STEP 3. Measure the power supply voltage at ECM connector by using power plant ECU check harness special tool MB992110.
(1) Disconnect all ECM connectors. Connect the power plant ECU check harness special tool MB992110 between the separated connectors.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal LHFR and ground.- Voltage should be battery positive voltage.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 4. Repair or replace the connector(s), or check and repair the harness of short to ground and open circuit in LHFR line between right bank linear air-fuel ratio sensor connector and ECM connector. Then go to Step 7.