The gears inside of an automatic transmission are changed with hydraulic pressure, which is maintained by little electromechanical devices known as pressure control solenoids. If the ECU detects that its range of movement or performance does not meet with known parameters, a P2728 DTC will be stored in the ECU memory.
What Transmission Do I Have?
How Serious is the Code?
The P2728 diagnostic trouble code is actually one of the more serious OBDII trouble codes, because it has to do with one of the devices responsible for maintaining the hydraulic pressure necessary to operate a particular gear or clutch pack. If one of the pressure control solenoids is not performing correctly, then you can experience a number of transmission problems including slipping, delayed gear changes and engine stalling.
Symptoms
Symptoms of a P2728 include:
- Erratic shifting
- Delayed or harsh shifts
- Transmission slipping
- Engine stalls when coming to a stop
- Transmission gets stuck in a gear
- Vehicle won’t move when in gear
- Lower MPG
- Transmission overheats
- Limp mode
Causes
- Dirty transmission fluid / filter
- Not enough transmission fluid
- Damaged wiring/connectors
- Malfunctioning pressure control solenoid
- Defective transmission pump
- Blocked pressure passage
- Valve body issue
- TCM or ECU failure
How to Diagnose the Code?
Since a P2728 DTC has to do with controlling the transmission fluid, the level and condition of said fluid needs to be checked. Dirty transmission fluid can cause a number of transmission problems, including a poor performing pressure control solenoid. If there is nothing wrong with the transmission fluid, then the wiring and connectors on the transmission wiring harness need to be checked. If no broken wires/connectors are found, then the pressure control solenoid itself will need to be tested. The valve body and transmission pump may also need to be checked, along with the ECU/TCM.
What Transmission Do I Have?
What Repairs Will Fix P2728?
- Changing the fluid and filter
- Replace faulty pressure control solenoid
- Repair or replace a faulty transmission pump
- Repair or replace transmission valve body
- Perform transmission flush to clean passages
- Cleaning corrosion from connectors
- Repairing or replacing wiring
- Flashing or replacing PCM
Related Codes
- P2722 – Pressure Control Solenoid E
- P2723 – Pressure Control Solenoid E Perf or Stuck Off
- P2724 – Pressure Control Solenoid E Stuck On
- P2725 – Pressure Control Solenoid E Electrical
- P2726 – Pressure Control Solenoid E Intermittent
- P2727 – Pressure Control Solenoid E Ctrl Circ / Open
- P2729 – Pressure Control Solenoid E Ctrl Circ Low
- P2730 – Pressure Control Solenoid E Ctrl Circ High
