P1234
DTC P1234: Throttle Position Sensor (Sub) PlausibilityTECHNICAL DESCRIPTION
Compare the actual measurement of volumetric efficiency by a mass airflow sensor signal with volumetric efficiency estimated from a throttle position sensor (sub) signal.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Not applicable
DTC SET CONDITIONS
Logic Flow Chart
Logic Flow Chart:
Check Conditions
- The engine speed is between 750 and 3,000 r/min. Or, the throttle position sensor (main) output voltage is 3 volts or lower.
- Except while fuel is being shut off.
Judgment Criterion
- For 0.8 second, the difference between the actual volumetric efficiency and the volumetric efficiency estimated by the throttle position sensor (sub) is 43 percent or more.
FAIL-SAFE AND BACKUP FUNCTION
- Throttle opening degree is restricted.
- Throttle opening degree position is in default position if throttle position sensor (main) fails.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 16. OBD- II Drive Cycle
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Throttle position sensor (sub) system failed.
- Intake system vacuum leak.
- ECM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
- MB991658: Test Harness
STEP 1. Using scan tool MB991958, read the diagnostic trouble code (DTC).
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. Read the DTC.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the diagnostic trouble code other than P1234 set?
YES : Refer to, Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions
NO : Go to Step 2.
STEP 2. Using scan tool MB991958, check data list item 15: Throttle Position Sensor (sub).
1. Turn the ignition switch to the "ON" position.
2. Detach the intake air hose at the throttle body.
3. Disconnect the connector of the throttle position sensor.
4. Use test harness special tool (MB991658) to connect only terminals No. 3, No. 4, No. 5, and No. 6.
5. Set scan tool MB991958 to the data reading mode for item 15, Throttle Position Sensor (sub).
- Output voltage should be 4.0 volts or more when the throttle valve is fully closed with your finger.
- Output voltage should be 1.0 volt or less when the throttle valve is fully open with your finger.
6. 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.
NO : Go to Step 3.
STEP 3. Check for intake system vacuum leak.
Q: Are there any abnormalities?
YES : Repair it. Then go to Step 5.
NO : Go to Step 4.
STEP 4. Check the trouble symptoms.
1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 16. OBD- II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P1234 set?
YES : Replace the ECM. When the ECM is replaced, register the ID code. The go to Step 5.
NO : It can be assumed that this malfunction is intermittent.
STEP 5. 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 - Pattern 16. OBD- II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P1234 set?
YES : Retry the troubleshooting.
NO : The inspection is complete.