DYNAMIC RADAR CRUISE CONTROL SYSTEM, Diagnostic DTC:P0571

DESCRIPTION

Condition 1:

• When the brakes are applied by the dynamic radar cruise control system, the skid control ECU (brake booster with master cylinder assembly) operates the stop light switch assembly (stop light control relay) to illuminate the stop lights.

  If the hybrid vehicle control ECU receives a stop light control relay malfunction signal from the skid control ECU (brake booster with master cylinder assembly), DTC P0571 is stored.

Condition 2:

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

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1. CHECK FOR DTCs (PRE-CRASH SAFETY SYSTEM)

   
   

   1. Check for DTCs of the pre-crash safety system.

      Click here

      Tech Tips

      When DTC P0571 is stored by the dynamic radar cruise control system, DTC C1A4B may be stored by the pre-crash safety system. Therefore, if DTC P0571 is stored, inspect the pre-crash safety system first.

      Result
      Result Proceed to DTC C1A4B is output A DTC C1A4B is not output B

   
   

   A

   GO TO PRE-CRASH SAFETY SYSTEM Click here

   B

2. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - AUXILIARY BATTERY AND BODY GROUND)

   
   
   1. 

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

      Disconnect the A79 stop light switch assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition A79-2 (GND) - Body ground Always Below 1 Ω

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

      Standard Voltage
      Tester Connection Condition Specified Condition A79-7 (B) - Body ground Always 11 to 14 V A79-6 (B) - Body ground Power switch on (IG) 11 to 14 V A79-6 (B) - Body ground Power switch off Below 1 V

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

3. INSPECT STOP LIGHT SWITCH ASSEMBLY

   
   

   1. Inspect the stop light switch assembly.

      Click here

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

   OK

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

   
   

   1. Disconnect the A21 and A22 hybrid vehicle control ECU connector.

   2. Disconnect the A79 stop light switch assembly connector.

   3. Disconnect the A58 skid control ECU (brake booster with master cylinder assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition A22-28 (ST1-) - A79-5 (L) Always Below 1 Ω A21-15 (STP) - A79-3 (L) Always Below 1 Ω A22-28 (ST1-) or A79-5 (L) - Body ground Always 10 kΩ or higher A21-15 (STP) or A79-3 (L) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE HYBRID VEHICLE CONTROL ECU Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR