Code No. P1221: Throttle Valve Position Feedback System

OPERATION

Controls the current that is applied from the engine-A/T-ECU (terminals No. 133, No. 141) to the electronic-controlled throttle valve (terminals No. 1, No. 2).

FUNCTION

The engine-A/T-ECU controls the throttle valve-opened degree to become the designed open degree.

TROUBLE JUDGMENT

Check Conditions

Ignition switch is in ON position.
Battery voltage is 8.3 V or more.
White the electric currents are going through the throttle valve control servo.
Throttle position sensor (main) output voltage is between 0.2 and 4.8 V.
When the variation in the throttle valve-opened degree is small.

Judgment Criteria

The difference between the throttle position sensor (main) output voltage and the designed one is 0.5 V or more.

PROBABLE CAUSE

Failed throttle valve operation
Failed throttle valve control servo
Open/short circuit in throttle valve control servo circuit or loose connector contact
Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-06 electronic-controlled throttle valve connector

Q. Is the check result normal?

Go to Step 2.

Repair or replace.

STEP 2. Check throttle valve control servo.

Check throttle valve control servo (Refer to ).

Q. Is the check result normal?

	Go to Step 3.

	Replace throttle body assembly.

STEP 3. Connector check: C-114 engine-A/T-ECU connector

Q. Is the check result normal?

Go to Step 4 .

Repair or replace.

STEP 4. Check harness between B-06 (terminal No. 1) electronic-controlled throttle valve connector and C-114 (terminal No. 133) engine-A/T-ECU connector.

Check output line for damage.

Q. Is the check result normal?

Go to Step 5 .

Repair.

STEP 5. Check harness between B-06 (terminal No. 2) electronic-controlled throttle valve connector and C-114 (terminal No. 141) engine-A/T-ECU connector.

Check output line for damage.

Q. Is the check result normal?

Go to Step 6 .

Repair.

STEP 6. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	Replace engine-A/T-ECU.

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