37-C1657 IMPLAUSIBLE VARIANT CODING DATA

Code No.C1657: Implausible coding data

caution

If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be stored. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C, CAN Bus Diagnostics Table).
Whenever ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION

EPS-ECU receives variant coding data from the ETACS-ECU.

DIAGNOSTIC TROUBLE CODE SET CONDITION

The abnormal coding data is sent from the ETACS-ECU, and the microcomputer determines that there is a problem in the system.

PROBABLE CAUSES

DIAGNOSIS

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

Use scan tool MB991958 to diagnose the CAN bus lines.

Is the check result normal?

Go to Step 2

Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting

). 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.

Is the diagnostic trouble code stored?

Diagnose the ETACS-ECU (Refer to GROUP 54A - Troubleshooting

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.

Is diagnostic trouble code C1657 stored?

Replace the EPS-ECU (Refer to

). Then go to Step 4

Intermittent malfunction (Refer to GROUP 00 - 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.

Is diagnostic trouble code C1657 stored?

Return to Step 1

This diagnosis is complete.