P1600

DTC P1600 BACK-UP POWER SOURCE CIRCUIT MALFUNCTION

CIRCUIT DESCRIPTION

DTC Detecting Condition:

Battery positive voltage is applied to terminal BATT of the ECM even when the ignition switch is OFF for use by the DTC memory and air-fuel ratio adaptive control value memory, etc.

HINT: If DTC P1600 is displayed, the ECM does not store another DTC.

Wiring Diagram:

Steps 1 - 2:

INSPECTION PROCEDURE

HINT: Read freeze frame data using LEXUS hand-held tester or OBD II scan tool, as freeze frame data records the engine conditions when the 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 air-fuel ratio was lean or rich, etc. at the time of the malfunction.