DTC P1231: Active Stability Control Plausibility

TECHNICAL DESCRIPTION

Checks for an abnormal signal of active stability control (ASC) via the CAN communication.

DTC SET CONDITIONS

Check Condition

Ignition switch is "ON" position.

Judgment Criterion

A torque demand signal from the active stability control is not normal.

FAIL-SAFE AND BACKUP FUNCTION

Torque requested by active stability control (ASC) is ignored.

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)

Active stability control 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 DTC P1231 set?

Go to Step 2.

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 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 ASC-DTC.

(3)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the ASC-DTC set?

	Refer to GROUP 35C, Diagnosis - Diagnostic Trouble Code Chart .

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