DYNAMIC RADAR CRUISE CONTROL SYSTEM(for 2AR-FE), Diagnostic DTC:P0571

DESCRIPTION

Condition 1:

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

  If the ECM receives a stop light control relay malfunction signal from the skid control ECU (brake actuator assembly), DTC P0571 is stored.

Condition 2:

• When the brake pedal is depressed, the stop light switch assembly sends a signal to the ECM. When the ECM 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 ECM through the STOP fuse and the stop light switch assembly, and the ECM 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.

      
      Body Electrical > Pre-Collision 2 > Trouble Codes

      Tech Tips

      When DTC P0571 is stored by the dynamic radar cruise control system, DTC C1A4B is 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 - BATTERY AND BODY GROUND)

   
   
   1. 

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

      Disconnect the A37 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 A37-2 (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 A37-7 (B) - Body ground Always 11 to 14 V A37-6 (B) - Body ground Engine switch on (IG) 11 to 14 V A37-6 (B) - Body ground Engine 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 (ECM - STOP LIGHT SWITCH ASSEMBLY)

   
   

   1. Disconnect the A22 ECM connector.

   2. Disconnect the A37 stop light switch assembly connector.

   3. Disconnect the A34 skid control ECU (brake actuator assembly) connector.

   4. Disconnect the R8 certification ECU (smart key ECU assembly) connector.

   5. Disconnect the K27 shift lock control ECU (shift lock control unit assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition A22-10 (ST1-) - A37-5 (L) Always Below 1 Ω A22-9 (STP) - A37-3 (L) Always Below 1 Ω A22-10 (ST1-) or A37-5 (L) - Body ground Always 10 kΩ or higher A22-9 (STP) or A37-3 (L) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE ECM Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR