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 control ECU assembly to illuminate the stop lights.

  If the power management control ECU receives a stop light control ECU assembly 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 power management control ECU. When the power management 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 power management control ECU through the STOP fuse and stop light switch assembly, and the power management control ECU turns the dynamic radar cruise control system off.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1. CHECK FOR DTCs (PRE-COLLISION SYSTEM)

   
   

   1. Check for DTCs of the pre-collision 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-collision system. Therefore, if DTC P0571 is stored, inspect the pre-collision system first.

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

   
   

   A

   GO TO PRE-COLLISION 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 A74 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 A74-3 (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 A74-1 (B) - Body ground Always 11 to 14 V A74-5 (B) - Body ground Power switch on (IG) 11 to 14 V A74-5 (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 (POWER MANAGEMENT CONTROL ECU - STOP LIGHT SWITCH ASSEMBLY)

   
   

   1. Disconnect the A20 power management control ECU connector.

   2. Disconnect the A74 stop light switch assembly connector.

   3. Disconnect the A61 skid control ECU (brake booster with master cylinder assembly) connector.

   4. Disconnect the A27 stop light control ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition A20-7 (ST1-) - A74-4 (L) Always Below 1 Ω A20-23 (STP) - A74-2 (L) Always Below 1 Ω A20-7 (ST1-) or A74-4 (L) - Body ground Always 10 kΩ or higher A20-23 (STP) or A74-2 (L) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE POWER MANAGEMENT CONTROL ECU Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR