Code 26: Air Temperature Sensor

NOTE: Refer to illustration for ECU connector and terminal identification. See Figure .

Turn ignition on. Backprobe ECU connector F121 and measure voltage between terminals No. 6 and 1 and between terminals No. 6 and 2. If both voltage readings are 0.15-4.85 volts, check for poor ECU connector contact. Repair connector and/or wiring harness as necessary. If either voltage reading is not 0.15-4.85 volts, go to next step.

Turn ignition off. Disconnect air temperature sensor. Measure resistance between air temperature sensor terminals. See the AIR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS table. If resistance is as specified, go to next step. If resistance is not as specified, replace air temperature sensor.

AIR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

Temperature °F (°C)	Ohms
68°F (20°C)	2000-3000
176°F (80°C)	270-370

Disconnect ECU connectors. Measure resistance between ECU connector F121, terminal No. 6 and terminal No. 2 (White/Blue wire) of air temperature sensor connector. Measure resistance between ECU connector F121, terminal No. 1 and terminal No. 1 (Black/Green wire) of air temperature sensor connector. Also, measure resistance between ECU connector F121, terminal No. 2 and terminal No. 2 (Black/Green wire) of air temperature sensor connector. If all resistances are less than one ohm, go to next step. If any resistance is more than one ohm, repair connector and/or wiring harness as necessary.
Measure resistance between ground and ECU connector F121, terminal No. 6. If resistance is infinite, check for poor ECU connector contact. Repair connector and/or wiring harness as necessary. If connector and wiring harness are okay, replace ECU. If resistance is not infinite, repair connector and/or wiring harness as necessary.