Five free practice questions on automatic transmission diagnosis: content area A of the ASE A2 Automatic Transmission/Transaxle test, 26 of its 45 scored questions (57.8%). They are in the ASE format: four options, one best answer. Answer each one before opening the explanation. No account, no email.
01The questions
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A hybrid pickup has a stepped automatic transmission with an electric motor in place of the torque converter and a wet clutch between the engine and the motor. What lets the truck drive on the motor alone with the engine stopped?
- The transmission shifts to Neutral for electric drive
- The transmission's forward clutch is released
- The engine's fuel is shut off and it turns with the motor
- The clutch between the engine and the motor is released
Show the answer
D. Correct. Releasing the engine disconnect clutch separates the stopped engine from the motor, so the motor drives the transmission input by itself; the clutch is applied again to start the engine or add its power. The stepped gearbox keeps working the same way in electric and engine drive.
Why not the others
A. In Neutral the gear train carries no power from the motor to the wheels. The motor drives through the transmission in gear; only the engine is disconnected, by releasing the clutch between it and the motor.
B. Releasing the transmission's forward clutch would disconnect the motor from the gear train as well, so nothing would drive the wheels. The clutch that is released is the one between the engine and the motor.
C. With fuel shut off and the clutch still applied, the engine would be spun by the motor, not stopped, wasting energy. Electric drive with the engine stopped needs the clutch between the engine and the motor released.
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While the technician drives in 2nd gear, the scan tool's data list shows 'Shift solenoid B command: ON'. What does this data item show by itself?
- That the solenoid's plunger has moved fully
- What the TCM is commanding the solenoid to do
- That the circuit current is at its normal level
- That the shift valve it controls has stroked
Show the answer
B. Correct. A solenoid state in the data list is the TCM's command, the output it is trying to produce. Whether the solenoid, its circuit and the hydraulics actually respond is confirmed separately, by circuit tests, current readings or the resulting gear ratio.
Why not the others
A. The data item reports the TCM's command, not a measurement of the plunger. A solenoid can be commanded on with a stuck plunger, which takes a current waveform or a hydraulic result to find.
C. A commanded ON does not report current; a circuit with high resistance can show ON while too little current flows. Current is measured with a low-amp probe or found through circuit tests.
D. The command does not report the shift valve's position, so ON says nothing about whether the valve moved. The gear ratio from the input and output speed readings shows whether the expected shift happened.
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With the fluid level correct and the fluid at operating temperature, line pressure in every range is below the manufacturer's specification at idle but rises to within specification at 1,500 rpm. Which of these is the most likely cause?
- A worn fluid pump
- A clogged fluid filter
- A regulator valve stuck at high pressure
- A leaking forward clutch circuit
Show the answer
A. Correct. Worn pump clearances let a large share of output leak back at idle, where output is smallest; as speed rises, output outruns the leakage and pressure recovers. A large leak common to every range acts the same way, so pump clearances and the seal rings it feeds are checked next.
Why not the others
B. A clogged filter restricts the pump inlet more as flow rises, so pressure is usually near normal at idle and falls off at higher engine speed, the reverse of this pattern. Low at idle and recovering with speed points to the pump.
C. A regulator valve stuck toward high pressure makes readings higher than specification, not lower. Low readings that recover with engine speed point to a worn pump.
D. The forward clutch is applied only in the forward ranges, so its leak could not lower pressure in Park, Neutral and Reverse. Low in every range points to the supply, the pump.
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A transaxle's solenoid chart reads: 1st, A on and B on; 2nd, A off and B on; 3rd, A off and B off; 4th, A on and B off. Solenoid A's circuit has opened, so A stays off whatever the TCM commands, and the TCM keeps commanding its normal shifts. Which gears does the transaxle give when 1st, 2nd, 3rd and 4th are commanded?
- Second, second, third and third
- First, first, fourth and fourth
- Fourth, third, third and fourth
- Third in all four cases
Show the answer
A. Correct. With A forced off, commanded 1st (A on, B on) becomes A off, B on, which is 2nd; 2nd stays 2nd; 3rd stays 3rd; commanded 4th (A on, B off) becomes A off, B off, which is 3rd. The driver feels a 2nd-gear start and no 4th, a pattern that points straight at solenoid A.
Why not the others
B. This is solenoid A stuck on: 2nd (A off, B on) would become A on, B on, which is 1st, and 3rd would become 4th. With A stuck off, the gears are 2nd, 2nd, 3rd and 3rd.
C. This is the result for solenoid B stuck off, not A: 1st would become A on, B off (4th) and 2nd would become 3rd. With A stuck off, the gears are 2nd, 2nd, 3rd and 3rd.
D. 3rd in every case is what both solenoids off would give, as in a failsafe with all solenoids switched off. Only A is off here and B still follows commands, so the gears are 2nd, 2nd, 3rd and 3rd.
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A vehicle is in for harsh, erratic shifts, and the TCM stores no DTCs. Why does the technician scan every module on the vehicle for DTCs before diagnosing the transmission?
- Scanning every module resets the TCM's adapts
- A full scan is needed before output tests run
- Faults in other modules can affect shifting
- Reading every module wakes a sleeping TCM
Show the answer
C. Correct. The TCM depends on data from the ECM, the ABS module and others over the network, so a DTC in one of them, such as a sensor or communication fault, can explain a shift complaint with no TCM DTC. Finding it first avoids diagnosing a transmission that is only reacting to bad data.
Why not the others
A. Reading DTCs does not change the TCM's learned values. The full scan is done because a fault in another module can upset shifting without setting a TCM DTC.
B. Output tests do not depend on reading other modules' DTCs first. The full scan looks for faults elsewhere, such as in the ECM or ABS module, that can cause a shift complaint.
D. The TCM is awake whenever the ignition is on; reading other modules does nothing to it. The full scan is done because faults in other modules can affect shifting.
02Answer key
| Question | Answer |
|---|---|
| Q1 | D |
| Q2 | B |
| Q3 | A |
| Q4 | A |
| Q5 | C |
03What area A covers
This content area covers finding the cause of an automatic transmission complaint. Questions span conventional, dual-clutch, CVT and hybrid units: fluid checks, road tests, noise and shift-quality problems, line pressure and stall tests, torque converter and TCC faults, stop/start pumps, OBD II codes and enable criteria, scan tool data, network and charging faults, module programming, and DMM and lab scope tests.
The ASE test specification calls this content area “Transmission/Transaxle Diagnosis”. It carries 26 of the 45 scored questions, 57.8% of the test.
- Identify the transmission type and verify the concern
- Check fluid type, level and condition
- Road test for shift, noise and slip complaints
- Run line pressure, stall and TCC tests
- Read DTCs, enable criteria and freeze-frame data
- Test solenoids, sensors and circuits with a DMM or scope
- Separate transmission faults from engine, ABS and network faults
- Replace, program and configure control modules
04What the questions turn on
Compare pressure range by range
Line pressure is judged in each range. Pressure low in only one range points to a circuit used only in that range, while a clogged filter starves the pump and lowers pressure overall, which gives slips and flares rather than harsh shifts.
Stall speed high or low
A stall speed above specification points to a slipping clutch or band, or low apply pressure. A stator one-way clutch that freewheels cannot redirect fluid back to the impeller, so torque multiplication is lost and stall speed falls below specification.
A command is not a result
Scan data shows what the TCM commands, not what happened. A circuit DTC sets when driver monitoring sees an open, short or out-of-range value; a performance DTC means the circuit looks normal but the expected result, such as the gear ratio, did not follow.
Enable criteria come first
A diagnostic runs only when all its enable criteria, such as fluid temperature, gear and speed, are met; until then it neither passes nor fails. A permanent DTC is erased by the module itself once that test runs and passes on a qualifying drive.
05The other content areas
The A2 test has three content areas. Each has its own page of free questions:
The ASE A2 Automatic Transmission/Transaxle practice test page describes the full question bank. How these questions are written and checked: how our questions are made. Found a mistake? Tell us and we will fix it.
ToolboxPrep is an independent study site. It is not affiliated with or endorsed by ASE (the National Institute for Automotive Service Excellence). Our questions are original practice questions written to the published ASE test specifications; they are not actual test questions.