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DTC P1231: Active Stability Control Plausibility <Vehicles with ASC>
 
 
 
 
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 stored are: )
  • Active stability control system failed.
  • ECM failed.
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: Vehicles Communication Interface (V.C.I.)
    • MB991827: M.U.T.-III USB Cable
    • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
STEP 1. Using scan tool (M.U.T.-III), read the diagnostic trouble code (DTC).
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
(1) Connect scan tool (M.U.T-III). Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) .
(2) Turn the ignition switch to the "ON" position.
(3) Read the ASC-DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is ASC-DTC stored?
Refer to GROUP 35C, Diagnosis - Diagnostic Trouble Code Chart .
Go to Step 2.
 
STEP 2. Using scan tool (M.U.T.-III), read the diagnostic trouble code (DTC).
(1) Turn the ignition switch to the "ON" position.
(2) Read the DTC.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Is the diagnostic trouble code other than P1231 stored?
Refer to, Diagnostic Trouble Code Chart .
Go to Step 3.
 
STEP 3. Using scan tool (M.U.T.-III), 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.
Is DTC P1231 stored?
Replace the ECM (Refer to Removal and Installation ).
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 .