4-56 FI SYSTEM DIAGNOSIS “C22” (P1450-H/L) AP SENSOR CIRCUIT MALFUNCTION DETECTED CONDITION POSSIBLE CAUSE C22 AP sensor voltage is not within the fol- • Clogged air passage with dust lowing range. • AP sensor circuit open or shorted to ground 0.5 V Sensor voltage < 4.85 V • AP sensor malfunction NOTE: • ECM malfunction Note that atmospheric pressure varies depending on weather conditions as well as altitude. Take that into consideration when inspecting voltage. P1450 H Sensor voltage is higher than specified • AP sensor circuit shorted to VCC or ground circuit value. open L Sensor voltage is lower than specified • AP sensor circuit open or shorted to ground or value. VCC circuit open AP sensor ECM R VCC E G/Y PL AP B/Br E2 AM INSPECTION S 1 Step 1 (When indicating C22:) 1) Turn the ignition switch OFF. 2) Remove the front seat. (8-7) 3) Check the AP sensor coupler for loose or poor contacts. If OK, then measure the AP sensor input voltage.