2010 Lexus Truck RX 350 AWD V6-3.5L (2GR-FE) P Code Charts Page 469

6. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

(a) Disconnect the mass air flow meter sub-assembly connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Text in Illustration

(d) Reconnect the mass air flow meter sub-assembly connector.

(e) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

OK -- REPLACE ECM See: Powertrain Management/Computers and Control Systems/Engine Control Module/Service and

Repair/Removal

Up to 08/2009

2GR-FE ENGINE CONTROL: SFI SYSTEM: P0102,P0103: Mass or Volume Air Flow Circuit Low Input

DESCRIPTION

The mass air flow meter sub-assembly is a sensor that measures the amount of air flowing through the throttle valve.

The ECM uses this information to determine the fuel injection time and to provide the appropriate air fuel ratio.

Inside the mass air flow meter sub-assembly, there is a heated platinum wire which is exposed to the flow of intake air.

By applying a specific electrical current to the wire, the ECM heats it to a given temperature. The flow of incoming air cools both the wire and an

internal thermistor, affecting their resistance. To maintain a constant current value, the ECM varies the voltage applied to these components in the

mass air flow meter sub-assembly. The voltage level is proportional to the air flow through the sensor, and the ECM uses it to calculate the intake air

volume.

The circuit is constructed so that the platinum hot wire and the temperature sensor create a bridge circuit, and the power transistor is controlled so

that the potentials of A and B remain equal to maintain the predetermined temperature.

HINT

When any of these DTCs are set, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is calculated by the

ECM, according to the engine speed and throttle valve position. Fail-safe mode continues until a pass condition is detected.