Posts Tagged: P0171

Top Causes of the P0171 Code and P0174 Code

Fix a P0171 and P0174 Lean Code Using Proven Diagnostic Strategy Quick Summary The P0171 and P0174 codes are some of the most misunderstood OBD-II trouble codes. Both codes indicate the engine is running too lean—either too much air or too little fuel. A P0171 indicates a lean condition on bank 1, while a P0174 indicates a lean condition on bank 2. Most of the time, these codes are caused by something simple, such as a vacuum leak, a dirty MAF sensor, or low fuel pressure. But I’ve also seen … Read More