P0123
DTC P0123: Throttle Position Sensor Circuit High InputThrottle Position Sensor (TPS) Circuit Part 1:
Throttle Position Sensor (TPS) Circuit Part 2:
CIRCUIT OPERATION
- A 5-volt power supply is applied on the TPS power terminal (terminal No. 4) from the ECM (terminal No. 42)
The ground terminal (terminal No. 1) is grounded with ECM (terminal No. 49)
- When the throttle valve shaft is turned from the idle position to the fully opened position, the resistor between the TPS output terminal (terminal No. 3) and ground terminal will increase according to the rotation.
TECHNICAL DESCRIPTION
- The TPS outputs voltage which corresponds to the throttle valve opening angle.
- The ECM
DESCRIPTIONS OF MONITOR METHODS
Throttle position sensor (main) output voltage is out of specified range.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored )
- Not applicable
Sensor (The sensor is determined to be normal)
- Not applicable
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- 2 seconds or more have passed since the starting sequence was completed.
- Engine speed is lower than 1,000 r/min.
- Volumetric efficiency is lower than 60 percent.
Judgement Criteria
- TPS output voltage has continued to be 2 volts or higher for 2 seconds.
OBD-II DRIVE CYCLE PATTERN
None.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- TPS failed or maladjusted.
- Open or shorted TPS circuit harness damage, or connector damage.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
STEP 1. Using scan tool MB991958, check data list item 14: Throttle Position Sensor.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991958 to the data reading mode for item 14, Throttle Position Sensor.
- With the throttle valve in the idle position, voltage should be between 0.535 and 0.735 volt.
- With the throttle valve in the full-open position, voltage should be between 4.5 and 5.5 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: It can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/ Inspection Service Points.
NO: Go to Step 2.
STEP 2. Check connector B-07 at throttle position sensor for damage.
Q: Is the connector in good condition?
YES: Go to Step 3.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 8.
STEP 3. Check the continuity at throttle position sensor harness side connector B-07.
1. Disconnect the connector B-07 and measure at the harness side.
2. Measure the continuity between terminal No. 1 and ground.
- Should be less than 2 Ohms.
Q: Is the continuity normal?
YES: Go to Step 6.
NO: Go to Step 4.
STEP 4. Check connector C-58 at ECM
Q: Is the connector in good condition?
YES: Go to Step 5.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 8.
STEP 5. Check for open circuit and harness damage between throttle position sensor connector B-07 (terminal No. 1) and ECM connector C-58 (terminal No. 49)
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. Then go to Step 8.
NO: Repair it. Then go to Step 8.
STEP 6. Check the throttle position sensor.
1. Disconnect the connector B-07.
2. Measure the resistance between throttle position sensor side connector terminal No. 1 and No. 4.
Standard value: 3.5 - 6.5 kOhms
3. Measure resistance between the throttle position sensor side connector terminal No. 1 and No. 3.
4. Move the throttle valve from the idle position to the full-open position.
- Resistance should change smoothly in proportion to the opening angle of the throttle valve.
Q: Is the resistance between 3.5 and 6.5 kOhms?
YES: Go to Step 7.
NO: Replace the throttle position sensor. Refer to Throttle Body. Then go to Step 8.
STEP 7. Using scan tool MB991958, check data list item 14: Throttle Position Sensor.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991958 to the data reading mode for item 14, Throttle Position Sensor.
- With the throttle valve in the idle position, voltage should be between 0.535 and 0.735 volt.
- With the throttle valve in the full-open position, voltage should be between 4.5 and 5.5 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: It can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points.
NO: Replace the ECM or PCM. Then go to Step 8.
STEP 8. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0123 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.