P0844 code meaning
Transmission Fluid Pressure Sensor/Switch A Circuit Intermittent
Powertrain system Generic code P08xx codes Check engine light
What P0844 means
Transmission fluid pressure sensor/switch A and B are inputs inside the automatic gearbox. A switch only reports pressure present or absent, a sensor reports a value. The letter is the maker's choice: Allison 1000 uses A and B for the switches on shift valves S1 and S2, GM's CVT for the primary and secondary pulley sensors, GM's 2025 8-speed A for the lube pressure sensor; Ford reports pressure faults under its solenoid codes instead. P0844 reports short dropouts or jumps of the signal without a lasting low or high. GM documents it in bulletin 21-NA-033 for the Corvette C8 dual clutch, together with P0841, P0846 and P0849: often a sticking valve is the cause, so the valve body is flushed and a fast learn run; if the code returns alone, the circuit is checked. Thresholds are not published.
P0844 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0844
- Warning lamp coming and going
- Occasional shift shocks
- Brief limp mode
Common causes of P0844
- Most likelyLoose contact or corrosion at the gearbox connector or control unit
- PossibleDirt in valve or sensor causing signal jumps
- PossibleSensor faulty internally
- Less likelyChafed spot in the harness
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Transmission fluid pressure sensorTransmission valve bodyTransmission wiringTransmission control module
What each part of P0844 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 8 | Area: transmission. |
| 44 | The exact fault in that area. |
What to do next
- Note P0844 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0844
What does P0844 mean?
P0844 means "Transmission Fluid Pressure Sensor/Switch A Circuit Intermittent". Transmission fluid pressure sensor/switch A and B are inputs inside the automatic gearbox. It is a generic code, so it means the same on every make.
Is it safe to drive with P0844?
Drive gently and only to a workshop. With P0844 the car can go into limp mode (reduced power) to protect itself.
Will P0844 fail an emissions test?
Yes, it can. P0844 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0844 to fix?
Difficulty: medium. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P0844 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.