HILL LAUNCH ASSIST (HLA) OPERATES EVEN ON DOWNHILL SLOPE/HILL LAUNCH ASSIST (HLA) DOES NOT OPERATE EVEN ON UPHILL SLOPE [ELECTRONICALLY CONTROLLED BRAKE SYSTEM]

id040309070900

Outline

Description	Hill Launch Assist (HLA) operates even on downhill slope Hill Launch Assist (HLA) does not operate even on uphill slope
Possible cause	Note •  The Hill Launch Assist (HLA) operates on an uphill slope of approx. 5% or more when in a position other than R. •  The Hill Launch Assist (HLA) operates on a downhill slope of approx. 5% or more when in a position other than R. •  The Hill Launch Assist (HLA) operates for a maximum 2 s after the brake pedal is released. •  Electronically controlled brake unit detects malfunction (input/output device malfunction) •  PCM and instrument cluster detect malfunction •  Sophisticated Airbag Sensor (SAS) control module installation malfunction (if there is Sophisticated Airbag Sensor (SAS) control module installation malfunction, Hill Launch Assist (HLA) may not operate at desired inclination angle) •  Tire malfunction (4 tires with air pressure or wear condition that differ are used) •  Electronically controlled brake unit related parts sensor initialization procedure not performed after replacing electronically controlled brake unit and Sophisticated Airbag Sensor (SAS) control module (if sensor initialization procedure for electronically controlled brake unit related parts is not performed, Hill Launch Assist (HLA) may not operate at desired inclination angle) •  Center point of low-G sensor is deviated •  ABS wheel-speed sensor outputs error signal •  Input signal error from PCM (accelerator pedal position signal) •  Input signal error from selector lever (selector lever position signal) •  Communication error between electronically controlled brake unit and PCM •  Communication error between electronically controlled brake unit and body control module (BCM) •  Communication error between body control module (BCM) and instrument cluster •  Brake (brake pedal, parking brake) drag
System wiring diagram	Not applicable
Connector diagram	Not applicable

Diagnostic Procedure

Step	Inspection	Results	Action
1	INSPECT RELATED MODULE FOR MALFUNCTION •  Perform the DTC inspection for the electronically controlled brake unit, PCM, selector lever, and the instrument cluster. (See DTC INSPECTION.) •  Is a DTC displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [ELECTRONICALLY CONTROLLED BRAKE UNIT].) (See DTC TABLE [PCM (e-SKYACTIV)].) (See DTC TABLE [SELECTOR LEVER])
		No	Go to the next step.
2	VERIFY SOPHISTICATED AIRBAG SENSOR (SAS) CONTROL MODULE INSTALLATION CONDITION •  Verify the Sophisticated Airbag Sensor (SAS) control module installation condition. •  Is Sophisticated Airbag Sensor (SAS) control module (yaw rate sensor, low-G sensor) securely installed?	Yes	Go to the next step.
		No	Install the Sophisticated Airbag Sensor (SAS) control module securely, and perform the repair completion verification. (See SAS CONTROL MODULE REMOVAL/INSTALLATION [TWO-STEP DEPLOYMENT CONTROL SYSTEM (E)].)
3	VERIFY SENSOR INITIALIZATION PROCEDURE PERFORMANCE CONDITION FOR ELECTRONICALLY CONTROLLED BRAKE UNIT RELATED PARTS •  After replacing the electronically controlled brake unit and the Sophisticated Airbag Sensor (SAS) control module, has the sensor initialization procedure for the electronically controlled brake unit related parts been performed?	Yes	Go to the next step.
		No	Perform the sensor initialization procedure for the electronically controlled brake unit related parts, and perform the repair completion verification. (See ELECTRONICALLY CONTROLLED BRAKE UNIT RELATED PARTS SENSOR INITIALIZATION PROCEDURE.)
4	VERIFY TIRE CONDITION •  Verify the tire pressure and wear condition of the tire. (See WHEEL AND TIRE SPECIFICATION [(E)].) •  Are the tire pressure and wear condition of the tire normal?	Yes	Go to the next step.
		No	If the tire pressure is incorrect, adjust it to the specification. If the tire is worn, replace the tire. Perform the repair completion verification.
5	INSPECT SIGNAL OF RELATED MODULE FOR MALFUNCTION •  Verify the following electronically controlled brake unit, PCM, and selector lever PIDs. (See PID/DATA MONITOR INSPECTION.) Electronically controlled brake unit ―  BRK_PEDAL_SW (brake switch signal) ―  ACC_LON_C (longitudinal acceleration speed signal (calculated value)) ―  ACC_LON_C (longitudinal acceleration speed signal (calculated value)) ―  BRK_FLD_PRES (brake fluid pressure signal (raw value)) ―  WSPD_SEN_L/F (ABS wheel-speed sensor (LF) signal) ―  WSPD_SEN_R/F (ABS wheel-speed sensor (RF) signal) ―  WSPD_SEN_L/R (ABS wheel-speed sensor (LR) signal) ―  WSPD_SEN_R/R (ABS wheel-speed sensor (RR) signal) PCM ―  APP1 (APP sensor signal) Selector lever ―  SELECTOR_LEVER_POS •  Are all PID values normal?	Yes	Inspect the following. •  Brake (brake pedal, parking brake) drag Repair or replace the malfunctioning location according to the inspection results. Perform the repair completion verification.
		No	Inspect the related parts and wiring harnesses. Repair or replace the malfunctioning location according to the inspection results. Perform the repair completion verification.
Repair completion verification	VERIFY IF MALFUNCTION CAUSE IS CORRECTED •  Install/connect the part removed/disconnected during the troubleshooting procedure. •  Has the malfunction symptom been eliminated?	Yes	Complete the symptom troubleshooting. Explain repair contents to customer.
		No	Refer to the CAN (controller area network) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [L.H.D. (E)].) (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [R.H.D.].) If the CAN communication is normal, perform the diagnosis from Step 1.