P2729 indicates that the engine/powertrain control module has detected an abnormally low voltage or resistance condition on the electrical control circuit for automatic transmission pressure control solenoid “E.” This is an electrical circuit fault, meaning the solenoid coil, its wiring, or the control output is pulling the circuit lower than the PCM expects.
The solenoid coil can develop an internal short-to-ground or open circuit, causing the control circuit voltage to read low and setting the code.
The solenoid control wire may be chafed, pinched, or rubbed through, creating a path to ground before reaching the PCM.
Corroded, bent, loose, or oil-contaminated pins at the transmission harness connector or solenoid connector can raise resistance or create a false low-circuit reading.
A broken wire, damaged splice, or failing internal transmission harness can reduce current flow and make the PCM register the circuit as low.
Rarely, the PCM’s low-side driver for the solenoid can fail and keep the circuit low; this should only be considered after the solenoid and wiring have been ruled out.
You can usually drive briefly, but shifting may be harsh or the transmission may enter limp mode. Continued driving can stress internal clutches, so it should be diagnosed promptly.
No. Wiring shorts, connector problems, and internal harness faults are very common, so the circuit should be tested before replacing the solenoid.
Usually not. PCM driver failure is uncommon for this code; most failures are the solenoid itself or the wiring/connectors. Only consider the PCM after electrical testing rules those out.
No. P2729 is an electrical control-circuit fault. Low or dirty fluid can cause shift quality problems, but it will not directly set this circuit-low code.