DTC U0331: ECU internal error: Diagnosis

WARNING: This page is about a different variant/trim than selected.

Required Special Tools:

MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle 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)

Recheck for diagnostic trouble code.

Check again if the DTC is set to the ETACS-ECU.

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.

Connect scan tool MB991958. Refer to "HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) ."
Turn the ignition switch to the "ON" position.
Erase the DTC.
Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
Check if DTC is set.
Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
1. YES: Replace the ETACS-ECU.
2. NO: The diagnosis is complete.
  
  Fig 1: Connecting Special Tool MB991910 To Data Link Connector
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.