NO.37 VEHICLE MOVES WHEN ACCELERATING FROM STANDSTILL ON SLOPE [SKYACTIV-G 2.0]

id0103e6103100

37

VEHICLE MOVES WHEN ACCELERATING FROM STANDSTILL ON SLOPE
DESCRIPTION
•  Vehicle slips backwards on inclined road surface when accelerating after i-stop operates.
POSSIBLE CAUSE
Note
•  i-stop (engine-stop control) continues operating when shifting the selector lever from D position to N or P position while i-stop (engine-stop control) is operating, however, if the slope of the road surface is within ±4 %, the Hill Launch Assist (HLA) function is canceled.
Hill launch assist function system (DSC) malfunction
•  False detection of inclination angle (cannot calculate correct road slope)
―  Low-G (XY) sensor (built-into SAS control module) malfunction (In this case, the SAS control module records DTCs C1280, C1282 and C2770.)
―  Low-G (XY) sensor (built-into SAS control module) initialization malfunction (In this case, the SAS control module records DTC B2477.)
•  False detection of brake fluid pressure
―  Brake fluid pressure sensor (built-into DSC HU/CM) malfunction
•  Cannot maintain brake fluid pressure
―  DSC HU/CM malfunction
•  DC-DC converter system error (exceeds capacity of DC-DC converter output due to open or short circuit in wiring harness and after-market electrical part)
ATX system malfunction
•  Electric AT oil pump malfunction (operation malfunction, insufficient pressure)
•  ATX malfunction

Diagnostic Procedure

STEP

INSPECTION

RESULTS

ACTION
1
INSPECT EFFECT OF NON-GENUINE ELECTRICAL ACCESSORY FOR CAUSE OF MALFUNCTION
•  Remove any non-genuine electrical accessory.
•  Verify the malfunction symptom.
•  Does vehicle slip backwards on inclined road surface when accelerating after i-stop operates?
Yes
The system is normal.
•  Explain to the customer that the vehicle slips backwards on an inclined road surface when accelerating after i-stop operates due to the effect of the non-genuine electrical accessory installed.
No
Go to the next step.
2
VERIFY DTC
•  Retrieve the PCM, TCM, DSC HU/CM, SAS control module DTCs using the M-MDS.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [SKYACTIV-G 2.0].)
(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [FW6A-EL].)
(See ON-BOARD DIAGNOSIS [DYNAMIC STABILITY CONTROL (DSC)].)
(See DTC TABLE.)
No
Go to the next step.
3
DETERMINE IF MALFUNCTION CAUSE IS HILL LAUNCH ASSIST FUNCTION OR ATX SYSTEM
•  Verify the malfunction symptom on a flat road surface.
•  Does the acceleration lag when accelerating?
Yes
Perform the symptom troubleshooting “NO.36 ACCELERATION MALFUNCTION”.
(See NO.36 ACCELERATION MALFUNCTION [SKYACTIV-G 2.0].)
No
Brake fluid pressure sensor (built-into DSC HU/CM) or DSC HU/CM brake pressure hold function malfunction.
•  Replace the DSC HU/CM.
4
Verify the test results.
•  If normal, return to the diagnostic index to service any additional symptoms.
•  If a malfunction remains, inspect the related Service Information and perform the repair or diagnosis.
―  If the vehicle is repaired, troubleshooting is completed.
―  If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM.