auto zone says the air injection system fault, probable causes are aa1 circuit relay defective or fuse open, aa2 check connector and wiring, aa3 air pump defective or hoses blocked.The P0491 said The Secondary air injection aaflownbank 1, Explanation the ECM detected that there was insufficient mass aaair flow change while the Air pump switching test, Probable cause aa1 Secindary Air vacuum hoses off or leaking, aa2 Failed diverter valve system, aa3 Failed Air bypass solenoid, aa4 Secondary Air hoses off or damaged. Is this a expensive fix?
 
Answer Ranks
This week's top 10
| 1 globalhelper | 6 goodguy |
| 2 wetry | 7 ebans777 |
| 3 ziptie12 | 8 FREDDY BLUE |
| 4 wenyan | 9 Superior Auto Diesel Repair |
| 5 tunnelram | 10 team g performance |