FI SYSTEM DIAGNOSIS 4-61 “C23” (P1651-H/L) TO SENSOR CIRCUIT MALFUNCTION DETECTED CONDITION POSSIBLE CAUSE C23 The sensor voltage should be the follow- • TO sensor circuit open or short ing for 2 sec. and more, after ignition • TO sensor malfunction switch is turned ON. • ECM malfunction 0.2 V Sensor voltage < 4.8 V P1651 H Sensor voltage is higher than specified • TO sensor circuit shorted to VCC or ground circuit value. open L Sensor voltage is lower than specified • TO sensor circuit open or shorted to ground or value. VCC circuit open TO sensor ECM R VCC B TOS B/Br E E2 PL INSPECTION 1 Step 1 (When indicating C23:) M 1) Turn the ignition switch OFF. 2) Lift and support the fuel tank. (5-3) A 3) Check the TO sensor coupler for loose or poor contacts. S If OK, then measure the TO sensor resistance. 4) Disconnect the TO sensor coupler. 5) Measure the resistance between terminal A and terminal C. 1 TO sensor resistance: 16.5 – 22.3 kΩ (Terminal A – Terminal C) 09900-25008: Multi-circuit tester set Tester knob indication: Resistance (Ω) Is the resistance OK? YES Go to Step 2. NO Replace the TO sensor with a new one.