EINE (RZFE, 3RZFE) DI33 DII3 DTC P00 Intake Air Temperature Circuit Malfunction CIRCUIT DESCRIPTION Resistance kω Fig. 30 0 0 5 3 0.5 0.3 0. 0. Acceptable 0 0 0 40 60 80 00 ( 4) 3 68 04 40 76 Temp. C (F ) The intake air temperature sensor is built into mass air flow meter and senses the intake air temperature. A thermistor built in the sensor changes the resistance value according to the intake air temperature. The lower the intake air temperature, the greater the thermistor resistance value, and the higher the intake air temperature, the lower the thermistor resistance value (See Fig. ). The intake air temperature sensor is connected to the (See below). The power source voltage in the is applied to the intake air temperature sensor from terminal via a resistor R. That is, resistor R and the intake air temperature sensor are connected in series. When the resistance value of the intake air temperature sensor changes in accordance with changes in the intake air temperature, the potential at terminal also changes. Based on this signal, the increases the fuel injection volume to improve driveability during cold engine operation. FI474 DTC No. DTC Detection Condition Trouble Area Open or short in intake air temp. sensor circuit P00 Open or short in intake air temp. sensor circuit Intake air temp. sensor (built into mass air flow meter) After confirming DTC P0, use the handheld tester or the OBD II scan tool to confirm the intake air temperature from the DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL. Temperature Displayed 40 C (40 F) Malfunction Open circuit 40 C (84 F) or more Short circuit 003 TOYOTA TACOMA (RM00U) 95
DI34 DIAGNOSTICS EINE (RZFE, 3RZFE) WIRI DIAGRAM Intake Air temperature (Built into Mass Air Flow Meter) YG R LB 8 E A0030 A0977 INSPECTION PROCEDURE If different DTCs that are related to different systems are output simultaneously while terminal E is used as a ground terminal, terminal E may be open. Read freeze frame data using the handheld tester or the OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the airfuel ratio was lean or rich, etc. at the time of the malfunction. Connect handheld tester or OBD II scan tool, and read value of intake air temperature. (a) Connect the handheld tester or OBD II scan tool to DLC3. (b) Turn the ignition switch ON and push the handheld tester or OBD II scan tool main switch ON. (c) Select the item DIAGNOSIS/ENHANCED OBD II/DATA Read the temperature value on the handheld tester or the OBD II scan tool. : Same value as the actual intake temperature. If there is open circuit, handheld tester or OBD II scan tool indicates 40 C (40 F). If there is short circuit, handheld tester or OBD II scan tool indicates 40 C (84 F) or more. 40 C (40 F)... Go to step. 40 C (84 F) or more... Go to step 4. Check for intermittent problems (See page DI3). 003 TOYOTA TACOMA (RM00U) 96
EINE (RZFE, 3RZFE) DI35 Check for open in harness or. 8 E E A750 (b) Connect the sensor wire harness terminals together. (c) Turn the ignition switch ON. (d) Select the item DIAGNOSIS/ENHANCED OBD II/DATA Read the temperature value on the handheld tester or the OBD II scan tool. : Temperature value: 40 C (84 F) or more Confirm good connection at sensor. If, replace mass air flow meter. 3 Check for open in harness or. E 8 E E (b) Remove the glove compartment (See page SF55). (c) Connect between terminals and E of the connector. The mass air flow meter connector is disconnected. Before checking, do a visual and contact pressure check for the connector (See page IN8). (d) Turn the ignition switch ON. (e) Select the item DIAGNOSIS/ENHANCED OBD II/DATA Read the temperature value on the handheld tester or the OBD II scan tool. : Temperature value: 40 C (84 F) or more A75 A8845 A8853 Open in harness between terminal E or, repair or replace harness. 003 TOYOTA TACOMA (RM00U) 97
DI36 DIAGNOSTICS EINE (RZFE, 3RZFE) Confirm good connection at. If, replace. 4 Check for short in harness and. 8 E E A75 (b) Turn the ignition switch ON. (c) Select the item DIAGNOSIS/ENHANCED OBD II/DATA Read the temperature value on the handheld tester or OBD II scan tool. : Temperature value: 40 C (40 F) Replace mass air flow meter. 003 TOYOTA TACOMA (RM00U) 98
EINE (RZFE, 3RZFE) DI37 5 Check for short in harness or. E E (a) Remove the glove compartment (See page SF55). (b) Disconnect the connector. The mass air flow meter connector is disconnected. (c) Turn the ignition switch ON. (d) Select the item DIAGNOSIS/ENHANCED OBD II/DATA Read the temperature value on the handheld tester or OBD II scan tool. : Temperature value: 40 C (40 F) Connector A378 A0934 A8854 Repair or replace harness or connector. Check and replace (See page IN8). 003 TOYOTA TACOMA (RM00U) 99