Code No. P0123: Throttle Position Sensor (Main) Circuit High Input

OPERATION

A power voltage of 5 V is applied to the electronically controlled throttle valve (terminal No. 5) from the engine-A/T-ECU (terminal No. 106).

The power voltage is earthed to the engine-A/T-ECU (terminal No. 105) from the electronically controlled throttle valve (terminal No. 3).

The sensor signal is inputted to the engine-A/T-ECU (terminal No. 115) from the electronically controlled throttle valve output terminal (terminal No. 4).

FUNCTION

The throttle position sensor converts the throttle valve position into voltage and inputs it into the engine-A/T-ECU.

The engine-A/T-ECU controls the throttle valve position.

TROUBLE JUDGMENT

Check Condition

Ignition switch is in "ON" position.

Judgment Criterion

Throttle position sensor (main) output voltage is 4.8 V or more for 0.5 second.

PROBABLE CAUSE

Failed throttle position sensor (main)

Open/short circuit in throttle position sensor circuit or loose connector contact

Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. MUT-II/III data list

Refer to Data List Reference Table .

Item 79: Throttle position sensor (main)

Q: Is the check result normal?

YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points

).
NO: Go to Step 2

STEP 2. Connector check: B-33 electronically controlled throttle valve connector

Q: Is the check result normal?

YES: Go to Step 3

.
NO: Repair.

STEP 3. Perform resistance measurement at B-33 electronically controlled throttle valve connector.

Disconnect connector, and measure at harness side.

Resistance between terminal No. 3 and earth.

OK: 2 Ω or less

Q: Is the check result normal?

YES: Go to Step 7

.
NO: Go to Step 4

STEP 4. Connector check: C-137 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 5

.
NO: Repair.

STEP 5. Check harness between B-33 (terminal No. 3) electronically controlled throttle valve connector and C-137 (terminal No. 105) engine-A/T-ECU connector.

Check earthing line for open circuit and damage.

Q: Is the check result normal?

YES: Go to Step 6

.
NO: Repair.

STEP 6. MUT-II/III data list

Refer to Data List Reference Table .

Item 79: Throttle position sensor (main)

Q: Is the check result normal?

YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points

).
NO: Replace engine-A/T-ECU.

STEP 7. Replace the electronically controlled throttle valve

After replacing the electronically controlled throttle valve, re-check the trouble symptoms.

Q: Is the check result normal?

YES: Check end.
NO: Replace the engine-A/T-ECU.


Code No. P0123: Throttle Position Sensor (Main) Circuit High Input

OPERATION A power voltage of 5 V is applied to the electronically controlled throttle valve (terminal No. 5) from the engine-A/T-ECU (terminal No. 106). The power voltage is earthed to the engine-A/T-ECU (terminal No. 105) from the electronically controlled throttle valve (terminal No. 3). The sensor signal is inputted to the engine-A/T-ECU (terminal No. 115) from the electronically controlled throttle valve output terminal (terminal No. 4).
FUNCTION The throttle position sensor converts the throttle valve position into voltage and inputs it into the engine-A/T-ECU. The engine-A/T-ECU controls the throttle valve position.
TROUBLE JUDGMENT Check Condition Ignition switch is in "ON" position. Judgment Criterion Throttle position sensor (main) output voltage is 4.8 V or more for 0.5 second.
PROBABLE CAUSE Failed throttle position sensor (main) Open/short circuit in throttle position sensor circuit or loose connector contact Failed engine-A/T-ECU
	DIAGNOSIS PROCEDURE

	STEP 1. MUT-II/III data list Refer to Data List Reference Table . Item 79: Throttle position sensor (main) Q: Is the check result normal? YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ). NO: Go to Step 2 .
	STEP 2. Connector check: B-33 electronically controlled throttle valve connector
	Q: Is the check result normal? YES: Go to Step 3 . NO: Repair.
	STEP 3. Perform resistance measurement at B-33 electronically controlled throttle valve connector.
	Disconnect connector, and measure at harness side. Resistance between terminal No. 3 and earth. OK: 2 Ω or less Q: Is the check result normal? YES: Go to Step 7 . NO: Go to Step 4 .
	STEP 4. Connector check: C-137 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 5 . NO: Repair.
	STEP 5. Check harness between B-33 (terminal No. 3) electronically controlled throttle valve connector and C-137 (terminal No. 105) engine-A/T-ECU connector.
	Check earthing line for open circuit and damage. Q: Is the check result normal? YES: Go to Step 6 . NO: Repair.
	STEP 6. MUT-II/III data list Refer to Data List Reference Table . Item 79: Throttle position sensor (main) Q: Is the check result normal? YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ). NO: Replace engine-A/T-ECU.
	STEP 7. Replace the electronically controlled throttle valve After replacing the electronically controlled throttle valve, re-check the trouble symptoms. Q: Is the check result normal? YES: Check end. NO: Replace the engine-A/T-ECU.