Last Modified: 06-05-2026 6.11:8.1.0 Doc ID: RM100000001C0X9
Model Year Start: 2019 Model: Corolla Prod Date Range: [06/2018 - 09/2019]
Title: POWER ASSIST SYSTEMS: POWER STEERING SYSTEM (for Gasoline Model (for Hatchback)): C1552,C1554; PIG Power Supply Voltage; 2019 - 2020 MY Corolla Corolla Hatchback [06/2018 - 09/2019]

DTC

C1552

PIG Power Supply Voltage

DTC

C1554

Power Supply Relay Failure

DESCRIPTION

If a problem occurs in the system, the power source relay circuit and the motor relay circuit are shut off to stop power assist. The ECU must be replaced when there is a problem with the relays because the relays are built into the ECU.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

Return-to-normal Condition

Note

C1552

PIG Power Supply Voltage

PIG power source circuit malfunction
  • EPS fuse
  • PIG power source circuit
  • Power steering ECU with motor assembly

EPS warning light: Comes on

Engine switch on (IG) again

-

C1554

Power Supply Relay Failure

Power source relay circuit malfunction
  • EPS fuse
  • PIG power source circuit
  • Power steering ECU with motor assembly

EPS warning light: Comes on

Engine switch on (IG) again

-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • If the power steering ECU with motor assembly has been replaced, perform assist map writing and torque sensor zero point calibration.

    Click here 2019 - 2020 MY Corolla Corolla Hatchback [06/2018 - 09/2019]; POWER ASSIST SYSTEMS: POWER STEERING SYSTEM (for Gasoline Model (for Hatchback)): CALIBRATION

  • Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (POWER STEERING ECU WITH MOTOR ASSEMBLY - BODY GROUND)

(a) Disconnect the I42 power steering ECU with motor assembly connectors.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection

Condition

Specified Condition

I42-1 (PIG) - Body ground

Always

9 to 16 V

*a

Front view of wire harness connector

(to Power Steering ECU with Motor Assembly)

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection

Condition

Specified Condition

I42-2 (PGND) - Body ground

Always

Below 1 Ω
OK

REPLACE POWER STEERING ECU WITH MOTOR ASSEMBLY

Click here 2019 MY Corolla Hatchback [06/2018 - 01/2019]; POWER ASSIST SYSTEMS: POWER STEERING ECU: REMOVAL 2020 MY Corolla Corolla Hatchback Corolla HV [01/2019 - 03/2019]; POWER ASSIST SYSTEMS: POWER STEERING ECU: REMOVAL 2020 MY Corolla Corolla Hatchback Corolla HV [03/2019 - 09/2019]; POWER ASSIST SYSTEMS: POWER STEERING ECU: REMOVAL

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR