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Home >> Acura >> 2017 >> MDX Base >> Repair and Diagnosis (Single Page) >> Transmission >> Automatic Trans >> Automatic Transaxle - Service, Testing And Troubleshooting (Except Hybrid) >> Symptom Troubleshooting Index >> A/T System Symptom Troubleshooting Index (2016 2017 2018 2019 2020)
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A/T System Symptom Troubleshooting Index (2016 2017 2018 2019 2020)

NOTE: Do an all DTC check with the HDS, and troubleshoot any DTCs first before following the repair procedures listed in the index.
Symptom Probable cause(s) Notes
When the vehicle ON mode, the A/T gear position indicator displays an improper position, or it never displays at all
  • F-CAN communication line error
  • Gauge control module defective
  • TCM defective
  • SBW shifter assembly defective
A/T gear position indicator does not indicate the same position as the SBW shifter
  • F-CAN communication line error
  • Gauge control module defective
  • PCM defective
  • SBW shifter assembly defective
Shift indicator does not work
  • F-CAN communication line error
  • TCM defective
  • SBW shifter assembly defective
When you press the paddle shifter, the transmission does not upshift/downshift Troubleshoot the paddle shifter circuit .
The paddle shifter illumination does not come on when the combination light switch is turned on Paddle shifter illumination circuit Troubleshoot the paddle shifter illumination circuit .
SBW shifter cannot be changed from P position/mode while pressing on the brake pedal
  • F-CAN communication line error
  • Brake pedal position switch circuit
  • Brake pedal position switch defective
  • Accelerator pedal position sensor circuit
  • Accelerator pedal position sensor defective
  • Relative throttle position sensor value too high
  • Throttle body defective
  • SBW shifter assembly defective
Symptom Probable cause(s) Notes
M indicator does not come on even though the paddle shifter is operated in sequential shift mode
  • F-CAN communication line error
  • Gauge control module defective
  • SBW shifter assembly defective
  • Paddle shifter defective
HDS does not communicate with the TCM
  • F-CAN communication line error
  • TCM defective
Check the F-CAN communication line - Refer to: F-CAN Circuit Troubleshooting(Without CAN Gateway) (2016), or F-CAN Circuit Troubleshooting (2014 2015), or F-CAN Circuit Troubleshooting (2017 2018) .
Engine runs, but vehicle does not move in any positions/modes
  • TCM defective
  • Stuck in park mechanism
  • Drive plate defective or transmission incorrectly installed
  • Axle disengaged
  • Check for an incorrectly installed transmission, and check the drive plate for wear and damage. Replace the drive plate if it is worn or damaged.
  • Check the axles.
Poor acceleration; engine revs up abnormally high when starting off
  • TCM defective
  • Drive plate defective or transmission incorrectly installed
  • Torque converter defective
Engine idle vibration
  • Engine output low
  • Drive plate defective or transmission incorrectly installed
  • Torque converter clutch defective
  • Transmission or engine mount defective
  • Check the stall speed - Refer to: Stall Speed Test (2016),  or Stall Speed Test (2014 2015) .
  • Check for an incorrectly installed transmission, and check the drive plate for wear and damage. Replace the drive plate if it is worn or damaged.
  • Inspect the transmission or engine mount.
Vehicle moves in N
  • Low ATF level
  • Excessive ATF
  • Hydraulic control unit defective
Delayed engagement after shifting, or excessive shock when shifting
  • Low ATF level
  • Hydraulic control unit defective
  • Torque converter defective
  • Clutch clearance incorrect
Transmission does not shift
  • F-CAN communication line error
  • Low ATF level
  • TCM defective
  • Wrong tires
Excessive shock or engine revs up abnormally high on any upshift or downshift
  • Low ATF level
  • TCM defective
  • Engine torque or speed failure
  • Hydraulic pressure characteristic calibration not complete
Symptom Probable cause(s) Notes
Engine stalls at still stand
  • Hydraulic control unit defective
  • Drive plate defective or transmission incorrectly installed
  • Torque converter defective
  • Low ATF temperature
Engine does not start
  • No engine start signal
  • SBW shifter assembly defective
Check for a poor connection at the SBW shifter assembly.
Engine stalls when shifted to N position/mode from D position/mode
  • Hydraulic control unit defective
  • Torque converter defective
Engine stalls when shifted to N position/mode from R position/mode
  • Hydraulic control unit defective
  • Torque converter defective
No engine braking Check the F-CAN communication line - Refer to: F-CAN Circuit Troubleshooting(Without CAN Gateway) (2016), or F-CAN Circuit Troubleshooting (2014 2015), or F-CAN Circuit Troubleshooting (2017 2018) .
Noise from transmission in any positions/modes
  • ATF pump or pump chain defective
  • Hydraulic control unit defective
  • Drive plate defective or transmission incorrectly installed
  • Internal transmission bearing damaged
  • Replace the hydraulic control unit .
  • Check for an incorrectly installed transmission, and check the drive plate for wear and damage. Replace the drive plate if it is worn or damaged.
Transmission does not shift into P position/mode Park mechanism defective