ACTIVE HEIGHT CONTROL SUSPENSION, Diagnostic DTC:C1715, C1716, C1717, C1796, C1797, C1798

DESCRIPTION

The acceleration sensor (up and down G sensor) detects the upward and downward acceleration of the vehicle, and outputs it as a voltage to the suspension control ECU. Up and down G sensors are installed in 3 locations: 1) the suspension control ECU, 2) the driver side instrument panel, and 3) the passenger side instrument panel. Each up and down G sensor independently detects the upward and downward acceleration. During a test mode inspection, the suspension control ECU reads the fluctuations in the signal of each sensor. When the sensor cannot detect +/-1.96 m/s²for 1 second or more during test mode, DTCs C1796, C1797 and C1798 are stored.

WIRING DIAGRAM

*a	SGG
*b	Front Acceleration Sensor LH
*c	Front Acceleration Sensor RH
*d	Suspension Control ECU (Houses Rear Acceleration Sensor)

CAUTION / NOTICE / HINT

PROCEDURE

1. CHECK ACCELERATION SENSOR (DATA LIST)

   
   

   1. Turn the engine switch off.

   2. Connect the intelligent tester to the DLC3.

   3. Turn the engine switch on (IG) and the tester on.

   4. Enter the following menus: Chassis / AHC / Data List.

   5. According to the display on the tester, read the Data List.

      AHC

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      (Up & Down)G Sensor FR	G (up and down) front acceleration sensor RH reading/ min.: -1045.29 m/s2 max.: 1045.26 m/s2	0 +/-0.98 m/s2at still condition	Reading changes when vehicle (FR) is bounced
      (Up & Down)G Sensor FL	G (up and down) front acceleration sensor LH reading/ min.: -1045.29 m/s2 max.: 1045.26 m/s2	0 +/-0.98 m/s2at still condition	Reading changes when vehicle (FL) is bounced
      (Up & Down)G Sensor Rear	G (up and down) rear acceleration sensor reading/ min.: -1045.29 m/s2 max.: 1045.26 m/s2	0 +/-0.98 m/s2at still condition	Reading changes when vehicle (rear) is bounced

      OK
      Reading changes when vehicle is bounced.

   
   

   NG

   CHECK HARNESS AND CONNECTOR (ACCELERATION SENSOR - SUSPENSION CONTROL ECU) Click here

   OK

2. RECONFIRM DTC OUTPUT

   
   

   1. Clear the DTCs Click here.

   2. Perform a road test.

   3. Check for DTCs.

      Result

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

   
   

   B

   USE SIMULATION METHOD TO CHECK Click here

   A

3. CHECK HARNESS AND CONNECTOR (ACCELERATION SENSOR - SUSPENSION CONTROL ECU)

   Note

   When inspecting the wire harnesses between the suspension control ECU and acceleration sensors, it is difficult to determine the malfunctioning area if there is a sensor power supply malfunction. Therefore, disconnect the connectors for the acceleration sensors (front RH, front LH), the fluid temperature sensor, and fluid pressure sensor on the ECU side.

   
   

   1. Check the front acceleration sensor RH side: (C1715)

      

      *1	Rear view of wire harness connector: (to Suspension Control ECU)
      *2	Front view of wire harness connector: (to Front Acceleration Sensor RH)
      *3	SGG

      
      

      1. Disconnect the K34 and K35 ECU connectors.

      2. Disconnect the L35 sensor connector.

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

         Standard Resistance
         Tester Connection Condition Specified Condition L35-1 (SGFR) - K34-24 (SGFR) Always Below 1 Ω L35-2 (SGG) - K34-14 (SGG1) Always Below 1 Ω L35-3 (SGB) - K34-15 (SGB1) Always Below 1 Ω K34-24 (SGFR) - Body ground Always 10 kΩ or higher K34-14 (SGG1) - Body ground Always 10 kΩ or higher K34-15 (SGB1) - Body ground Always 10 kΩ or higher

   2. Check the front acceleration sensor LH side: (C1716)

      
      

      1. Disconnect the K34 and K35 ECU connectors.

      2. Disconnect the K37 sensor connector.

         

         *1	Rear view of wire harness connector: (to Suspension Control ECU)
         *2	Front view of wire harness connector: (to Front Acceleration Sensor LH)
         *3	SGG

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

         Standard Resistance
         Tester Connection Condition Specified Condition K37-1 (SGFL) - K34-22 (SGFL) Always Below 1 Ω K37-2 (SGG) - K34-13 (SGG2) Always Below 1 Ω K37-3 (SGB) - K34-23 (SGB2) Always Below 1 Ω K34-22 (SGFL) - Body ground Always 10 kΩ or higher K34-13 (SGG2) - Body ground Always 10 kΩ or higher K34-23 (SGB2) - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

4. INSPECT ACCELERATION SENSOR

   

   
   

   1. Turn the engine switch off.

   2. Remove the front acceleration sensor Click here.

      Note

      Do not drop the acceleration sensor. If it is dropped, replace it with a new one.

   3. Connect 3 1.5 V dry cell batteries in series.

   4. Connect the positive (+) end of the batteries to terminal 3 (SGB) of the acceleration sensor and the negative (-) end of the batteries to terminal 2 (SGG). Then measure the voltage between terminal 1 (SGFR*1, SGFL*2) and terminal 2 (SGG).

      Tech Tips

      *1: for RH

      *2: for LH

      Note

      Do not apply a voltage of more than 6 V.

      Tech Tips

      The voltage may differ according to the amount that the sensor is tilted.

      Standard Voltage
      for RH Tester Connection Condition Specified Condition 1 (SGFR) - 2 (SGG) Sensor stationary Approx. 2.0 to 2.5 V Sensor is tilted Change between approx. 0.9 to 2.3 V
      for LH Tester Connection Condition Specified Condition 1 (SGFL) - 2 (SGG) Sensor stationary Approx. 2.0 to 2.5 V Sensor is tilted Change between approx. 0.9 to 2.3 V

   
   

   OK

   REPLACE SUSPENSION CONTROL ECU Click here

   NG

   REPLACE ACCELERATION SENSOR Click here