Code No. C1657: Implausible coding data: Diagnosis

STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.
Use scan tool MB991958 to diagnose the CAN bus lines.

Q: Is the check result normal?
1. YES: Go to Step 2.
2. NO: Repair the CAN bus lines (Refer to CAN BUS DIAGNOSTICS TABLE ). On completion, go to Step 2.
STEP 2. Use scan tool MB991958 to confirm a diagnostic trouble code of other systems.
Check if the ETACS-ECU stores a diagnostic trouble code.

Q: Is the diagnostic trouble code stored?
1. YES: Diagnose the ETACS-ECU (Refer to DIAGNOSTIC TROUBLE CODE TABLE ).
2. NO: Go to Step 3.
STEP 3. Check whether the diagnostic trouble code is stored again.
1. Erase the diagnostic trouble code.
2. Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
3. Check if the diagnostic trouble code is stored.
Q: Is diagnostic trouble code C1657 stored?
1. YES: Replace the EPS-ECU (Refer to STEERING COLUMN SHAFT ASSEMBLY ). Then go to Step 4.
2. NO: Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
STEP 4. Check whether the diagnostic trouble code is stored again.
1. Erase the diagnostic trouble code.
2. Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
3. Check if the diagnostic trouble code is stored.
Q: Is diagnostic trouble code C1657 stored?
1. YES: Return to Step 1.
2. NO: This diagnosis is complete.