Every modern automatic transmission uses little spring-loaded plungers called pressure control solenoids, to maintain the hydraulic pressure necessary to move clutch packs and other components. If the ECU detects a low voltage situation with one of the pressure control solenoids, it won’t be able to control the solenoid properly, which will trigger a P2729 DTC.
How Serious is the Code?
Having a P2729 diagnostic trouble code is pretty serious, as the underlying problem with the pressure control solenoid can affect the drivability and safety of your vehicle. Some of the transmission problems that you can expect include delayed shifts, harsh shifts, limp mode and engine stalling
Symptoms of a P2729 include:
- Harsh, erratic shifts
- Engine stalls while stopped in gear
- Vehicle won’t move when in gear
- Increased fuel consumption
- Transmission overheats
- Limp mode
- Insufficient transmission fluid
- Dirty transmission fluid / filter
- Frayed wiring / damaged connectors
- Failing pressure control solenoid
- Failing transmission pump
- Internal pressure problems
- Valve body issue
- ECU or TCM failure
How to Diagnose the Code?
Transmission fluid is extremely important to the operation of your gearbox, and dirty or low transmission fluid can actually cause the pressure control solenoids not work correctly. So the transmission fluid is the first thing that should be checked when diagnosing a P2729 OBDII trouble code. The next thing that should be considered is the condition of the wiring and connectors on the transmission wiring harness. If no loose wires or broken/corroded connector pins are found, then the pressure control solenoid itself will have to be tested. Other potential causes for this problem include the valve body, transmission pump and ECU/TCM.
What Repairs Will Fix P2729?
- Changing the fluid and filter
- Replace faulty pressure control solenoid
- Repair or replace a faulty transmission pump
- Repair or replace defective transmission valve body
- Transmission flush to clean passages
- Cleaning corrosion from connectors
- Repairing or replacing wiring
- Flashing or replacing PCM
- 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
- P2728 – Pressure Control Solenoid E Ctrl Circ Range/Perf
- P2730 – Pressure Control Solenoid E Ctrl Circ High