P0120
NOTE: If both DTC P0120 and DTC P0510 are displayed, 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 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:
ECM Terminals And Reference Value:
On Board Diagnosis Logic:
On Board Diagnosis Logic
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 5 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-II.
2. Start engine and maintain the following conditions for at least 5 consecutive seconds.
VHCL SPEED SE: More than 4 km/h (2 MPH)
Selector lever: Suitable position except "P" or "N" position
3. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.
OR
With Generic Scan Tool
1. Start engine and maintain the following conditions for at least consecutive seconds.
Vehicle speed: More than 4 km/h (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" below.
Procedure for malfunction B
With Consult
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 1,100 rpm, maintain the following conditions for at least 10 seconds to keep engine speed below 1,100 rpm.
A/T model
Selector lever: Suitable position except "P" or "N"
Brake pedal: Depressed
Vehicle speed: 0 km/h (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. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.
OR
With Generic Scan Tool
1. Start engine and let it idle for at least 10 seconds.
If idle speed is over 1,100 rpm, maintain the following conditions for at least 10 seconds to keep engine speed below 1,100 rpm.
A/T model
Selector lever: Suitable position except "P" or "N"
Brake pedal: Depressed
Vehicle speed: 0 km/h (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" below.
Procedure for malfunction C
CAUTION: Always drive vehicle at a safe speed.
With Consult
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" and "HI SPEED" 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 following conditions for at least 10 consecutive seconds.
ENG SPEED: 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" below.
OR
With Generic Scan Tool
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 (47) and ground: More than 3 V
Engine coolant temperature: More than 70 °C (158 °F)
2. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE", .
EC-TPS-01:
EC-TPS-01 Connector View:
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:
Part 2:
Procedure A
Part 1:
Part 2:
Procedure B
Part 1:
Part 2:
Procedure C
COMPONENT INSPECTION
Throttle position sensor
With Consult
1. Start engine and warm it up to normal operating temperature.
2. Stop engine and turn ignition switch "ON".
3. Select "DATA MONITOR" mode with CONSULT-II.
4. Check voltage of "THRTL POS SEN".
Voltage measurement must be made with throttle position sensor installed in vehicle.
If NG, adjust closed throttle position switch. Refer to "Basic Inspection".
5. If it is impossible to adjust closed throttle position switch in "Basic Inspection", replace throttle position sensor.
OR
Without Consult
1. Start engine and warm it up to normal operating temperature.
2. Stop engine and turn ignition switch "ON".
3. Check voltage between ECM terminal (23) (Throttle position sensor signal) and ground.
Voltage measurement must be made with throttle position sensor installed in vehicle.
If NG, adjust closed throttle position switch. Refer to "Basic Inspection".
4. If it is impossible to adjust closed throttle position switch in "Basic Inspection", replace throttle position sensor.