Lexus IS250 IS220d GSE20 ALE20 2AD-FHV ENGINE CONTROL SYSTEM

Install a new O-ring to the mass air flow meter.

Remove the 11 clips and intake duct seal.

Perform confirmation driving pattern.

Lexus IS250 IS220d GSE20 ALE20 2AD-FHV ENGINE CONTROL SYSTEM

The MIL (Malfunction Indicator Lamp) is used to indicate malfunction detections by the ECM.

By turning the engine switch on (IG), power is supplied to the MIL circuit, and the ECM provides the circuit ground which illuminates the MIL.

When the engine is cranking, the starter operation signal is sent to the ECM's STA terminal.

A fuel pump is located in the fuel tank and controlled by the ECM. The fuel pump operates only when fuel transfer operation and priming operation are performed.

Fuel transfer operation:

When the fuel level in fuel tank chamber A decreases, the ECM activates the fuel pump to transfer the fuel from chamber B to chamber A to keep the fuel level in chamber A above the specified level.

Priming operation:

The ECM constantly generates 5 V power from the battery voltages supplied to the +B (BATT) terminal to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.

When the engine switch is turned ON (IG), the battery voltage is applied to terminal IGSW of the ECM. The ECM "MREL" output signal causes a current to flow to the coil, closing the contacts of the MAIN relay and supplying power to terminal +B of the ECM.