P0844 OBD-II Trouble Code: Transmission Fluid Pressure Sensor/Switch A Circuit Intermittent

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0844 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0844 code

P0844 is a diagnostic trouble code (DTC) for "Transmission Fluid Pressure Sensor/Switch A Circuit Intermittent". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P0844 DIAGNOSTIC Get a fair and transparent estimate upfront

diagnostic check engine light

P0844 code definition

The storage of a P0844 trouble code means that the Powertrain Control Module (PCM) has detected a deviation in the voltage signal received from the transmission fluid pressure sensor circuit. Some related codes include P0840, P0841, P0842, P0843, P0845, P0846, P0847, P0848, and P0849.

What the P0844 code means

The PCM uses data from the transmission fluid pressure sensor/switch to determine if the right amount of pressure is present for proper vehicle operation. When the pump pressure varies from what is needed, a P0844 trouble code is stored and the Check Engine light illuminates.

What causes the P0844 code?

A faulty electronic pressure control solenoid, blockage within the fluid passages of the transmission, a bad transmission fluid pressure sensor, a low fluid condition, dirty transmission fluid, a mechanical failure of the transmission, or even a faulty PCM or Transmission Control Module (TCM) are some common causes for the storage of a P0844 trouble code.

What are the symptoms of the P0844 code?

The symptoms of a P0844 trouble code range from no obvious signs to the inability to shift properly, and even a failure of the torque converter to work properly. Some other common symptoms of a P0844 trouble code include difficulty in shifting, transmission overheating, and a reduction in the vehicle's fuel efficiency. Also, when this code is stored, some PCMs can place the vehicle transmission into Limp-in mode.

How does a mechanic diagnose the P0844 code?

Mechanics need an advanced scanner, digital volt/ohmmeter, manual pressure gauge, a hydraulic pressure diagram, and a manufacturer's wiring diagram to properly diagnose a P0844 trouble code. In addition to this equipment, the mechanic should perform the following steps:

  • Inspect the wiring, connectors, and components associated with the transmission, looking for any that have corrosion or damage.
  • The mechanic should also check the transmission fluid, looking for a burnt smell or that looks abnormal in any way.
  • If this is the case, the mechanic should pull the transmission pan and look for any signs of debris, such as from the clutch. This is an indicator that the transmission needs rebuilding and the torque converter replaced.
  • Once fixed, the mechanic should fill the transmission fluid to a level to allow for repair of any leaks.
  • After all leaks are fixed, the mechanic should fill the transmission fluid to an appropriate level. The mechanic should then clear the code, start the car, and allow it to reach a normal operating temperature.
  • Test drive the vehicle to see if the transmission works smoothly and if the trouble code returns.
  • If the trouble code returns, hook the scanner to the diagnostic connector and download any stored trouble codes, as well as the freeze frame data.
  • Hook a manual pressure pump to the transmission to check the pressure of the hydraulic pump. The mechanic should use a hydraulic pressure diagram while doing so, comparing their findings with the manufacturer's specifications. The mechanic should also test the electronic pressure regulator at this time.
  • Test the torque converter to see if it has gone bad.
  • If the code returns after clearing it, the mechanic should use a digital volt/ohmmeter to check the reference voltage and ground signal of the transmission fluid pressure sensor, electronic pressure control solenoid, and all related circuits. If the voltage or ground are open, test the circuits for resistance and continuity. The mechanic should first disconnect all related control modules though to prevent controller damage.
  • Clear the code to see if it returns. If it does, check the PCM to see if it has gone bad.
  • Clear the codes once again, and re-test the system to see if the code persists.

Common mistakes when diagnosing the P0844 code

Often, mechanics erroneously replace a high pressure pump in response to this code when the problem actually lies with the transmission pressure sensor, electronic pressure control solenoid, or faulty wiring. This misdiagnosis of the problem usually results in the code returning.

How serious is the P0844 code?

The seriousness of a P0844 trouble code can range from not serious at all to an inoperable vehicle that fails to shift properly, if at all. A driver of a vehicle that has a stored P0844 trouble code should have the problem diagnosed and fixed as soon as possible to avoid any potential issues.

What repairs can fix the P0844 code?

To repair a P0844 trouble code, the mechanic should do the following:

  • Replace any faulty or damaged wiring, connectors, or components.
  • Rebuild the transmission if it was damaged due to a low fluid condition. The mechanic should also install a new torque converter when rebuilding the transmission.
  • Repair any leaks detected in the transmission.
  • Replace the hydraulic pump. The mechanic should keep in mind that this process requires the removal and partial disassembly of the transmission, so they should plan accordingly.
  • Replace the torque converter if found to be faulty.
  • Replace the transmission fluid pressure sensor, electronic pressure regulator, or electronic pressure control solenoid if faulty.
  • Replace the PCM if bad. The mechanic should keep in mind that PCM failure is rare and the component should only be replaced after everything else has checked out. PCM replacement also requires the mechanic to reprogram it.

Need help with a P0844 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

trouble codes
P0844
OBD-II

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0844 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

3,484

Rating Summary
3,176
153
40
23
92
3,176
153
40
23
92

Richard

10 years of experience
415 reviews
Richard
10 years of experience
This is the second time I’ve had Richard work on my car. He always does an outstanding job and is quick, knowledgeable and professional. Highly recommended!!
2012 DODGE CHALLENGER - CHECK ENGINE LIGHT IS ON - LAS VEGAS, NEVADA

Michael

13 years of experience
372 reviews
Michael
13 years of experience
Mike was an absolute professional when he arrived. He walked me thru the whole process of my repairs and also made good recommendations for preventive issues. His mechanical knowledge and good customer services was a breath of air and greatly appreciated :-)
2007 CHEVROLET AVALANCHE - CHECK ENGINE LIGHT IS ON INSPECTION - MARIETTA, GEORGIA

Rodrigo

10 years of experience
85 reviews
Rodrigo
10 years of experience
Rodrigo was exactly on time, very professional and friendly. He assessed my car, let me know the exact problem when a previous mechanic from a shop in my area was unable to. I felt he was very honest and sincere letting me know the level of urgency that I deal with the issue. Absolutely no pressure. I will absolutely use Rodrigo the next time I need anything to do with my car and will tell everyone about him. This is such a great service, I will never go to another mechanic again. It is so convenient. I couldn’t be happier. :)
2013 SMART FORTWO - CHECK ENGINE LIGHT IS ON - LAS VEGAS, NEVADA

Ricardo

8 years of experience
223 reviews
Ricardo
8 years of experience
Great service and was very helpful on what maintenance my vehicle needed and what to expect in the future. Would definitely recommend to anyone and will.
2004 MITSUBISHI LANCER - CHECK ENGINE LIGHT IS ON - LOS ANGELES, CALIFORNIA

More related articles

How to Find the Keyless Code on a Ford Explorer or Mercury Mountaineer
Many Ford Explorers and Mercury Mountaineers were manufactured with an option known as the Ford keyless entry keypad. Some models refer to it as SecuriCode as well. It...
The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Shutterstock.com Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....
Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...

Related questions

Q: I have a 2012 cc with a p0016 code no start. chain is tight and all turns freely when turned by hand

Code P0016 broadly means that the PCM has detected that the Crankshaft and Camshaft are out of sync. If they are out of sync beyond a specific, threshold number of degrees, the car simply won't start. The cause of that...

Q: Looking for info about most common OBD2 Codes

There are two (at least) quite distinct issues in regard to your general request: The first is, once a check engine light illuminates, what are the most "frequent" codes that are stored and thence downloaded, that is what does THAT...

Q: How to diagnose coded p0352,0352,0353, already had new plugs and coils before code throw

Hello. The codes listed are for problems with the electrical circuits of ignition coils A, B, and C. If the coils have been replaced it may be possible that the wiring to them is the source of the issue. You...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com