A/T System Symptom Troubleshooting Index

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 . 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 . 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 . 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 . 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 . 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 .
When you press the paddle shifter, the transmission does not upshift/downshift	A problem in the paddle shifter circuit Hot mode protection Wheel slip mode Winter detection mode Curve detection mode	Troubleshoot the paddle shifter 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 . Inspect the APP sensor signal . Check for a poor connection at the SBW shifter assembly.
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	Check the F-CAN communication line . 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 . Check for a poor connection at the SBW shifter assembly. Inspect the paddle shifter .

Symptom	Probable cause(s)	Notes
HDS does not communicate with the TCM	F-CAN communication line error TCM defective	Check the F-CAN communication line .
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 .
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 . 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 . 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 . 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 . 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 .
Transmission does not shift	F-CAN communication line error Low ATF level TCM defective Wrong tires	Check the F-CAN communication line . Check the ATF level . 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 . 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 .
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 .

Symptom	Probable cause(s)	Notes
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 .
No engine braking	Downhill detection mode F-CAN communication line error Self-protection function active	Check the F-CAN communication line .
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 (amber) blinks or Auto Idle Stop System Symptom Troubleshooting - Auto idle stop system does not operate (2022 2023) or Auto Idle Stop System Symptom Troubleshooting - Auto idle stop system indicator (green/amber) does not come on or Auto Idle Stop System Symptom Troubleshooting - Starter System Counter Inspection (2022 2023) or Auto Idle Stop System Symptom Troubleshooting - Auto idle stop system does not operate . Check the F-CAN communication line .