P0121

DTC P0121 TP SENSOR




Component Description

NOTE: If DTC P0121 is displayed with DTC P0510, first perform the trouble diagnosis for DTC P0510. Refer to DTC P0510.

The throttle position sensor responds to the accelerator pedal movement. This sensor is a kind of potentiometer which transforms the throttle position into output voltage, and emits the voltage signal to the ECM. In addition, the sensor detects the opening and closing speed of the throttle valve and feeds the voltage signal to the ECM.

Idle position of the throttle valve is determined by the ECM receiving the signal from the throttle position sensor. This sensor controls engine operation such as fuel cut. On the other hand, the "Wide open and closed throttle position switch", which is built into the throttle position sensor unit, is not used for engine control.

CONSULT-II Reference Value In Data Monitor Mode:

On Board Diagnosis Logic:

DTC Confirmation Procedure

NOTE:
- Perform "PROCEDURE FOR MALFUNCTION A" first. If the 1st trip DTC cannot be confirmed, perform "PROCEDURE FOR MALFUNCTION B".
- If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch OFF and wait at least 5 seconds before conducting the next test.

PROCEDURE FOR MALFUNCTION A

With CONSULT-II
1. Turn ignition switch "ON".




2. Select "DATA MONITOR" mode with CONSULT-II.




3. Start engine and let it idle for at least 10 seconds.
If idle speed is over 1,000 rpm, maintain the given conditions for at least 10 seconds to keep engine speed below 1,000 rpm.
4. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.

With GST
Follow the procedure "With CONSULT-II".

PROCEDURE FOR MALFUNCTION B

CAUTION: Always drive vehicle at a safe speed.

With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds.
3. Turn ignition switch "ON".
4. Select "MANU TRIG" in "DATA MONITOR" mode with CONSULT-II.




5. Select "THRTL POS SEN" and "ABSOL TH.P/S" in "DATA MONITOR" mode with CONSULT-II.
6. Press RECORD on CONSULT-II SCREEN at the same time accelerator pedal is depressed.




7. Print out the recorded graph and check the following:
- The voltage rise is linear in response to accelerator pedal depression.
- The voltage when accelerator pedal is fully depressed is approximately 4 V.
If NG, go to "Diagnostic Procedure" below.
If OK, go to following step.




8. Select "AUTO TRIG" in "DATA MONITOR" mode with CONSULT-II.




9. Maintain the given conditions for at least 10 consecutive seconds.
10. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.

With GST
Follow the procedure "With CONSULT-II".

EC-TPS-01:

Wiring Diagram


Diagnostic Procedure

Diagnostic Procedure Step 1 - 3:

Diagnostic Procedure Step 4 - 7:

Diagnostic Procedure Step 8 - 11:

Diagnostic Procedure Step 12 - 14:

Component Inspection

THROTTLE POSITION SENSOR

With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Stop engine (ignition switch OFF).
3. Turn ignition switch ON.




4. Select "DATA MONITOR" mode with CONSULT-II.




5. Check voltage of "THRTL POS SEN" under the given conditions.
Voltage measurement must be made with throttle position sensor installed in vehicle.

With GST
1. Start engine and warm it up to normal operating temperature.
2. Stop engine (ignition switch OFF).
3. Turn ignition switch ON.




4. Check voltage between ECM terminal 23 (Throttle position sensor signal) and ground.
Voltage measurement must be made with throttle position sensor installed in vehicle.