A/T System Symptom Troubleshooting Index (2019, 2020, 2021)

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
HDS does not communicate with the PCM	DLC circuit error PCM defective	Troubleshoot the DLC circuit - Refer to: DLC Circuit Troubleshooting (2019 - 2021) or DLC Circuit Troubleshooting (2022 - 2023) .
HDS does not communicate with the TCM	DLC circuit error TCM communication circuit error	Troubleshoot the DLC circuit - Refer to: DLC Circuit Troubleshooting (2019 - 2021) or DLC Circuit Troubleshooting (2022 - 2023) . Check the TCM communication circuit.
Shift position indicator blinks current position/mode for 2 seconds intervals (no DTCs are stored)	TCM SET UP procedure unfinished	Do the TCM SET UP procedure completely .
Shift position indicator displays an improper position/mode	F-CAN circuit error Gauge control module defective SBW shifter assembly defective TCM defective	Check the F-CAN circuit. Check the F-CAN communication line by using the gauge control module self-diagnostic function . Check the indicator drive circuit in the gauge control module by using the gauge control module self-diagnostic function . Replace the SBW shifter assembly . Replace the TCM (included in the valve body assembly) .
M indicator does not come on even though paddle shifter is operated in sequential sportshift mode	F-CAN circuit error Gauge control module defective SBW shifter assembly defective	Check the F-CAN circuit. Check the F-CAN communication line by using the gauge control module self-diagnostic function . Check the indicator drive circuit in the gauge control module by using the gauge control module self-diagnostic function . Replace the SBW shifter assembly .
Transmission does not upshift/downshift when operating paddle shifter	Paddle shifter circuit error TCM defective	Paddle shifter circuit troubleshooting . Replace the TCM (included in the valve body assembly) .
Engine runs, but vehicle does not move in any positions/modes	Low ATF level Drive plate defective Transmission incorrectly installed Torque converter defective Axle disengaged or damaged Valve body assembly defective Transmission defective TCM defective	Check the ATF level and condition . Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter . Replace the valve body assembly (including with the TCM) . Replace the transmission .
Vehicle moves in R, but not in D	Valve body assembly defective Transmission defective TCM defective	Replace the valve body assembly (including with the TCM) . Replace the transmission .
Vehicle moves in D, but not in R	Valve body assembly defective Transmission defective TCM defective	Replace the valve body assembly (including with the TCM) . Replace the transmission .
Poor acceleration; engine revs up abnormally high when starting off in D and R	Low ATF level Drive plate defective Transmission incorrectly installed Torque converter defective Valve body assembly defective Transmission defective	Check the ATF level and condition . Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter . Replace the valve body assembly . Replace the transmission .
Poor acceleration; stall speed high in D	Valve body assembly defective Transmission defective	Replace the valve body assembly . Replace the transmission .
Poor acceleration; stall speed high in R	Valve body assembly defective Transmission defective	Replace the valve body assembly . Replace the transmission .
Poor acceleration; stall speed low	Torque converter defective	Replace the torque converter .
Engine idle vibration	Torque converter defective	Replace the torque converter .
Vehicle moves in N	Excessive ATF level Valve body assembly defective Transmission defective	Check the ATF level and condition . Replace the valve body assembly . Replace the transmission .
Delayed engagement after shifting from N to D, or excessive shock when shifting	Valve body assembly defective Transmission defective	Replace the valve body assembly . Replace the transmission .
Delayed engagement after shifting from N to R, or excessive shock when shifting	Valve body assembly defective Transmission defective	Replace the valve body assembly . Replace the transmission .
Excessive shock on all upshifts and downshifts	Low ATF level ATF deteriorated	Check the ATF level and condition .
Noise from transmission in all positions/modes	Drive plate defective Transmission incorrectly installed Torque converter defective Valve body assembly defective Transmission defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter . Replace the valve body assembly . Replace the transmission .
Noise from transmission while driving	Drive plate defective Transmission incorrectly installed Torque converter defective Valve body assembly defective Transmission defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter . Replace the valve body assembly . Replace the transmission .
Vibration in all positions/modes	Drive plate defective Transmission incorrectly installed Torque converter defective Valve body assembly defective Transmission defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter . Replace the valve body assembly . Replace the transmission .
Transmission will not shift into P, or transmission cannot shift out of P	Transmission defective	Replace the transmission .
Torque converter clutch does not disengage; engine stalls easily	Drive plate defective Transmission incorrectly installed Torque converter defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter .
Torque converter clutch does not disengage; no power at low to medium speed	Drive plate defective Transmission incorrectly installed Torque converter defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter .
Torque converter clutch does not disengage; booming noise or vibration at low to medium speed	Drive plate defective Transmission incorrectly installed Torque converter defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter .
Torque converter clutch does not disengage; excessive shift shock	Drive plate defective Transmission incorrectly installed Torque converter defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter .
Torque converter clutch does not operate smoothly	Drive plate defective Transmission incorrectly installed Torque converter defective Valve body assembly defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter . Replace the valve body assembly .
Torque converter clutch does not engage	Drive plate defective Transmission incorrectly installed Torque converter defective Valve body assembly defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter . Replace the valve body assembly .
Shift position indicator does not work	TCM defective	Replace the TCM (included in the valve body assembly) .
Speedometer and odometer do not work	Countershaft speed sensor defective TCM defective	Replace the countershaft speed sensor . Replace the TCM (included in the valve body assembly) .
Engine does not start	Drive plate defective Transmission incorrectly installed Torque converter defective Valve body assembly defective Transmission defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter . Replace the valve body assembly . Replace the transmission .
Engine stalls when shifted to D from N	Drive plate defective Transmission incorrectly installed Torque converter defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter .
Engine stalls when shifted to R from N	Drive plate defective Transmission incorrectly installed Torque converter defective	Check the drive plate for wear and damage . Replace the drive plate if it is worn or damaged . Check for an incorrectly installed transmission . Replace the torque converter .