P04xx OBD2 codes — causes & fixes

All P04xx diagnostic trouble codes (171 published): short meanings and links to full articles. Canonical URLs /dtc/P04XX/.

• P0400
• P0401
• P0402
• P0403
• P0404
• P0405
• P0406
• P0407
• P0408
• P0409
• P040A
• P040B
• P040C
• P040D
• P040E
• P040F
• P0410
• P0411
• P0412
• P0413
• P0414
• P0415
• P0416
• P0417
• P0418
• P0419
• P041A
• P041B
• P041C
• P041D
• P041E
• P041F
• P0420
• P0421
• P0422
• P0423
• P0424
• P0425
• P0426
• P0427
• P0428
• P0429
• P042A
• P042B
• P042C
• P042D
• P042E
• P042F