Traditional gasoline car fault
Search fault code and browse forum case posts.
This page is designed for quick diagnosis on gasoline vehicles by combining code lookup with real discussion cases. Enter a fault code to filter related topics, then compare symptom context such as cold start behavior, acceleration load, fuel-trim deviation, ignition misfire pattern, and recent maintenance history. Many codes can be triggered by shared root causes, so use cross-checks from multiple posts before replacing sensors, coils, injectors, or catalytic components.
P0171 OBD2 Fault in 2006 Pontiac Montana SV6 (3.5L V6) - Causes and Diagnostics
My 2006 Pontiac Montana SV6 with a 3.5L V6 engine has recently started triggering the P0171 diagnostic trouble code — System Too Lean Bank 1. Notably, this occurred without any ...
2006 Pontiac Montana SV6 | P0171P0420 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 | P04202002 Toyota Avalon 3.0L V6: Persistent P1135 & P1155 OBD2 Codes - Sensor 1 Issue Diagnosis
I own a 2002 Toyota Avalon XLS with a 3.0L V6 engine. I recently encountered persistent OBD2 fault codes P1135 and P1155, which indicate issues with the oxygen sensor heater cir...
TOYOTA AVALON | P11352001 Grand Prix 3.1L EGR Valve Wiring Issue: P0404 Code Fix and Correct Wire Connections
Hello, The wiring harness for the EGR valve on my 2001 Grand Prix (3.1L non-turbo) has pulled out of its retention clip. I reinserted the wires as best as I could, but the vehi...
2001 Grand Prix | P04042007 Cadillac STS P0496 EVAP System Fault: Location, Causes, and Repair Guidance
My 2007 Cadillac STS has triggered a P0496 OBD-II diagnostic code, indicating an issue with the Evaporative Emission (EVAP) system. I'm trying to understand where the EVAP purge...
2007 Cadillac STS | P0496Toyota Sienna 2010 LE AWD - P0138 O2 Sensor Error After Under-Hood Detailing
Hi everyone, I own a 2010 Toyota Sienna LE AWD. Shortly after a recent under-the-hood detailing session — which included cleaning the engine bay and leaving residual moisture i...
Toyota Sienna 2010 LE AWD | P01382004 Pontiac Grand Prix GT P0303 Misfire: Diagnosis and Fixes for Cylinder 3
My 2004 Pontiac Grand Prix GT with a 3800 V6 engine is showing a P0303 diagnostic trouble code, indicating a misfire in cylinder #3. The symptoms include hesitation when releasi...
2004 Grand Prix GT | P03032001 Jeep Wrangler 4.0L A/T DTC P0300, P03-05, P0306: No Start to Misfire After Crank Sensor Replacement
I own a 2001 Jeep Wrangler with a 4.0L engine and 3-speed automatic transmission (stock, no modifications). The vehicle initially failed to start, which led me to replace the cr...
2001 jeep wrangler | P0300VW Touran No Power with P0234 Fault Code: Boost Pressure Regulation Limit Exceeded
My VW Touran is experiencing a complete loss of power. The vehicle displays fault code P0234: 'Boost Pressure Regulation - Limit Exceeded (Overboost Condition)'. This indicates ...
vw touran | P02341999 Jeep Wrangler 4.0L P0138 O2 Sensor Post-Cat High Voltage Code Diagnosis
I own a 1999 Jeep Wrangler with a 4.0L engine and 5-speed manual transmission. After replacing the exhaust manifold, the check engine light activated approximately 50 miles late...
1999 wrangler | P0138Mercedes GL320 CDI 2007 - P1101 Code Explanation and Diagnosis: Is It MAF or Ambient Air Temperature Sensor?
I'm looking for clarification on the meaning of fault code P1101 in a 2007 Mercedes-Benz GL320 CDI. Despite searching online, I can't find a clear explanation for this specific ...
Mercedes | P11012004 Chevrolet 2500 V8 Gas Truck with P0174 and P0307 Codes: Diagnosis and Solutions
Hello everyone, I'm trying to avoid unnecessary part replacements before investing in repairs. My vehicle is a 2004 Chevrolet 2500 V8 gasoline truck, currently showing diagnosti...
chev truck | P01742007 Chevrolet Aveo LS P2188 Code: System Too Rich at Idle - Diagnosis and Fixes
I recently purchased a 2007 Chevrolet Aveo LS and am experiencing an OBD-II diagnostic code P2188, which indicates 'System Too Rich at Idle - Bank 1'. The engine runs smoothly a...
Chevy Aveo | P21882006 Hyundai Elantra P0036, P0136, P0455: O2 Sensor and EVAP System Fault Diagnosis
I recently used my code reader for the first time and detected three diagnostic trouble codes (DTCs) on my 2006 Hyundai Elantra: - P0036: HO2S Heater Control Circuit High (Bank...
2006 Hyundai Elantra | P01362002 Nissan Altima P0335 Fault: Should You Replace the Crankshaft Position Sensor?
My 2002 Nissan Altima with a 2.5-liter engine is throwing out fault code P0335, but I'm not experiencing any hard starting or rough idling—only the check engine light is on. Sho...
Nissan Altima | P03352003 Yukon Denali XL P0101, P0135, P0161 Troubleshooting Guide: Can I Fix These Codes Myself?
Hi everyone, I'm looking for help diagnosing and fixing three OBD-II trouble codes on my wife's 2003 Yukon Denali XL: - P0101: Mass Air Flow (MAF) Circuit Range/Performance Pr...
03 Yukon Denali XL | P01012000 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 | P0171Practical workflow for fault-code troubleshooting
Start by confirming battery voltage and reading freeze-frame data, then inspect wiring and connectors before replacing parts. If the code returns after clearing, record the exact driving or idling condition when it reappears. Prefer case threads with complete repair feedback, because confirmed outcomes provide stronger guidance than one-time symptom descriptions. Following a step-by-step workflow reduces repeated repairs and lowers total diagnosis time.