P0120
NOTE: If DTC P0120 (0403) is displayed with DTC P0510 (0203), perform TROUBLE DIAGNOSIS FOR DTC P0510 first.
COMPONENT DESCRIPTION
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 one 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 REFERENCE VALUE IN DATA MONITOR MODE
Specification data are reference values.
ECM TERMINALS AND REFERENCE VALUE
Specification data are reference values, and are measured between each terminal and (25) (ECM ground).
ON BOARD DIAGNOSIS LOGIC
FAIL-SAFE MODE
When the ECM enters the fail-safe mode, the MIL illuminates.
Perform "Procedure for malfunction A" first. If the DTC cannot be confirmed, perform "Procedure for malfunction B". If there is no problem on "Procedure for malfunction B", perform "Procedure for malfunction C".
DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE
NOTE: If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 10 seconds before conducting the next test.
Procedure for malfunction A
CAUTION: Always drive vehicle at a safe speed.
TESTING CONDITION:
- Before performing the following procedure, confirm that battery voltage is more than 10 V at idle.
- This test may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road test is expected to be easier, it is unnecessary to lift the vehicle.
With Consult
1. Turn ignition switch "ON" and select "DATA MONITOR" mode with CONSULT.
2. Start engine and maintain the following conditions for at least 5 consecutive seconds.
VHCL SPEED SE: More than 4 KPH (2 MPH)
Selector lever: Suitable position except "P" or "N" position
3. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".
OR
With Generic Scan Tools
1. Start engine and maintain the following conditions for at least 5 consecutive seconds.
Vehicle speed: More than 4 KPH (2 MPH)
Selector lever: Suitable position except "P" or "N" position
2. Select "MODE 7" with GST.
3. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".
OR
Without Scan Tools
1. Start engine and maintain the following conditions for at least 5 consecutive seconds.
Vehicle speed: More than 4 KPH (2 MPH)
Selector lever: Suitable position except "P" or "N" position
2. Turn ignition switch "OFF" and wait at least 10 seconds.
3. Turn ignition switch "ON" and perform "DIAGNOSTIC TEST MODE (Self-diagnostic results)" with ECM.
4. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".
Procedure for malfunction B
With Consult
1. Turn ignition switch "ON".
2. Select "DATA MONITOR" mode with CONSULT.
3. Start engine and let it idle for at least 10 seconds.
If idle speed is over 1,000 rpm, maintain the following conditions for at least 10 seconds to keep engine speed below 1,000 rpm.
A/T model
Selector lever: Suitable position except "P" or "N" Brake pedal: Depressed
Vehicle speed: 0 KPH (0 MPH)
M/T model
Selector lever: Suitable position except "N"
(Higher gear position such as 3rd or 4th position is better to keep engine rpm low.)
Accelerator pedal: Released
Vehicle speed: As slow as possible
4. It 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".
OR
With Generic Scan Tools
1. Start engine and let it idle for at least 10 seconds.
If idle speed is over 1,000 rpm, maintain the following conditions for at least 10 seconds to keep engine speed below 1,000 rpm.
A/T model
Selector lever: Suitable position except "P" or "N" Brake pedal: Depressed
Vehicle speed: 0 KPH (0 MPH)
M/T model
Selector lever: Suitable position except "N"
(Higher gear position such as 3rd or 4th position is better to keep engine rpm low.)
Accelerator pedal: Released
Vehicle speed: As slow as possible
2. Select "MODE 7" with GST.
3. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".
OR
Without Scan Tools
1. Start engine and let it idle for at least 10 seconds.
If idle speed is over 1,000 rpm, maintain the following conditions for at least 10 seconds to keep engine speed below 1,000 rpm.
A/T model
Selector lever: Suitable position except "P" or "N"
Brake pedal: Depressed
Vehicle speed: 0 KPH (0 MPH)
M/T model
Selector lever: Suitable position except "N"
(Higher gear position such as 3rd or 4th position is better to keep engine rpm low.)
Accelerator pedal: Released
Vehicle speed: As slow as possible
2. Turn ignition switch "OFF" and wait at least 10 seconds.
3. Turn ignition switch "ON" and perform "Diagnostic Test Mode II (Self-diagnostic results)" with ECM.
4. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".
Procedure for malfunction C
CAUTION: Always drive vehicle at a sale speed.
With Consult
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 10 seconds.
3. Turn ignition switch "ON".
4. Select "MANU TRIG" and "HI SPEED" in "DATA MONITOR" mode with CONSULT.
5. Select "THRTL POS SEN" and "ABSOL TH.P/S" in "DATA MONITOR" mode with CONSULT.
6. Press RECORD on CONSULT 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". If OK, go to following step.
8. Select "AUTO TRIG" in "DATA MONITOR" mode with CONSULT.
9. Maintain the following conditions for at least 10 consecutive seconds.
CKPS.RPM (POS): More than 2,000 rpm
MAS AIR/FL SE: More than 3 V
COOLAN TEMP/S: More than 70 °C (158 °F)
Selector lever: Suitable position
Driving location: Driving vehicle uphill (Increased engine load) will help maintain the driving conditions required for this test.
10. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".
OR
With Generic Scan Tools
1. Maintain the following conditions for at least 10 consecutive seconds.
Gear position: Suitable position
Engine speed: More than 2,000 rpm
Voltage between ECM terminal (54) and ground: More than 3 V
Voltage between ECM terminal (59) and ground: Less than 1.5 V
2. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".
OR
Without Scan Tools
1. Maintain the following conditions for at least 10 consecutive seconds.
Gear position: Suitable position
Engine speed: More than 2,000 rpm
Voltage between ECM terminal (54) and ground: More than 3 V
Voltage between ECM terminal (59) and ground: Less than 1.5 V
2. Stop the vehicle, turn ignition switch "OFF", wait at least 10 seconds and then turn "ON".
3. Perform "DIAGNOSTIC TEST MODE (Self-diagnostic results)" with ECM.
4. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".
WIRING DIAGRAM
DIAGNOSTIC PROCEDURE
If the trouble is duplicated after "Procedure for malfunction A", perform "Procedure A" below. If the trouble is duplicated after "Procedure for malfunction B", perform "Procedure B". If the trouble is duplicated after "Procedure for malfunction C", perform "Procedure C".
Part 1 Of 2:
Procedure A
Part 2 Of 2:
Procedure B
Part 1 Of 2:
Part 2 Of 2:
Procedure C
COMPONENT INSPECTION
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF".
3. Disconnect throttle position sensor harness connector.
4. Make sure that resistance between terminals (2) and (3) changes when opening throttle valve manually.
NOTE: Resistance measurement must be made with throttle position sensor installed in vehicle.
If NG, replace throttle position sensor.
To adjust throttle position sensor, perform "Basic Inspection".