LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Acura >> 2008 >> TL Base >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Automatic Transmission >> Symptom Troubleshooting Index
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Symptom Troubleshooting Index

SYMPTOM TROUBLESHOOTING INDEX

Symptom Probable cause(s) Notes
When you turn the ignition switch to ON (II), the D indicator comes on and stays on in all shift lever positions, or it never comes on at all
  • F-CAN communication line error
  • Gauge control module defective
  • PCM defective
A/T gear position indicator does not come on while the shift lever is in that position
  • F-CAN communication line error
  • Gauge control module defective
  • PCM defective
  • Transmission range switch defective
Shift indicator does not work
  • F-CAN communication line error
  • Gauge control module defective
  • PCM defective
When you press the paddle shifter + (upshift switch) in M, the transmission does not upshift gears A problem in the paddle shifter + (upshift switch) circuit Check the paddle shifter + (upshift switch) circuit (see PADDLE SHIFTER + (UPSHIFT SWITCH) CIRCUIT TROUBLESHOOTING  ).
When you press the paddle shifter - (downshift switch) in M, the transmission does not downshift gears A problem in the paddle shifter - (downshift switch) circuit Check the paddle shifter - (downshift switch) circuit (see PADDLE SHIFTER - (DOWNSHIFT SWITCH) CIRCUIT TROUBLESHOOTING  ).
Shift lever cannot be moved from P while you are pressing on the brake pedal
  1. A problem in the shift lock system of the interlock system
  2. Accelerator pedal position sensor circuit
Shift lever cannot pass through R from N A problem in the reverse lock system of the interlock system Check the interlock system - reverse lock system circuit (see SHIFT LOCK SYSTEM/REVERSE LOCK SYSTEM CIRCUIT TROUBLESHOOTING  ).
Ignition switch cannot be moved from ACCESSORY (1) to LOCK (0) (key is pushed in, the shift lever in P) A problem in the key interlock system of the interlock system Check the interlock system - key interlock system circuit (see KEY INTERLOCK SYSTEM CIRCUIT TROUBLESHOOTING  ).
Engine runs, but vehicle does not move in any gear
  1. Low ATF level
  2. Shift cable broken or out of adjustment
  3. Connection between the shift cable and the transmission or the body is worn
  4. ATF pump worn or binding
  5. Regulator valve stuck or the spring worn
  6. ATF strainer clogged
  7. Mainshaft worn or damaged
  8. Final gears worn or damaged
  9. Park mechanism defective
  10. Transmission-to-engine assembly error
  11. Axle disengaged
  • Check the ATF level and check the ATF cooler lines for leakage and loose connections. If necessary, clean the ATF cooler lines.
  • Check for a loose shift cable at the shift lever and the transmission control lever.
  • Improper alignment of the ATF pump and the torque converter housing may cause ATF pump seizure. The symptoms are mostly an rpm-related ticking noise or a high pitched squeak.
  • Check the line pressure.
  • Check the ATF strainer for debris. If the strainer is clogged, find the damaged components that caused the debris.
  • Inspect the differential pinion gears for wear. If the differential pinion gears are worn, replace the differential assembly, replace the ATF strainer, and thoroughly clean the transmission, and clean the cooler and lines. Replace the torque converter.
  • Be careful not to damage the torque converter housing when replacing the main ball bearing. You may also damage the ATF pump when you torque down the main valve body. This will result in ATF pump seizure if not detected. Use the proper tools.
  • Install the main seal flush with the torque converter housing. If you push it into the torque converter housing until it bottoms out, it will block the fluid return passage and result in damage.
Vehicle moves in R, but not in D, L, or 1st in M
  1. 1st accumulator defective
  2. Idler gears worn or damaged
  3. 1st clutch defective
  • Check the 1st clutch pressure.
  • Inspect the secondary shaft and the 1st/1st-hold clutch assembly for wear and damage.
  • Inspect the clutch piston and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Vehicle moves in D, L, and R, but not in 1st in M
  1. 1st-hold accumulator defective
  2. 1st-hold clutch defective
  • Check the 1st-hold clutch pressure.
  • Inspect the secondary shaft and the 1st/1st-hold clutch assembly for wear and damage.
  • Inspect the clutch piston and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Vehicle moves in D, L, and R, but not in 2nd in M
  1. 2nd accumulator defective
  2. 2nd clutch defective
  • Check the 2nd clutch pressure.
  • Inspect the secondary shaft and the 2nd clutch assembly for wear and damage.
  • Inspect the clutch piston and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Vehicle moves in D, L, and M, but not in R (or moves forward in R)
  1. Shift fork shaft stuck
  2. Modulator valve defective
  3. Reverse CPC valve defective
  4. 5th accumulator defective
  5. 5th clutch defective
  6. Reverse gears worn or damaged
  • Check the line pressure and the 5th clutch pressure.
  • Check for a missing shift fork bolt on the shift fork shaft.
  • Check the ATF strainer for debris. If the ATF strainer is clogged with particles of steel or aluminum, inspect the ATF pump. If the ATF pump is OK, find the damaged components that caused the debris. If no cause for the contamination is found, replace the torque converter.
  • Inspect the reverse selector gear teeth chamfers, and inspect the engagement teeth chamfers of the countershaft 5th gear and the reverse gear. Replace the reverse gears and the reverse selector if they are worn or damaged. If the transmission makes clicking, grinding, or whirring noises, also replace the mainshaft 5th gear, the reverse idler gear, and the countershaft 5th gear.
  • Inspect the clutch piston, the clutch piston check valve, and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clearance with the clutch end-plate.
Poor acceleration; flares when starting off in D, L, and R; stall speed high in R
  1. Low ATF level
  2. Shift cable broken or out of adjustment
  3. ATF pump worn or binding
  4. Regulator valve stuck or the spring worn
  5. ATF strainer clogged
  6. Torque converter check valve defective
  • Check the ATF level and check the ATF cooler lines for leakage and loose connections. If necessary, clean the ATF cooler lines.
  • Check for a loose shift cable at the shift lever and the transmission control lever.
  • Check the line pressure.
  • Check the ATF strainer for debris. If the strainer is clogged, find the damaged components that caused the debris.
  • Improper alignment of the ATF pump and the torque converter housing may cause ATF pump seizure. The symptom is mostly an rpm-related ticking noise or a high pitched squeak.
  • Be careful not to damage the torque converter housing when replacing the main ball bearing. You may also damage the ATF pump when you torque down the main valve body. This will result in ATF pump seizure if not detected. Use the proper tools.
Poor acceleration; flares when starting off in D, L, and R; stall speed high in D and L
  1. 1st accumulator defective
  2. 1st clutch defective
  • Check the 1st clutch pressure.
  • Inspect the clutch piston and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Poor acceleration; flares when starting off in D, L, and R
  1. Shift solenoid valve C defective
  2. Shift cable broken or out of adjustment
  3. Reverse CPC valve defective
  4. 5th accumulator defective
  5. 5th clutch defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the O-ring, and check the shift solenoid valve seizure.
  • Check for a loose shift cable at the shift lever and the transmission control lever.
  • Check the 5th clutch pressure.
  • Inspect the clutch piston and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Poor acceleration; flares when starting off in D, L, and R; stall speed low
  1. Shift solenoid valve D defective
  2. Torque converter one-way clutch defective
  3. Engine output low
  4. Torque converter clutch piston defective
  5. Lock-up shift valve defective
 Check for a stuck lock-up valve in the valve body.
Engine idle vibration
  1. Low ATF level
  2. Torque converter clutch solenoid valve defective
  3. Drive plate defective or transmission misassembled
  4. Engine output low
  5. Torque converter clutch piston defective
  6. ATF pump worn or binding
  7. Lock-up shift valve defective
  • Adjust the engine and the transmission mounts.
  • Check the ATF level and check the ATF cooler lines for leakage and loose connections. If necessary, clean the ATF cooler lines.
Vehicle moves in N
  1. Excessive ATF
  2. Foreign material in separator plate orifice
  3. Relief valve defective
  4. Lubrication control valve defective
  5. 1st-hold clutch defective
  6. 1st clutch defective
  7. 2nd clutch defective
  8. 3rd clutch defective
  9. 4th clutch defective
  10. 5th clutch defective
  11. Clearance between the clutch end-plate and the top disc
  12. Needle bearing seized, worn, or damaged
  13. Thrust washer seized, worn, or damaged
  • Check the ATF level, and drain the ATF if necessary.
  • Check all clutch pressures.
  • Inspect the clutch piston, the clutch piston check valve, and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Late shift after shifting from N to D or L, or excessive shock when shifting
  1. Shift solenoid valve C defective
  2. A/T clutch pressure control solenoid valve A defective
  3. A/T clutch pressure control solenoid valve B defective
  4. A/T clutch pressure control solenoid valve C defective
  5. Shift cable broken or out of adjustment
  6. Connection between shift cable and the transmission or the body is worn
  7. Input shaft (mainshaft) speed sensor defective
  8. Output shaft (countershaft) speed sensor defective
  9. ATF temperature sensor defective
  10. CPC valve A defective
  11. CPC valve B defective
  12. CPC valve C stuck
  13. Foreign material in separator plate orifice
  14. Shift valve C defective
  15. Shift valve E defective
  16. Servo control valve defective
  17. 1st accumulator defective
  18. 1st check ball stuck
  19. One-way check ball stuck
  20. 1st clutch defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the O-ring, and check the shift solenoid valve for seizure.
  • Inspect the A/T clutch pressure control solenoid valve body gasket and the ATF feed pipes for wear and damage. If the A/T clutch pressure control solenoid valve is stuck, inspect the CPC valves.
  • Check for a loose shift cable at the shift lever and the transmission control lever.
  • Check the 1st clutch pressure.
  • Inspect the clutch piston, the clutch piston check valve, and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Late shift after shifting from N to R, or excessive shock when shifting
  1. Shift solenoid valve C defective
  2. A/T clutch pressure control solenoid valve B defective
  3. A/T clutch pressure control solenoid valve C defective
  4. Shift cable broken or out of adjustment
  5. Connection between shift cable and the transmission or the body is worn
  6. Input shaft (mainshaft) speed sensor defective
  7. Output shaft (countershaft) speed sensor defective
  8. ATF temperature sensor defective
  9. Shift fork shaft stuck
  10. CPC valve C stuck
  11. Reverse CPC valve defective
  12. Foreign material in separator plate orifice
  13. Shift valve E defective
  14. 5th accumulator defective
  15. 5th clutch defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the O-ring, and check the shift solenoid valve for seizure.
  • Inspect the A/T clutch pressure control solenoid valve body gasket and the ATF feed pipes for wear and damage. If the A/T clutch pressure control solenoid valve is stuck, inspect the CPC valves.
  • Check for a loose shift cable at the shift lever and the transmission control lever.
  • Check the 5th clutch pressure.
  • Inspect the clutch piston, the clutch piston check valve, and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Transmission does not shift
  1. Input shaft (mainshaft) speed sensor defective
  2. Output shaft (countershaft) speed sensor defective
  3. Modulator valve defective
  • Check for a stored DTC, and check for loose connectors.
  • Check the line pressure.
Erratic shifting: fails to shift in D and L; starts off in 5th
  1. Shift solenoid valve B defective
  2. Shift valve B defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the O-ring, and check the shift solenoid valve for seizure.
Erratic shifting: fails to shift in 2nd in M; starts off in 4th
  1. Shift solenoid valve B defective
  2. Shift valve B defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the O-ring, and check the shift solenoid valve for seizure.
Erratic shifting: fails to shift in D, L, and 1st in M; starts off in 3rd
  1. Shift solenoid valve A defective
  2. Shift valve A defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the O-ring, and check the shift solenoid valve for seizure.
Erratic shifting: fails to shift in 2nd in M; starts off in 1st
  1. Shift solenoid valve A defective
  2. Shift valve A defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the O-ring, and check the shift solenoid valve for seizure.
Excessive shock or flares on all upshifts and downshifts
  1. A/T clutch pressure control solenoid valve A defective
  2. Input shaft (mainshaft) speed sensor defective
  3. Output shaft (countershaft) speed sensor defective
  4. ATF temperature sensor defective
  5. CPC valve A defective
  6. Foreign material in separator plate orifice
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the A/T clutch pressure control solenoid valve body gasket and the ATF feed pipes for wear and damage. If the A/T clutch pressure control solenoid valve is stuck, inspect the CPC valves.
  • Inspect the sensor O-rings.
Excessive shock or flares on 1-2 upshift or 2-1 downshift
  1. A/T clutch pressure control solenoid valve A defective
  2. A/T clutch pressure control solenoid valve C defective
  3. 2nd clutch transmission fluid pressure switch defective
  4. CPC valve A defective
  5. CPC valve C defective
  6. Foreign material in separator plate orifice
  7. 2nd accumulator defective
  8. 2nd check ball stuck
  9. 2nd clutch defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the A/T clutch pressure control solenoid valve body gasket and the ATF feed pipes for wear and damage. If the A/T clutch pressure control solenoid valve is stuck, inspect the CPC valves.
  • Check for clogged orifice in the transmission fluid pressure switch connector. If the orifice is clogged, remove it and clean the connector.
  • Check the 1st and 2nd clutch pressures.
  • Inspect the clutch piston, the clutch check valve, and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Excessive shock or flares on 2-3 upshift or 3-2 downshift
  1. Shift solenoid valve C defective
  2. A/T clutch pressure control solenoid valve B defective
  3. A/T clutch pressure control solenoid valve C defective
  4. 3rd clutch transmission fluid pressure switch defective
  5. CPC valve B defective
  6. CPC valve C defective
  7. Foreign material in separator plate orifice
  8. Shift valve C defective
  9. 2nd accumulator defective
  10. 3rd accumulator defective
  11. 2nd check ball stuck
  12. 2nd clutch defective
  13. 3rd clutch defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the O-rings, and check the shift solenoid valve for seizure.
  • Inspect the A/T clutch pressure control solenoid valve body gasket and the ATF feed pipes for wear and damage. If the A/T clutch pressure control solenoid valve is stuck, inspect the CPC valves.
  • Check for clogged orifice in the transmission fluid pressure switch connector. If the orifice is clogged, remove it and clean the connector.
  • Check the 2nd and 3rd clutch pressures.
  • Inspect the clutch piston, the clutch check valve and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Excessive shock or flares on 3-4 upshift or 4-3 downshift
  1. Shift solenoid valve C defective
  2. A/T clutch pressure control solenoid valve B defective
  3. A/T clutch pressure control solenoid valve A defective
  4. 4th clutch transmission fluid pressure switch defective
  5. CPC valve A defective
  6. CPC valve B defective
  7. Foreign material in separator plate orifice
  8. Shift valve C defective
  9. 3rd accumulator defective
  10. 4th accumulator defective
  11. 3rd clutch defective
  12. 4th clutch defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the O-rings, and check the shift solenoid valve for seizure.
  • Inspect the A/T clutch pressure control solenoid valve body gasket and the ATF feed pipes for wear and damage. If the A/T clutch pressure control solenoid valve is stuck, inspect the CPC valves.
  • Check for clogged orifice in the transmission fluid pressure switch connector. If the orifice is clogged, remove it and clean the connector.
  • Check the 3rd and 4th clutch pressures.
  • Inspect the clutch piston, the clutch check valve and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Excessive shock or flares on 4-5 upshift or 5-4 downshift
  1. Shift solenoid valve C defective
  2. A/T clutch pressure control solenoid valve B defective
  3. A/T clutch pressure control solenoid valve C defective
  4. CPC valve B defective
  5. CPC valve C defective
  6. Foreign material in separator plate orifice
  7. Shift valve C defective
  8. Shift valve E defective
  9. Kick-down valve or kick-down short valve defective
  10. 4th accumulator defective
  11. 5th accumulator defective
  12. 4th clutch defective
  13. 5th clutch defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the O-rings, and check the shift solenoid valve for seizure.
  • Inspect the A/T clutch pressure control solenoid valve body gasket and the ATF feed pipes for wear and damage. If the A/T clutch pressure control solenoid valve is stuck, inspect the CPC valves.
  • Check the 4th and 5th clutch pressures.
  • Inspect the clutch piston, the clutch check valve and the O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage. If the discs and the plates are worn or damaged, replace them as a set. If they are OK, adjust the clutch end-plate clearance.
Noise from transmission in all shift lever positions
  1. ATF pump worn or binding
  2. Idler gears worn or damaged
  3. Thrust washer seized up, worn, or damaged
 Improper alignment of ATF pump and the torque converter housing may cause ATF pump seizure. The symptoms are mostly an rpm-related ticking noise or a high pitched squeak.
Vehicle does not accelerate above 31 mph (50 km/h) Torque converter one-way clutch defective Replace the torque converter.
Vibration in all shift lever positions Drive plate defective or transmission misassembled
  • Adjust the engine and the transmission mounts.
  • Check the stall speed.
Shift lever does not operate smoothly
  1. Transmission range switch defective or out of adjustment
  2. Shift cable broken or out of adjustment
  3. Connection between shift cable and the transmission or the body is worn
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the transmission range switch. If the transmission range switch is faulty, replace it. If the transmission range switch is out of adjustment, adjust it and the shift cable.
  • Check for a loose shift cable at the shift lever and the transmission control lever.
Transmission does not shift into P
  1. Shift cable broken or out of adjustment
  2. Connection between shift cable and transmission or body is worn
  3. Park mechanism defective
  • Check for a loose shift cable at the shift lever and the transmission control lever.
  • Check the park pawl, the control shaft, and the park lever link for wear and damage. Check if the control shaft lever pin is disengaged from the manual valve guide.
Torque converter clutch does not disengage
  1. Shift solenoid valve D defective
  2. A/T clutch pressure control solenoid valve C defective
  3. Torque converter clutch piston defective
  4. Lock-up shift valve defective
  5. Lock-up control valve defective
  6. Lock-up timing valve defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the A/T clutch pressure control solenoid valve C body gasket for wear and damage. If A/T clutch pressure control solenoid valve C is stuck, inspect the CPC valves.
Torque converter clutch does not operate smoothly
  1. Shift solenoid valve D defective
  2. A/T clutch pressure control solenoid valve C defective
  3. Lock-up clutch piston defective
  4. Torque converter check valve defective
  5. Lock-up shift valve defective
  6. Lock-up control valve defective
  7. Lock-up timing valve defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the A/T clutch pressure control solenoid valve C body gasket for wear and damage. If A/T clutch pressure control solenoid valve C is stuck, inspect the CPC valves.
  • Center all engine mounts.
Torque converter clutch does not engage
  1. Shift solenoid valve D defective
  2. A/T clutch pressure control solenoid valve C defective
  3. Input shaft (mainshaft) speed sensor defective
  4. Output shaft (countershaft) speed sensor defective
  5. Torque converter clutch piston defective
  6. Torque converter check valve defective
  7. Lock-up shift valve defective
  8. Lock-up control valve defective
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the A/T clutch pressure control solenoid valve C body gasket for wear and damage. If A/T clutch pressure control solenoid valve C is stuck, inspect the CPC valves.
A/T gear position indicator does not indicate shift lever positions
  1. Transmission range switch defective or out of adjustment
  2. Shift cable broken or out of adjustment
  3. Connection between shift cable and the transmission or the body is worn
  • Check for a stored DTC, and check for loose connectors.
  • Inspect the transmission range switch. If the transmission range switch is faulty, replace it. If the transmission range switch is out of adjustment, adjust it and the shift cable.
  • Check for a loose shift cable at the shift lever and the transmission control lever.
Speedometer and odometer do not work Output shaft (countershaft) speed sensor defective Check for a stored DTC, and check for loose connectors.
Engine does not rev to high rpm, and the transmission upshifts at low rpm (engine at normal operating temperature) VTEC rocker arms defective
  • Check the engine rocker arms.
  • Check for a restricted or damaged exhaust.
scientia non olet · About LEMON Manuals