Traditional gasoline car fault

2001 Chevrolet Impala 3.8L P0420 Fault: Converter Below Threshold Despite CAT Ready Status

Hi, I'm experiencing a check engine light on my 2001 Chevrolet Impala with the 3.8L engine, showing a DTC P0420 indicating 'Catalyst System Efficiency Below Threshold'. The vehi...

2001 chevy impala | P0420

1996 Mercury Cougar P0420 P0430 P1443 Emissions Failure - How to Fix Without Replacing Catalytic Converters?

My 1996 Mercury Cougar is failing emissions inspection due to fault codes P1443, P0420, and P0430. The emissions tester claims the catalytic converters are clogged, but replacin...

1996 Mercury Cougar | P0420

P0420 Code Reappears on 1998 Pontiac G/A 3.1L V6 After Cat and O2 Sensor Replacement

I'm experiencing a recurring P0420 diagnostic trouble code (DTC) on my 1998 Pontiac G/A with a 3.1L V6 engine. I recently replaced the catalytic converter with a direct-fit Walk...

Pontiac 3.1 V6 | P0420

P0420 Fault on 2002 Chevrolet Malibu - Catalyst System Efficiency Below Threshold

I received a P0420 diagnostic trouble code back in September 2012, and had the catalytic converter and downstream oxygen sensor replaced at a repair shop. Recently, the check en...

Malibu | P0420

2000 GMC Silverado 5.3L P0171 P0174 P0420 Fault: Diagnosis & Solutions After Intake Gasket Replacement

My 2000 GMC Silverado with a 5.3L V8 engine is currently showing persistent OBD-II fault codes: P0171 (System Too Lean Bank 1), P0174 (System Too Lean Bank 2), and P0420 (Cataly...

2000 Silverado | P0171

Mazda 6 2002 | P0420 and P2185 Error Codes: Causes and Diagnosis Steps

I own a 2002 Mazda 6 with a 2.3L engine. The check engine light is on, and I've received two diagnostic error codes: P0420 (Catalyst System Efficiency Below Threshold - Bank 1) ...

Mazda 6 | P0420

Frequent P0420 Catalyst Efficiency Code on 2008 GMC Acadia - Diagnosis and Fixes

We own a 2008 GMC Acadia with approximately 80,000 miles and have been experiencing recurring P0420 fault codes. The issue appears to occur only briefly—long enough for the engi...

2008 Acadia | P0420

2003 Saturn L200 P0420 Error After Resolving P0300 and P0141/P0172 - O2 Sensor or Catalytic Converter Issue?

My 2003 Saturn L200 (2.2L 4-cylinder, 130,000 miles) has developed a P0420 error two days after successfully resolving previous issues of P0300 and P0141/P0172. I replaced seve...

2003 Saturn L200 | P0141

P0420 Code in Jetta: Is a Stuck Thermostat Causing the Issue?

I'm experiencing a P0420 diagnostic trouble code on my Jetta. Additionally, I've noticed the vehicle is not warming up properly, especially under low load conditions—where the e...

Jetta | P0420

P0420/P0430 Fault Diagnosis and Emissions Testing Solution for 2005 Lexus GX 470 V8

This is my first post on the forum, and I'm grateful for the community's support. I've been using an Actron CP9180 scanner to capture detailed diagnostic data, including Diagnos...

Lexus V-8 | P0420

1997 Ford Probe GT OBD2 Codes P0300, P0304, P0420, P1170, P1173 - Misfire, Catalyst Efficiency, O2 Sensor Issues

I own a 1997 Ford Probe GT with a 2.5L V6 engine and 5-speed manual transmission. The 'Check Engine' light turned on yesterday and began flashing, indicating a serious issue. Af...

97 Ford Probe GT | P0304

P0420 Fault Code on 2000 Camry V6 LXE - Possible Bad Converter or Rear O2 Sensor?

About three weeks ago, I had the exhaust pipe with catalytic converter replaced on my 2000 Toyota Camry V6 LXE. The original pipe was severely rusted at one of the mesh elbows. ...

2000 Camry | P0420

P0420 and P0430 Codes on 2002 Toyota RAV4: How to Fix for Smog Check at Low Cost

I'm trying to pass a California smog check on my 2002 Toyota RAV4, but the check engine light is on due to both P0420 and P0430 diagnostic codes. While the vehicle passes emissi...

2002 Rav4 | P0420

2000 Honda Civic P0420 Code After Aftermarket Distributor/Coil Replacement - Solutions & Diagnostics

I own a 2000 Honda Civic that recently triggered a P042-0 diagnostic trouble code (DTC) after replacing the distributor and coil assembly. The vehicle experienced a sudden loss ...

2000 Honda Civic | P0420

2001 Toyota Corolla P0420 Fault at 125k Miles - Best Catalytic Converter Brands & Fitment Guide

I'm planning to replace the catalytic converter on my 2001 Toyota Corolla with 125,000 miles and am looking for member experiences with popular brands. Specifically, I'm conside...

2001 Corolla | P0420

2005 Nissan Murano 3.5L DOHC: PO110 and P0420 Codes, Rough Idle, Power Loss and Backfiring After Fix - Diagnosis and Solution

I have a 2005 Nissan Murano with a 3.5L DOHC engine that came in with diagnostic codes PO110 and P0420, along with a noticeable rough idle. While driving, I observed intermitten...

2005 Nissan Murano 3.5 Dohc | P0420

Suzuki Forenza 2005 OBD2 Codes P0420, P0703, and P02BF - Troubleshooting Guide

I'm looking for help diagnosing three OBD2 trouble codes on my 2005 Suzuki Forenza: P0420, P0703, and P02BF. The vehicle has a 1.8L engine with an automatic transmission. The o...

Suzuki Forenza | P0420

2000 Nissan Maxima P0420 Fault: Diagnosis and Repair Guide

I have a 2000 Nissan Maxima displaying fault code P0420. I'm looking for guidance on how to diagnose and resolve this issue effectively. The P0420 code indicates a catalytic con...

2000 Maxima | P0420

2000 Toyota Tundra PO120, PO121, and PO420 Codes - Loss of Throttle Response After Restart

My wife's 2000 Toyota Tundra with a 4.7L V8 engine and 180,000 miles is experiencing complete loss of throttle response except when flooring the gas (WOT). After shutting down t...

2000 Toyota Tundra | P0420