1. ASA Research Symposium 2016
Measuring Baseline Data for Linear
Solenoids used in Late-model Automatic Transmissions
Sean Boyle
SIUC Automotive Technology

2. Project description
Today’s vehicles have very complicated computer controlled transmissions.
Utilize various solenoids to control the quality of the shifts
May incorporate as many as 9 solenoids
Cost of servicing or overhauling these transmissions can become quite expensive
Many repair facilities would replace solenoids during a transmission overhaul as a matter of practice
Now it’s cost prohibitive
Off-shore replacement product is not as reliable

3. Project description Reuse a solenoid Pro’s Con’s
Save money on overhaul
Experienced part
Reduce unnecessary waste
Con’s
Maybe the root cause of failure
Borderline solenoids may cause future failure

4. Project description Replace a solenoid Pro’s Con’s
Might be the most reliable solution
Match solenoid to the failed component
Con’s
Potentially wasteful
New doesn’t always mean good – Never Ever Worked
Increases expense to the overhaul – less profit or high cost of rebuild
Aftermarket and OE solenoids might be made in Mexico, China, India – Questionable QC

5. Project description Testing a solenoid Electrical resistance test
Checks the windings for proper resistance
No load through the solenoid
Does not check the hydraulic or mechanical functions of the solenoid
Control via a diagnostic tool
Allows control of the solenoid
Combined with an amp clamp and voltage drop, it can evaluate the electrical operation
Does not verify the hydraulic or mechanical functions of the solenoid
Testing on a valve body machine
Checks the electrical integrity
Verifies the hydraulic and mechanical functions
Very expensive

6. Objective:
Can solenoids be adequately tested using the common equipment and tools found in a typical transmission repair facility?
Common tools
digital storage oscilloscope
multi-meter
heated cooler flusher
Common Solenoids
Honda/Acura Clutch Pressure Control Solenoids
Dodge/Chrysler 545RFE Solenoids
Mercedes Solenoids
GM/Ford 6F50/6T70 Solenoids

7. Project Phases:
Phase One: Acquire oscilloscope patterns showing frequency and duty cycle ranges of solenoids.
Phase Two: Construct test components
Heated cooler flusher
Adapters for Solenoid Assemblies
Orifice plugs
Solenoid control box
Provide independent frequency and pulse width modulation control.
Generate various “ramps” that will alter the PWM in a controlled manner
Phase Three: Generate graphs of known-good solenoids
Phase Four: Generate graphs of known-bad solenoids

8. Phase One: GM EPC Solenoid
Minimum Line Pressure = 58psi
Frequency = 585Hz
Duty Cycle = 51%

9. Phase One: GM EPC Solenoid
Minimum Line Pressure = 234psi
Frequency = 585Hz
Duty Cycle = 12%

10. Phase One: Honda/Acura CPC Solenoid
CPC A Low Duty Cycle = 21%
CPC B Low Duty Cycle = 14%
Frequency = 244Hz

11. Phase One: Honda/Acura CPC Solenoid
CPC A High Duty Cycle = 48%
CPC B High Duty Cycle = 42%
Frequency = 244Hz

12. Phase One: FCA Solenoid
Complicated shift strategy. The solenoids operate at different pulse widths AND frequencies depending on the shift phase.
1st
2nd
3rd LR
2/4 UD OD
4th 2

13. Phase One: 2/4 FCA Solenoid
This shift takes place in four stages. This is the 2/4 solenoid, which when OFF applies pressure to the clutch
Stage One - Turn solenoid OFF to quickly fill the hydraulic circuits
Stage Two – Gradual pulses to softly engage clutch
Stage Three – Bring clutch quickly up to line pressure
Stage Four – Turn solenoid OFF to allow full line to the clutch

14. Phase One: FCA Solenoid
L/R Duty Cycle = 65% high (35% on time)
2/4 Duty Cycle = 65% high (35% on time)
Frequency = 571Hz

15. Phase One: 2/4 FCA Solenoid
2/4 pulses between 24hz and 18hz initially, then raise to about 75Hz

16. Phase One: 2/4 FCA Solenoid
The long pulse is about 15ms, then it drops to about 3ms.

17. Phase One: OD FCA Solenoid
The OD shift takes place in three stages. This is the OD solenoid, which when OFF it prevents pressure to the clutch
Stage One - PWM solenoid ON to fill hydraulic circuits
Stage Two – Modulate line pressure to the clutch for desired application feel
Stage Three – PWM solenoid ON to allow full line to the clutch

18. Phase One: OD FCA Solenoid
OD solenoid is operating at 571Hz at 64% duty cycle (36% on time). Stage one gaps are at 18Hz with a pulse of about 7.5ms. This happens for about 300ms.

19. Phase One: OD FCA Solenoid
Stage two has “on” pulses that are about 7.7ms long and operate around 50Hz

20. Phase One: OD FCA Solenoid
Stage Three goes back to “on” pulses about 7.6ms long and duty cycling the solenoid at 65% high at 571Hz.

21. Phase One: Solenoid
The Shift Pressure Solenoid varies PWM between 98% (2% on) and 65% (35% on) and operates at a frequency of 1000Hz.

22. Phase One: Solenoid
The Line Pressure Solenoid varies PWM between 76% (24% on) and 52% (48% on) and operates at a frequency of 1000Hz.

23. Phase Two: Construction
Test components
Heated cooler flusher
Adapters for Solenoid Assemblies
Orifice plugs
Solenoid control box
Provide independent frequency and pulse width modulation control.
Generate various “ramps” that will alter the PWM in a controlled manner

24. Phase Two: Heated cooler flusher
We do not have a heated cooler flusher, such as the common “hot flush.”
I am adapting a flushing system we have to use heated fluid. This involves making an aluminum tank, pickup system and fluid delivery system

25. Phase Two: Heated cooler flusher

26. Phase Two: Heated cooler flusher

27. Phase Two: Adapters for Solenoid Assemblies
Adapters need to be constructed for each solenoid tested.

28. Phase Two: Adapters for Solenoid Assemblies

29. Phase Two: Adapters for Solenoid Assemblies

30. Phase Two: Adapters for Solenoid Assemblies

31. Phase Two: Adapters for Solenoid Assemblies

32. Phase Two: Adapters for Solenoid Assemblies

33. Phase Two: Adapters for Solenoid Assemblies

34. Phase Two: Clutch Feed Orifices
The transmissions are researched to find out if any expected leakage (engineered) exists for each solenoid circuit
Various plugs need to be constructed for quick-disconnect into the solenoid output lines

35. Phase Two: Solenoid Control Box
As you can see with the captured oscilloscope patterns, the solenoids use various frequencies and pulse width modulation
A tool that can mimic the natural control of the solenoids is needed to test the solenoids
Arduino components are being researched for this task.
I spent a bit of time researching the Parallax system, but it cannot PWM at a steady frequency