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

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 for 0.5 second.

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 for 0.5 second.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function - OBD-II Drive Cycle Pattern 23

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?

Refer to, Diagnostic Trouble Code Chart

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?

	Replace the ECM. When the ECM is replaced, register the ID code. Refer to GROUP 42B, ID Code Registration Necessity Judgment Table <Vehicles with KOS> or GROUP 42C, ID Codes Registration Judgment Table <Vehicles with WCM> . Then go to Step 3.

	It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .

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

(2)Check the diagnostic trouble code (DTC).

Q. Is DTC P1239 set?

	Retry the troubleshooting.

	The inspection is complete.