Code No. P1221: Throttle Valve Position Feedback System

OPERATION

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

FUNCTION

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

TROUBLE JUDGMENT

Check Conditions

Ignition switch is in “ON” position.
The battery voltage is 8.3 V or more
While the electric currents are going through the throttle valve servo
The output voltage of the throttle position sensor (main) is 0.2 V or more, and 4.8 V or less.

Judgment Criteria

When the variation in the throttle valve-opened degree is small.

or

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-ECU <M/T>
Failed engine-A/T-ECU <A/T>

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-ECU <M/T> connector or engine-A/T-ECU <A/T> 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-ECU <M/T> connector or engine-A/T-ECU <A/T> 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-ECU <M/T> connector or engine-A/T-ECU <A/T> 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-ECU<M/T> or engine-A/T-ECU.

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