Code No. P0122: Throttle Position Sensor (Main) Circuit Low Input <3A9>

OPERATION

A power voltage of 5 V is applied to the electronic-controlled throttle valve (terminal No. 5) from the engine-ECU (terminal No. 31).
The power voltage is earthed to the engine-ECU (terminal No. 30) from the electronic-controlled throttle valve (terminal No. 3).
The sensor signal is inputted to the engine-ECU (terminal No. 15) from the electronic-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-ECU.
The engine-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 0.35 V or less for 0.5 second.

PROBABLE CAUSES

Failed throttle position sensor (main)
Open or shorted throttle position sensor (main) circuit, harness damage, or connector damage
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

Refer to Data List Reference Table .

Item No. 13: Throttle position sensor (main)

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Go to Step 2 .

STEP 2. Connector check: A-118 electronic-controlled throttle valve connector and A-08 engine-ECU connector

Q. Are the check results normal?

Go to Step 3 .

Repair or replace the connector.

STEP 3. Check harness between A-118 (terminal No. 5) electronic-controlled throttle valve connector and A-08 (terminal No. 31) engine-ECU connector.

Check power supply line for damage.

Q. Is the check result normal?

Go to Step 4 .

Repair the damaged harness wire.

STEP 4. Check harness between A-118 (terminal No. 4) electronic-controlled throttle valve connector and A-08 (terminal No. 15) engine-ECU connector.

Check output line for short circuit.

Q. Is the check result normal?

Go to Step 5 .

Repair the damaged harness wire.

STEP 5. M.U.T.-III data list

Refer to Data List Reference Table .

Item No. 13: Throttle position sensor (main)

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Go to Step 6 .

STEP 6. Replace the throttle body assembly

After replacing the throttle body assembly, reconfirm whether the diagnosis code is set.

Q. Is the diagnosis code set?

	Replace the engine-ECU then perform the variant coding (Refer to GROUP 00 - Precautions Before Service - How to Perform Variant Coding ).

	Check end.