CRUISE CONTROL SYSTEM, Diagnostic DTC:P0571

DESCRIPTION

When the brake pedal is depressed, the stop light switch assembly sends a signal to the power management control ECU. When the power management control ECU receives this signal, it cancels the cruise control. The fail-safe function operates to enable normal driving even if there is a malfunction in the stop light signal circuit. Cruise control cancellation occurs when voltage is applied to terminal STP. When the brake is applied, voltage is normally applied to terminal STP of the power management control ECU through the STOP fuse and the stop light switch assembly, and the power management control ECU turns the cruise control off.

INSPECTION PROCEDURE

PROCEDURE

1. Click here

   INSPECT STOP LIGHT SWITCH ASSEMBLY (POWER SOURCE)

   
   
   1. 

      Disconnect the stop light switch assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition A25-2 - Body ground Always 11 to 14 V

      Table 1. Text in Illustration

      *a	Front view of wire harness connector (to Stop Light Switch Assembly)

   3. Reconnect the stop light switch assembly connector.

   
   
   • OKClick here
   • NGClick here
2. Click here

   INSPECT STOP LIGHT SWITCH ASSEMBLY (POWER SOURCE)

   
   
   1. 

      Disconnect the stop light switch assembly connector.

   2. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition A25-4 - Body ground Power switch on (IG) 11 to 14 V

      Table 2. Text in Illustration

      *a	Front view of wire harness connector (to Stop Light Switch Assembly)

   4. Reconnect the stop light switch assembly connector.

   
   
   • OKClick here
   • NGClick here
3. Click here

   INSPECT STOP LIGHT SWITCH ASSEMBLY

   
   
   1. 

      Remove the stop light switch assembly (Click here).

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition 1 - 2 Switch pin not pushed Below 1 Ω 3 - 4 Switch pin not pushed 10 kΩ or higher 1 - 2 Switch pin pushed 10 kΩ or higher 3 - 4 Switch pin pushed Below 1 Ω

      Table 3. Text in Illustration

      *a	Component without harness connected (Stop Light Switch Assembly)
      *b	Not pushed
      *c	Pushed

   3. Reinstall the stop light switch assembly (Click here).

   
   
   • OKClick here
   • NGClick here
4. Click here

   CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - STOP LIGHT SWITCH ASSEMBLY)

   
   

   1. Disconnect the power management control ECU connector.

   2. Disconnect the stop light switch assembly connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition A20-23 (STP) - A25-1 Always Below 1 Ω A20-7 (ST1-) - A25-3 Always Below 1 Ω

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition A20-23 (STP) or A25-1 - Body ground Always 10 kΩ or higher A20-7 (ST1-) or A25-3 - Body ground Always 10 kΩ or higher

   4. Reconnect the stop light switch assembly connector.

   5. Reconnect the power management control ECU connector.

   
   
   • OKClick here
   • NGClick here
5. Click here

   REPLACE POWER MANAGEMENT CONTROL ECUClick here

6. Click here

   REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER MANAGEMENT CONTROL ECU - STOP LIGHT SWITCH ASSEMBLY)

7. Click here

   REPLACE STOP LIGHT SWITCH ASSEMBLYClick here

8. Click here

   REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - IG2 RELAY)

9. Click here

   REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BATTERY)