<p>Bosch 077 133 471 KX is a new air mass sensor (also written 077133471KX) for the Audi S4 from 2004 to 2009 with the 4.2L V8 engine. The sensor measures the amount of air entering the engine and sends that signal to the engine control unit, which uses it to calculate the fuel needed for each combustion cycle.</p> <p>Cross reference numbers for this part are 0-280-218-08P and 028021808P. The sensor carries a 24-month warranty.</p> <p>Check the Compatible Vehicles table below to confirm fitment before you order.</p> <h3>Key Features</h3> <table style="width:100%;border-collapse:collapse;"><tbody> <tr> <td style="padding:6px 12px 6px 0;color:#6b6b6b;border-bottom:1px solid #e5e5e5;vertical-align:top;">Brand</td> <td style="padding:6px 0;border-bottom:1px solid #e5e5e5;">Bosch</td> </tr> <tr> <td style="padding:6px 12px 6px 0;color:#6b6b6b;border-bottom:1px solid #e5e5e5;vertical-align:top;">Part Number</td> <td style="padding:6px 0;border-bottom:1px solid #e5e5e5;">077 133 471 KX</td> </tr> <tr> <td style="padding:6px 12px 6px 0;color:#6b6b6b;border-bottom:1px solid #e5e5e5;vertical-align:top;">Part Type</td> <td style="padding:6px 0;border-bottom:1px solid #e5e5e5;">Air Mass Sensor</td> </tr> <tr> <td style="padding:6px 12px 6px 0;color:#6b6b6b;border-bottom:1px solid #e5e5e5;vertical-align:top;">Description</td> <td style="padding:6px 0;border-bottom:1px solid #e5e5e5;">Air Mass Sensor (New)</td> </tr> <tr> <td style="padding:6px 12px 6px 0;color:#6b6b6b;border-bottom:1px solid #e5e5e5;vertical-align:top;">Weight</td> <td style="padding:6px 0;border-bottom:1px solid #e5e5e5;">0.84 lbs</td> </tr> <tr> <td style="padding:6px 12px 6px 0;color:#6b6b6b;border-bottom:1px solid #e5e5e5;vertical-align:top;">Cross Reference Number</td> <td style="padding:6px 0;border-bottom:1px solid #e5e5e5;">0-280-218-08P, 028021808P</td> </tr> <tr> <td style="padding:6px 12px 6px 0;color:#6b6b6b;border-bottom:1px solid #e5e5e5;vertical-align:top;">Warranty</td> <td style="padding:6px 0;border-bottom:1px solid #e5e5e5;">24 Months</td> </tr> </tbody></table> <h3>Compatible Vehicles</h3> <div style="overflow-x:auto;"><table style="width:100%;border-collapse:collapse;font-size:0.95em;"> <thead><tr> <th style="text-align:left;padding:6px 8px 6px 0;border-bottom:2px solid #d0d0d0;">Year</th> <th style="text-align:left;padding:6px 8px 6px 0;border-bottom:2px solid #d0d0d0;">Make</th> <th style="text-align:left;padding:6px 8px 6px 0;border-bottom:2px solid #d0d0d0;">Model</th> <th style="text-align:left;padding:6px 8px 6px 0;border-bottom:2px solid #d0d0d0;">Engine</th> <th style="text-align:left;padding:6px 8px 6px 0;border-bottom:2px solid #d0d0d0;">Notes</th> </tr></thead> <tbody><tr> <td style="padding:5px 8px 5px 0;border-bottom:1px solid #eeeeee;vertical-align:top;">2004–2009</td> <td style="padding:5px 8px 5px 0;border-bottom:1px solid #eeeeee;vertical-align:top;">Audi</td> <td style="padding:5px 8px 5px 0;border-bottom:1px solid #eeeeee;vertical-align:top;">S4</td> <td style="padding:5px 8px 5px 0;border-bottom:1px solid #eeeeee;vertical-align:top;">4.2L V8 4163cc</td> <td style="padding:5px 8px 5px 0;border-bottom:1px solid #eeeeee;vertical-align:top;"></td> </tr></tbody> </table></div>