5R110W P0750: Shift Solenoid A Causes & Fix

P0750 on a TorqShift is a cleaner code than most people expect. It is not a "something is wrong with the transmission" code and it is not a slipping-clutch code. It means the PCM drove shift solenoid A, watched its own feedback circuit, and saw an open. That narrows the job down to one coil, two case connector pins, the internal harness between them, and the PCM driver. The hard part is knowing which solenoid "A" is on this unit, and why losing it matters more on a 5R110W than it would on an older on/off solenoid transmission.

This guide covers what solenoid A controls, what the PCM is checking when it sets P0750, the meter checks that find the fault in about fifteen minutes, and the repair. Pin numbers, resistance specs and monitor rules come from the ATSG TorqShift manual and Ford's own OBD monitor summaries; the rest is backed by Sonnax, GEARS and Transmission Digest, all listed under Sources at the bottom.

Which solenoid is "A" on a 5R110W?

The 5R110W has no shift valves in the traditional sense. ATSG describes the solenoid body as seven variable force solenoids, a manual valve, a pressure relief ball and the TFT sensor, with one solenoid dedicated to each clutch except the forward clutch, which is applied through the manual valve. Shift solenoid A is SSPC-A, the coast clutch solenoid. Sonnax's 5R110W solenoid identification chart and the ATSG component locator both label it that way.

Recommended 5R110W parts

Parts that fix the documented causes of P0750: the solenoid kit when SSPC-A reads open, the internal harness when the solenoid tests good and the wire does not, and the ATSG manual for the pin and resistance charts.

5R110W Transmission Solenoid Kit, 3C3Z-7G383AB

$180.99View part

5R110W Internal Wiring Harness 2003-2010

$137.99View part

ATSG 5R110W TorqShift Ford Transmission Rebuild Manual

$73.99View part

The detail that matters for diagnosis is how it is built. ATSG splits the seven solenoids into two groups:

The PCM varies current between 0 and 1 amp on every one of them. On an inverse solenoid like SSPC-A, zero current means maximum output pressure. So when the circuit to SSPC-A opens up, the solenoid does not go dead and quiet the way an on/off solenoid would. It defaults to sending full pressure to the coast clutch circuit. That is by design: Ford's OBD summary describes the failsafe with all seven solenoids off as Park, Reverse, Neutral and a fixed fifth gear ("5M") with maximum line pressure, and the inverse solenoids are what hold that gear. But with only SSA lost, the coast clutch can be applied in gears where the PCM wants it released, and that is when drivers report harsh shifts, a bind on certain shifts, or odd engine braking.

What the coast clutch does

The coast clutch is in the front, overdrive section of the geartrain. Its job is engine braking and holding the overdrive planetary when the overdrive one-way clutch would otherwise freewheel on coast. Ford's 2004 OBD summary for the 5R110W shows when the PCM expects it: a coast clutch failed-off fault is detected in 1st, 3rd or 5th in a manual range, and a failed-on fault is detected during the 1-2 or 5-6 shifts. In plain terms, the coast clutch is supposed to be on in the odd gears for engine braking and has to release cleanly when the overdrive clutch takes over for 2nd and 6th. If SSPC-A is stuck at maximum pressure, the 1-2 and 5-6 shifts are where you feel it first.

What the PCM checks before it sets P0750

Ford's OBD monitor summaries split solenoid A faults into two families, and keeping them straight saves a lot of wasted parts:

• Electrical: P0750 (SSA open circuit), P0973 (SSA short to ground), P0974 (SSA short to power). The PCM monitors a feedback circuit from its own output driver. The check runs continuously, needs battery voltage between 11.0 and 15.99 volts, and has a 5 second monitoring window.
• Functional: P0751 (coast clutch failed off) and P0752 (coast clutch failed on). On the 2004-era calibrations these were the P2700 "coast clutch system" code. Ford states plainly that the 5R110W cannot isolate a shift solenoid from the rest of its clutch system using ratio, so these codes cover the solenoid, the clutch, the seals and the circuit oil together. The test needs TSS and ISS working and sets after 3 bad events.

So a P0750 by itself points at wiring and the coil. A P0751 or P0752 by itself points at hydraulics or the clutch. If you have both, fix the electrical code first, clear everything, and see whether the functional code comes back. Ford's 2010 summary also notes that the P0751/P0752 family replaced the older P27xx clutch codes, which is why a 2004 truck and a 2009 truck can show you different numbers for the same coast clutch problem.

One more code to look for in the history: P0657, actuator supply voltage circuit open. Per Ford, the 5R110W uses a single high side switch that powers all seven variable force solenoids. If that supply drops, every solenoid circuit goes open at once, and you will see a string of solenoid codes rather than P0750 alone.

Fifteen-minute diagnosis at the case connector

Start at the transmission's case connector, not under the pan. ATSG's internal component resistance chart gives the numbers:

1. Measure pins 12 and 20 with the connector unplugged. 4.1 to 4.7 ohms cold is a good coil and a good internal harness path. GEARS puts it simply: all of these solenoids should be around 4.5 ohms. A hot unit reads a little higher; open (OL) is the P0750.
2. Measure pins 3 and 20 next. SSPC-A and SSPC-B share pin 20 as their supply side. If both read open, the problem is the shared pin, the terminal, or the internal harness, not two solenoids failing on the same day.
3. Check each pin to case ground. Any continuity to the case points at a chafed internal harness wire and goes with P0973 more than P0750, but check it every time.
4. If the transmission side measures good, the open is between the case connector and the PCM. Inspect the vehicle harness connector for bent or pushed-back terminals and corrosion, and back-probe at the PCM while commanding SSA with a bidirectional scan tool. The PCM output can be checked for a varying current signal; an inverse solenoid that is commanded "pressure low" should show current near the top of its 0-1 amp range.

On the 6.0L trucks, look hard at the PCM itself. Transmission Digest documented a 2005 F-350 6.0L that set a stack of solenoid electrical codes, including P0973 and P2700, because the water-in-fuel sensor in the fuel/water separator leaked diesel onto the C138E harness. The fuel wicked up the harness into the connector and into the PCM, which held about a pint of fuel. The fix was a new PCM and water-in-fuel sensor (6C3Z-9C264-A), with the harness and C138E connector cleaned and reused. If the case connector and solenoid test fine and the truck is a 6.0L, unplug the PCM connectors and look for diesel before you condemn anything else.

The fix, by what you found

Open between pins 12 and 20: solenoid or internal harness

Drop the pan and unplug SSPC-A at the solenoid itself, then measure the solenoid terminals directly. If the solenoid reads 4.1 to 4.7 ohms on its own, the break is in the internal harness. If the solenoid reads open, replace it. ATSG notes every solenoid except PC-A can be serviced without removing the solenoid body from the case, and each is held with a large E-clip. The solenoids are keyed differently to prevent mis-assembly, but SSPC-A and SSPC-D share the inverse design and identification marks, so confirm the marks on the snout against the GEARS identification method before installing a used or loose solenoid.

Internal harness damage

Replace the harness rather than splicing inside the pan. ATSG points out a quirk worth knowing: Ford dropped the pressure switch input from the calibration before the 2003 model year went into production, so a service harness without pressure switch connectors in a solenoid body that still has the switches, or the reverse, is an acceptable repair that does not affect operation.

Solenoid good electrically but sticking

This shows up as P0751 or P0752 rather than P0750, but it is often found on the same visit. GEARS (Jarad Warren, 2017) reports that 5R110 solenoids have a habit of the valve sticking in the snout. Shake the solenoid; if the valve does not move freely, it is bad. GEARS describes cleaning them, but also warns not to touch the calibrated adjuster without a solenoid test machine. On a high-mileage unit with original solenoids, a full set is usually the better repair than one solenoid.

Reassembly and refill

• Use a new solenoid body gasket and torque the solenoid body bolts to 10 N-m (89 in-lb), following the ATSG sequence.
• Refill with MERCON LV. Ford's Motorcraft fluid chart authorizes it for the 5R110 TorqShift, including back-service on earlier trucks. A pan drop takes only part of the fill; the 2009 Super Duty owner guide lists about 17.5 qt (16.6 L) total including the cooler. Check the level hot.
• Clear codes, run a bidirectional SSA command if your tool supports it, then road test through all six gears with manual range downshifts so the PCM gets to run the coast clutch functional test in 1st and 3rd.

Keeping it from coming back

Repeat P0750s are almost always wiring: a harness that was spliced instead of replaced, a pin 20 terminal that was spread by a test probe, or contamination at the PCM on a diesel. Use the correct terminal probes at the case connector, replace the internal harness if any wire is damaged, keep the water-in-fuel sensor and fuel/water separator on the 6.0L dry, and do not reuse a solenoid body gasket. If the electrical code is fixed and the truck now sets P0751 or P0752, move on to the coast clutch itself; that is a different diagnosis.

Need parts for this job?

Our 5R110 parts page carries solenoid kits, internal harnesses, valve bodies, pumps and rebuild kits for the TorqShift, all on our own checkout.

FAQ

What does P0750 mean on a 5R110W?

P0750 is the shift solenoid A open circuit code. On the 5R110W, solenoid A is SSPC-A, the coast clutch solenoid. Ford's OBD monitor sets it when the PCM's feedback circuit shows the SSA output is open, checked continuously with battery voltage between 11.0 and 15.99 volts over a 5 second window. It is an electrical code, not a clutch performance code.

Which solenoid is shift solenoid A on a 5R110W?

It is SSPC-A, the coast clutch solenoid, mounted in the solenoid body under the pan. ATSG and Sonnax both identify it as an inversely proportional variable force solenoid, so 0 amps from the PCM gives maximum pressure to the coast clutch circuit. It shares its inverse design with the direct clutch solenoid SSPC-D.

What should SSPC-A measure in ohms?

ATSG lists 4.1 to 4.7 ohms at 72 degrees F, measured at the transmission case connector between pins 12 and 20. An open meter reading means a broken coil or a broken internal harness wire. If both pins 12-20 and 3-20 read open, look at the shared pin 20 feed and the internal harness before buying solenoids.

Is P0750 the same as P0751 or P0752?

No. P0750, P0973 and P0974 are the electrical codes for SSA: open, short to ground and short to power. P0751 and P0752 are functional codes that mean the coast clutch system tested failed off or failed on. Ford says the 5R110W cannot separate a solenoid from its clutch by ratio, so P0751 and P0752 can be a clutch, seal or solenoid valve problem.

Can I drive with a P0750?

The truck will usually move, but shift quality and engine braking are not normal, and an inverse solenoid that has lost its circuit puts full pressure on the coast clutch circuit. Short trips to the shop are fine; towing is not. Fix the circuit before it turns into a clutch or drum failure.

Related guides

• 5R110 TorqShift Shift Solenoid Symptoms, Testing and Replacement
• 5R110W P0730: Incorrect Gear Ratio Causes & Fix
• 5R110W Limp Mode Causes and Fix
• 5R110W Harsh Shift Causes and Fix
• 5R110W Valve Body Symptoms and Testing
• 5R110W P0742: TCC Stuck On Causes & Fix