The ETCS (Electronic Throttle Control System) has a dedicated power supply circuit. The voltage (+BM) is monitored and when it is low (less than 4 V), the ECM determines that there is a malfunction in the ETCS and cuts off the current to the throttle actuator.
When the voltage becomes unstable, the ETCS itself becomes unstable. For this reason, when the voltage is low, the current to the throttle actuator is cut off. If repairs are made and the system returns to normal, turn the ignition switch to OFF. The ECM then allows the current to flow to the throttle actuator so that it can be restarted.
The ETCS does not use a throttle cable.
|DTC No.||DTC Detection Conditions||Trouble Areas|
Open in Electronic Throttle Control System (ETCS) power source (+BM) circuit
(1 trip detection logic)
The ECM monitors the battery supply voltage applied to the throttle actuator.
When the power supply voltage (+BM) drops below 4 V for 0.8 seconds or more, the ECM interprets this as an open in the power supply circuit (+BM). The ECM illuminates the MIL and sets the DTC.
If the malfunction is not repaired successfully, the DTC is set 5 seconds after the engine is next started.
When this DTC, as well as other DTCs relating to ETCS (Electronic Throttle Control System) malfunctions, is set, the ECM enters fail-safe mode. During fail-safe mode, the ECM cuts the current to the throttle actuator, and the throttle valve is returned to a 6.5° throttle angle by the return spring. The ECM then adjusts the engine output by controlling the fuel injection (intermittent fuel-cut) and ignition timing, in accordance with the accelerator pedal opening angle, to allow the vehicle to continue at a minimal speed. If the accelerator pedal is fully depressed slowly, the vehicle can be driven slowly.
Fail-safe mode continues until a pass condition is detected, and the ignition switch is then turned to OFF.
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
READ VALUE USING INTELLIGENT TESTER (+BM VOLTAGE)
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / +BM Voltage.
Read the value displayed on the tester.
|11 to 14 V|
CHECK HARNESS AND CONNECTOR (ECM - BATTERY, BODY GROUND) Click here
CHECK HARNESS AND CONNECTOR (ECM - BATTERY, BODY GROUND)
Rear view of wire harness connector
Disconnect the ECM connectors.
Measure the voltage according to the value(s) in the table below.
Measure the resistance according to the value(s) in the table below.
Reconnect the ECM connectors.
REPAIR OR REPLACE HARNESS OR CONNECTOR