37-C1550 ECU INTERNAL ERROR

DTC C1550 ECU internal error

caution

If there is any problem in the CAN bus lines, an incorrect DTC may be set. 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

FUNCTION

The motor current is controlled according to the information on motor and resolver, and the information on CAN bus.

TROUBLE JUDGMENT

Judgment Criterion

The system data is out of the prestored control range, and the microcomputer determines that there is an internal problem.

Fail Safe, Back Up Function

The electric power steering-ECU stops the motor control and illuminates the electric power steering warning symbol, then sets DTC C1550.

PROBABLE CAUSES

DIAGNOSIS

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

Use scan tool to diagnose the CAN bus lines.

Is the check result normal?

Go to Step 3

Repair the CAN bus lines (Refer to GROUP 54C - Diagnosis/CAN Bus Diagnostics Table

). On completion, go to Step 2

STEP 2. DTC recheck after resetting CAN bus lines

(1) Erase the DTC.

(2) Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.

(3) Check if the DTC is set.

Is DTC C1550 set?

Go to Step 3

This diagnosis is complete.

STEP 3. Check whether the DTC is set again.

(1) Erase the DTC.

(2) Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.

(3) Check if the DTC is set.

Is DTC C1550 set?

Replace the electric power steering-ECU (Refer to

).Then go to Step 4

Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions

STEP 4. Check whether the DTC is set again.

(1) Erase the DTC.

(2) Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.

(3) Check if the DTC is set.

Is DTC C1550 set?

Return to Step 1

This diagnosis is complete.