Examination
1. On 4-cylinder engines, disconnect the connector from the sensor, which is located inside the air filter, check the resistance of the sensor at different temperatures (See table Resistance values of serviceable intake air and coolant temperature sensors at various temperatures on 4-cylinder engines), blowing on the sensor, for example, with a hair dryer. If the sensor resistance changes disproportionately with temperature, it should be replaced.
2. On 6-cylinder engines, disconnect the connector from the sensor, check the resistance of the sensor at different temperatures by connecting an ohmmeter to terminals 4 and 5 of the sensor, and compare with the table (see table Resistance values of serviceable intake air and coolant temperature sensors at various temperatures on 6-cylinder engines). If the sensor resistance does not correspond to the table value, it should be replaced.
Resistance values of serviceable intake air and coolant temperature sensors at various temperatures on 4-cylinder engines
| Temperature,°C | Resistance, Ohm |
| 100 | 125 |
| 90 | 250 |
| 80 | 300 |
| 70 | 400 |
| 60 | 500 |
| 50 | 625 |
| 45 | 750 |
| 40 | 875 |
| 35 | 1000 |
| 30 | 1500 |
| 25 | 2000 |
| 20 | 2500 |
| 15 | 3000 |
| 10 | 3500 |
| 4,5 | 4000 |
| 0 | 4500 |
Resistance values of serviceable intake air and coolant temperature sensors at various temperatures on 6-cylinder engines
| Contact | Resistance, Ohm | Temperature,°C |
| 5 – 4 | 13,6 – 18,4 | –20 |
| 5 – 4 | 2,21 – 2,69 | 20 |
| 5 – 4 | 0,49 – 0,67 | 60 |
Replacement (4-cylinder engines)
(The material is republished from an online website: «toyotaman»)
Attention! On 6-cylinder engines, the IAT sensor is implemented in a single module with the air flow sensor.
1. Turn off the ignition.
2. Disconnect the connector and remove the sensor.