A/T System Symptom Troubleshooting Index (2016 2017 2018: 9-Speed A/T)

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	Check the F-CAN communication line - Refer to: F-CAN Circuit Troubleshooting (2016 2017 2018: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2016 2017 2018: 6-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020 2021: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020: 6-Speed A/T) . Check the F-CAN communication line by using the gauge control module self-diagnostic function - Refer to: Gauges Self-Diagnostic Function (2019 2020 2021) or Gauges Self-Diagnostic Function (2016 2017 2018) . Check the indicator drive circuit in the gauge control module by using the gauge control module self-diagnostic function - Refer to: Gauges Self-Diagnostic Function (2019 2020 2021) or Gauges Self-Diagnostic Function (2016 2017 2018) . Check for a poor connection at the SBW shifter assembly.
A/T gear position indicator does not indicate the same position as the SBW shifter	F-CAN communication line error Gauge control module defective TCM defective SBW shifter assembly defective	Check the F-CAN communication line - Refer to: F-CAN Circuit Troubleshooting (2016 2017 2018: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2016 2017 2018: 6-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020 2021: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020: 6-Speed A/T) . Check the F-CAN communication line by using the gauge control module self-diagnostic function - Refer to: Gauges Self-Diagnostic Function (2019 2020 2021) or Gauges Self-Diagnostic Function (2016 2017 2018) . Check the indicator drive circuit in the gauge control module by using the gauge control module self-diagnostic function - Refer to: Gauges Self-Diagnostic Function (2019 2020 2021) or Gauges Self-Diagnostic Function (2016 2017 2018) . Check for a poor connection at the SBW shifter assembly.
Shift indicator does not work	F-CAN communication line error TCM defective Gauge control module defective	Check the F-CAN communication line - Refer to: F-CAN Circuit Troubleshooting (2016 2017 2018: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2016 2017 2018: 6-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020 2021: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020: 6-Speed A/T) . Check the F-CAN communication line by using the gauge control module self-diagnostic function - Refer to: Gauges Self-Diagnostic Function (2019 2020 2021) or Gauges Self-Diagnostic Function (2016 2017 2018) . Check the indicator drive circuit in the gauge control module by using the gauge control module self-diagnostic function - Refer to: Gauges Self-Diagnostic Function (2019 2020 2021) or Gauges Self-Diagnostic Function (2016 2017 2018) .
When you press the paddle shifter, the transmission does not upshift/downshift	A problem in the paddle shifter circuit Hot mode protection - Refer to: A/T System Description - Electronic Control System(9-Speed A/T), or A/T System Description - Electronic Control System(6-Speed A/T) Wheel slip mode - Refer to: A/T System Description - Electronic Control System(9-Speed A/T), or A/T System Description - Electronic Control System(6-Speed A/T) Winter detection mode - Refer to: A/T System Description - Electronic Control System(9-Speed A/T), or A/T System Description - Electronic Control System(6-Speed A/T) Curve detection mode - Refer to: A/T System Description - Electronic Control System(9-Speed A/T), or A/T System Description - Electronic Control System(6-Speed A/T)	Troubleshoot the paddle shifter circuit - Refer to: Paddle Shifter Circuit Troubleshooting (2019 2020 2021) or Paddle Shifter Circuit Troubleshooting (2016 2017 2018) .
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	Check the F-CAN communication line - Refer to: F-CAN Circuit Troubleshooting (2016 2017 2018: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2016 2017 2018: 6-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020 2021: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020: 6-Speed A/T) . Inspect The APP Sensor Signal . Check for a poor connection at the SBW shifter assembly.
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 (2016 2017 2018: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2016 2017 2018: 6-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020 2021: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020: 6-Speed A/T) .
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	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. Replace the torque converter - Refer to: Automatic Transmission Removal and Installation(9-Speed A/T), or Automatic Transmission Removal and Installation(6-Speed A/T) .
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(9-Speed A/T), or Stall Speed Test(6-Speed A/T) . 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	Check the ATF level - Refer to: ATF Level Check(9-Speed A/T), or ATF Level Check(6-Speed A/T) . If the level is below the lower level, check the ATF lines for leaks and loose connections. If necessary, clean the ATF lines. Check the ATF level - Refer to: ATF Level Check(9-Speed A/T), or ATF Level Check(6-Speed A/T) . If the level is above the upper level, drain the ATF if it is over-filled. Replace The Hydraulic Control Unit .
Delayed engagement after shifting, or excessive shock when shifting	Low ATF level Hydraulic control unit defective Torque converter defective Clutch clearance incorrect	Check the ATF level - Refer to: ATF Level Check(9-Speed A/T), or ATF Level Check(6-Speed A/T) . If the level is below the lower level, check the ATF lines for leaks and loose connections. If necessary, clean the ATF lines. Replace The Hydraulic Control Unit . Replace the torque converter - Refer to: Automatic Transmission Removal and Installation(9-Speed A/T), or Automatic Transmission Removal and Installation(6-Speed A/T) .
Transmission does not shift	F-CAN communication line error Low ATF level TCM defective Wrong tires	Check the F-CAN communication line - Refer to: F-CAN Circuit Troubleshooting (2016 2017 2018: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2016 2017 2018: 6-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020 2021: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020: 6-Speed A/T) . Check the ATF level - Refer to: ATF Level Check(9-Speed A/T), or ATF Level Check(6-Speed A/T) . If the level is below the lower level, check the ATF lines for leaks and loose connections. If necessary, clean the ATF lines.
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	Check the ATF level - Refer to: ATF Level Check(9-Speed A/T), or ATF Level Check(6-Speed A/T) . If the level is below the lower level, check the ATF lines for leaks and loose connections. If necessary, clean the ATF lines. Do the hydraulic pressure characteristic calibration procedure .
Engine stalls a stand still	Hydraulic control unit defective Drive plate defective or transmission incorrectly installed Torque converter defective Low ATF temperature	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. Replace the torque converter - Refer to: Automatic Transmission Removal and Installation(9-Speed A/T), or Automatic Transmission Removal and Installation(6-Speed A/T) .
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	Replace The Hydraulic Control Unit . Replace the torque converter - Refer to: Automatic Transmission Removal and Installation(9-Speed A/T), or Automatic Transmission Removal and Installation(6-Speed A/T) .
Engine stalls when shifted to N position/mode from R position/mode	Hydraulic control unit defective Torque converter defective	Replace The Hydraulic Control Unit . Replace the torque converter - Refer to: Automatic Transmission Removal and Installation(9-Speed A/T), or Automatic Transmission Removal and Installation(6-Speed A/T) .
No engine braking	Downhill detection mode - Refer to: A/T System Description - Electronic Control System(9-Speed A/T), or A/T System Description - Electronic Control System(6-Speed A/T) F-CAN communication line error Self-protection function active - Refer to: A/T System Description - Electronic Control System(9-Speed A/T), or A/T System Description - Electronic Control System(6-Speed A/T)	Check the F-CAN communication line - Refer to: F-CAN Circuit Troubleshooting (2016 2017 2018: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2016 2017 2018: 6-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020 2021: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020: 6-Speed A/T) .
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
Auto idle stop is not working	Condition for auto idle stop is not met Auto idle stop disallowed due to protection control F-CAN communication line error	Inspect The Auto Idle Stop System . Troubleshoot the auto idle stop system - Refer to: Auto Idle Stop System Symptom Troubleshooting - Auto Idle Stop System Indicator (Green/Amber) Does Not Come On or Auto Idle Stop System Symptom Troubleshooting - Auto Idle Stop System Indicator (Amber) Blinks or Auto Idle Stop System Symptom Troubleshooting - Auto Idle Stop System Does Not Operate . Check the F-CAN communication line - Refer to: F-CAN Circuit Troubleshooting (2016 2017 2018: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2016 2017 2018: 6-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020 2021: 9-Speed A/T) or F-CAN Circuit Troubleshooting (2019 2020: 6-Speed A/T) .