Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM1000000026PVW
Model Year Start: 2023 Model: Corolla HV Prod Date Range: [09/2022 -           ]
Title: HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): P05042B; Brake Switch "A"/"B" Signal Cross Coupled; 2023 - 2025 MY Corolla HV [09/2022 -        ]

DTC

P05042B

Brake Switch "A"/"B" Signal Cross Coupled

DESCRIPTION

The stop light switch assembly is a duplex system that transmits two signals: STP and ST1-. These two signals are used by the hybrid vehicle control ECU to monitor whether or not the brake system is working properly. If the signals, which indicate the brake pedal is being depressed and released, are detected simultaneously, the hybrid vehicle control ECU interprets this as a malfunction in the stop light switch assembly and stores this DTC.

HINT:

The normal signal conditions are as shown in the table below.

Signal (hybrid vehicle control ECU Terminal)

Brake Pedal Released

In Transition

Brake Pedal Depressed

STP

OFF

ON

ON

ST1-

ON

ON

OFF

  • [OFF] denotes ground potential.
  • [ON] denotes auxiliary battery potential (+B).

On the GTS, Data List item Stop Light SW is ON when the brake pedal is depressed.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

Note

P05042B

Brake Switch "A"/"B" Signal Cross Coupled

Conditions (a) and (b) are met for 0.5 seconds or more (1 trip detection logic):

(a) Ignition switch ON

(b) STP signal OFF when ST1- signal OFF

  • Wire harness or connector
  • Stop light switch assembly
  • Hybrid vehicle control ECU

Does not come on

Master Warning:

Does not come on

SAE Code:

P0504

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

HINT:

  • Stop light switch assembly conditions can be checked using the GTS.
    1. Enter the following menus: Powertrain / Hybrid Control / Data List / Stop Light SW.
    2. Check the Data List indication when the brake pedal is depressed and released.

      Brake Pedal Operation

      Stop Light SW

      Depressed

      ON

      Released

      OFF

  • Read Freeze Frame Data using the GTS. The ECM records vehicle and driving condition information as Freeze Frame Data the moment a DTC is stored. When troubleshooting, Freeze Frame Data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.

CHECK TERMINAL VOLTAGE (POWER SOURCE OF STOP LIGHT SWITCH ASSEMBLY)

(a) Disconnect the stop light switch assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A53-7 (B) - Body ground

Always

11 to 14 V

(c) Reconnect the stop light switch assembly connector.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

2.

CHECK TERMINAL VOLTAGE (POWER SOURCE OF STOP LIGHT SWITCH ASSEMBLY)

(a) Disconnect the stop light switch assembly connector.

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A53-6 (B) - Body ground

Ignition switch ON

11 to 14 V

(d) Turn the ignition switch off.

(e) Reconnect the stop light switch assembly connector.

NG

GO TO STEP 6

OK

3.

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BODY GROUND)

(a) Disconnect the stop light switch assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A53-2 (GND) - Body ground

Always

Below 1 Ω

(c) Reconnect the stop light switch assembly connector.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

CHECK TERMINAL VOLTAGE (STP AND ST1- VOLTAGE)

(a) Disconnect the hybrid vehicle control ECU connector.

(b) Turn the ignition switch to ON.

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

*a

Brake Pedal Depressed

*b

Brake Pedal Released

*c

Front view of wire harness connector

(to Hybrid Vehicle Control ECU)

-

-

Standard Voltage:

Tester Connection

Brake Pedal Operation

Specified Condition

A161-7 (ST1-) - Body ground

Released

7.5 to 14 V

Depressed

Below 1.5 V

A161-22 (STP) - Body ground

Released

Below 1.5 V

Depressed

7.5 to 14 V

(d) Turn the ignition switch off.

(e) Reconnect the hybrid vehicle control ECU connector.

OK

REPLACE HYBRID VEHICLE CONTROL ECU

NG

5.

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - HYBRID VEHICLE CONTROL ECU)

(a) Disconnect the stop light switch assembly connector.

(b) Disconnect the hybrid vehicle control ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A161-7 (ST1-) - A53-5 (L)

Always

Below 1 Ω

A161-22 (STP) - A53-3 (L)

Always

Below 1 Ω

A161-7 (ST1-) or A53-5 (L) - Body ground and other terminals

Always

10 kΩ or higher

A161-22 (STP) or A53-3 (L) - Body ground and other terminals

Always

10 kΩ or higher

(d) Reconnect the hybrid vehicle control ECU connector.

(e) Reconnect the stop light switch assembly connector.

OK

REPLACE STOP LIGHT SWITCH ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.

CHECK HARNESS AND CONNECTOR (IGP-MAIN RELAY - STOP LIGHT SWITCH ASSEMBLY)

(a) Remove the IGP-MAIN relay from the No. 1 engine room relay block and No. 1 junction block assembly.

(b) Disconnect the stop light switch assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 (IGP-MAIN relay holder) - A53-6 (B)

Always

Below 1 Ω

3 (IGP-MAIN relay holder) or A53-6 (B) - Body ground and other terminals

Always

10 kΩ or higher

(d) Reconnect the stop light switch assembly connector.

(e) Install the IGP-MAIN relay.

OK

CHECK ECU POWER SOURCE CIRCUIT

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR