FI SYSTEM DIAGNOSIS 4-57 4) Disconnect the AP sensor coupler. 1 5) Turn the ignition switch ON. 6) Measure the voltage at the Red wire and ground. V 7) If OK, then measure the voltage at the Red wire A and B/Br wire B. AP sensor input voltage: 4.5 – 5.5 V (+ Red – - Ground) (+ Red – - B/Br) 09900-25008: Multi-circuit tester set Tester knob indication: Voltage () Is the voltage OK? YES Go to Step 2. • Loose or poor contacts on the ECM coupler NO (terminal A or S) • Open or short circuit in the Red wire or B/Br wire Step 1 (When indicating P1450-H:) 1 1) Turn the ignition switch OFF. E 2) Remove the front seat. (8-7) 3) Check the AP sensor coupler for loose or poor contacts. L If OK, then check the AP sensor lead wire continuity. P AM 4) Disconnect the AP sensor coupler. 1 S 5) Check the continuity between Red wire A and G/Y wire C. If the sound is not heard from the tester, the circuit condition is OK.