P1239

DTC P1239: Engine RPM Plausibility

TECHNICAL DESCRIPTION
Compares the actual engine speed calculated from the crankshaft position sensor signal cycle with the estimated engine speed calculated from the number of the crankshaft position sensor signal pulses after a lapse of the specified time.

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 Condition
- The engine speed monitored with a 180 degree-cycle pulse is 500 r/min or more.

Judgment Criterion
- The difference between the engine speed monitored with a 180 degree-cycle pulse and the engine speed monitored with a 10 degree-cycle pulse is 500 r/min or more.

Check Condition
- The engine speed monitored with a 180 degree-cycle pulse is 500 r/min or less.

Judgment Criterion
- The engine speed monitored with a 10 degree-cycle pulse is 1,000 r/min or more.

FAIL-SAFE AND BACKUP FUNCTION
- Throttle opening degree position is in default position.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23. OBD- II Drive Cycle

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Crankshaft position sensor system failed.
- 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

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 P1239 set?

YES : Refer to, Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions

NO : Go to Step 2.

STEP 2. Using scan tool MB991958, read the diagnostic trouble code (DTC).

1. Turn the ignition switch to the "ON" position.
2. After the DTC has been deleted, read the DTC again.
3. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is DTC P1239 set?

YES : Replace the ECM. When the ECM is replaced, register the ID code. Then go to Step 3.

NO : It can be assumed that this malfunction is intermittent.

STEP 3. 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 23. OBD- II Drive Cycle
2. Check the diagnostic trouble code (DTC).

Q: Is DTC P1239 set?

YES : Retry the troubleshooting.

NO : The inspection is complete.