DTC C1203/59 ECM Communication Circuit Malfunction; DTC C1270/88 Initialization Incomplete (Test Mode DTC): Description

WARNING: This page is about a different car, the 2006 Lexus IS 350. However, it is still accessible from the selected car via links, so may be relevant.

The circuit is used to send TRAC and VSC control information from the skid control ECU to the ECM, and engine control information from the ECM to the skid control ECU.
If the skid control ECU is replaced or if the memory is cleared, the system information such as the destination or vehicle type will be unconfirmed. After switching to the Test Mode, the skid control ECU performs initialization when starting communication with the vehicle, and stores the system information in 2 or 3 seconds. DTC C1270/88 can be cleared when the initialization is completed normally or the Test Mode ends. DTC C1270/88 is output only in the Test Mode.

DIAGNOSIS TROUBLE CODE CHART

DTC No.	DTC Detection Condition	Trouble Area
C1203/59	Engine, drive source and destination variations that are sent from the ECM do not match the ones of the skid control ECU or there is no information in the memory.	ECM

NOTE: When replacing the skid control ECU, perform zero point calibration (See CALIBRATION ).

CHECK PART NUMBER (ECM)
1. Check that the part number of the installed ECM is correct.
  OK: ECM installed in the vehicle has correct part number.
NG : REPLACE ECM

OK : GO TO NEXT STEP
CLEAR AND STORE SYSTEM INFORMATION
1. Clear the system information (See CALIBRATION ).
2. Store the system information (See CALIBRATION ).
NEXT

RECONFIRM DTC

Clear the DTC (See DTC CHECK / CLEAR ).

Check if the same DTC is recorded (See DTC CHECK / CLEAR ).

Result

CONDITION CHART

Condition	Proceed to
DTC (C1203/59) is not output	A
DTC (C1203/59) is output	B

B : REPLACE SKID CONTROL ECU

A : USE SIMULATION METHOD TO CHECK