: $150-$300 AUD (parts + labour). Catalytic converter replacement: $1,200-$2,500 AUD. Always diagnose the O2 sensor first - it's the most common cause and much cheaper to fix.
Can I drive my Chery with P0420 code?
Yes, for short distances. P0420 won't cause immediate breakdown, but prolonged driving with a faulty catalytic converter can damage the engine. Get it diagnosed within 1-2 weeks. If the check engine light is flashing, stop driving immediately.
How do I fix P0420 on Chery Tiggo 4?
Step 1: Use OBD2 scanner to confirm P0420 code. Step 2: Check for exhaust leaks (common cause). Step 3: Test upstream and downstream O2 sensors. Step 4: Replace faulty O2 sensor ($150-$300 AUD). Step 5: Clear code and test drive. If code returns, catalytic converter may need replacement.
Where can I get P0420 fixed in Australia?
Options: (1) Chery dealer - warranty covered if under 7 years, $220/hour labour. (2) Independent mechanic - $120-$150/hour, can source aftermarket O2 sensors. (3) DIY - O2 sensor replacement is moderate difficulty, saves $200-$400 in labour.
Is P0420 covered under Chery warranty?
Chery Australia offers 7-year warranty. P0420 caused by manufacturing defects is covered. However, if caused by worn O2 sensor (normal wear item), it may not be covered after 3 years/100,000km. Check your warranty booklet or contact Chery Australia.
How long does P0420 repair take?
O2 sensor replacement: 1-2 hours at dealer, same day service. Catalytic converter replacement: 3-5 hours, may require overnight stay. DIY O2 sensor replacement: 2-3 hours for first-timers, 1 hour for experienced mechanics.