Power Assist Systems

Assist Map Number Un-Writing (C1581)

~2min read
DESCRIPTION

The power steering ECU stores this DTC when it determines that the assist map is not written in the ECU.

HINT:

The assist map is data written in the power steering ECU to control the degree of assistance. The assist map is selected based on the vehicle's specified communication data.

DTC No.

DTC Detection Condition

Trouble Area

C1581

Assist map not written in power steering ECU

  • Power steering ECU
  • CAN communication system
  • ECM
  • Brake actuator assembly (Skid control ECU)
PROCEDURE
  1. INITIALIZE ROTATION ANGLE SENSOR AND CALIBRATE TORQUE SENSOR ZERO POINT

(a) Initialize the rotation angle sensor value and calibrate the torque sensor zero point (See page ).


HINT:

The assist map is automatically written during the rotation angle sensor initialization and torque sensor zero point calibration.

NEXT
  1. CHECK FOR DTC

(a) Check for DTCs (See page ).


OK:

DTC C1581 is not output.

HINT:

DTC C1581 will be cleared after the assist map is written.


OK

END

NG
  1. CHECK FOR DTC (CAN COMMUNICATION SYSTEM)

(a) Using the Techstream, check for DTCs and confirm that there are no problems in the CAN communication system (See page ).


OK:

DTC is not output.


NG

GO TO CAN COMMUNICATION SYSTEM

OK
  1. CHECK ECM

(a) Check if an ECM that complies with the vehicle specifications is installed.

OK:

ECM that complies with vehicle specifications is installed.

Result

Result

Proceed to

OK

A

NG (for 2GR-FE)

B

NG (for 1AR-FE)

C


B

REPLACE ECM


C

REPLACE ECM

A
  1. CHECK BRAKE ACTUATOR ASSEMBLY

(a) Check if a brake actuator assembly (skid control ECU) that complies with the vehicle specifications is installed.

OK:

Brake actuator assembly (skid control ECU) that complies with vehicle specifications is installed.


OK

REPLACE POWER STEERING ECU


NG

REPLACE BRAKE ACTUATOR ASSEMBLY

Test yourself

A quick Toyota Venza quiz: every answer comes with an explanation and a link to the manual page.