P2118 Open in ETCS power source (+BM) circuit(1 trip detection logic)

DESCRIPTION

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 (Included in HV Control ECU) 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. If repairs are made and the system returns to normal, turn the engine switch to off. The ECM then allows the current to flow to the throttle actuator so that it can be restarted.

HINT:

The ETCS does not use a throttle cable.

DTC No.	DTC Detection Condition	Trouble Area
P2118	Open in ETCS power source (+BM) circuit (1 trip detection logic)	Open in ETCS power source circuit ETCS fuse HV Control ECU

FAIL-SAFE

When this DTC, as well as other DTCs relating to ETCS (Electronic Throttle Control System) malfunctions, is set, the ECM (Included in HV Control ECU) enters fail-safe mode. During fail-safe mode, the ECM cuts the current to the throttle actuator off, and the throttle valve is returned to a 6° 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 depressed firmly and gently, the vehicle can be driven slowly.
Fail-safe mode continues until a pass condition is detected, and the engine switch is then turned to off.

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:

Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.

1. CHECK FUSE (ETCS FUSE)

1. Remove the ETCS fuse from the engine R/B No.4.

2. Check the ETCS fuse resistance.

   Standard resistance:

   Below 1 Ω
   

3. Reinstall the ETCS fuse.

NG	CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE

OK

2. INSPECT HV CONTROL ECU (+BM VOLTAGE)

1. Measure the voltage between the terminals of the H32 and H31 HV Control ECU connectors.

   Standard voltage:

   Tester Connection	Specified Condition
   +BM (H31-3) - ME01 (H32-4)	9 to 14 V

OK	CHECK FOR INTERMITTENT PROBLEMS

NG

3. CHECK HARNESS AND CONNECTOR (HV CONTROL ECU - ETCS FUSE, ETCS FUSE - BATTERY)

1. Check the harness and connector between the ETCS fuse and HV Control ECU.

   1. Remove the ETCS fuse from the engine R/B No.4.

   2. Disconnect the H31 HV Control ECU connector.

   3. Measure the resistance between the terminal of the ETCS fuse and HV Control ECU.

      Standard resistance (Check for open):

      Tester Connection	Specified Condition
      ETCS fuse (2) - +BM (H31-3)	Below 1 Ω

      Standard resistance (Check for short):

      Tester Connection	Specified Condition
      ETCS fuse (2) or +BM (H31-3) - Body ground	10 kΩ or higher

   4. Reinstall the ETCS fuse.

   5. Reconnect the HV Control ECU connector.

2. Check the harness and connector between the ETCS fuse and positive battery cable.

   1. Remove the ETCS fuse from the engine R/B No.4.

   2. Disconnect the positive battery cable.

   3. Measure the resistance between the ETCS fuse and battery.

      Standard resistance (Check for open):

      Tester Connection	Specified Condition
      Positive battery cable - ETCS fuse (1)	Below 1 Ω

      Standard resistance (Check for short):

      Tester Connection	Specified Condition
      Positive battery cable or ETCS fuse (1) - Body ground	10 kΩ or higher

   4. Reinstall the ETCS fuse.

   5. Reconnect the positive battery cable.

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
REPLACE HV CONTROL ECU