P27C2

Code

Generic P — Powertrain

Pressure Control Solenoid P Stuck On

Brand: Generic

Type: P — Powertrain

Views: UK: 22 EN: 32 RU: 19

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Causes

Short to battery/constant 12V on the solenoid circuit
Failed/shorted pressure control solenoid P
Open or damaged ground for the solenoid circuit
Corroded/loose connector or wiring harness damage
Valve body hydraulic fault causing the solenoid to be held on mechanically
Faulty transmission control module (TCM) or software error

Symptoms

Transmission stuck in a gear or fails to shift properly
Harsh or delayed shifts, slipping, or abnormal shift timing
Transmission goes into limp/limitation mode and MIL/TCM warning light may be on
Unusual transmission noise or shuttle hesitation
Reduced drivability and possible reduced fuel economy

What to check

Read and record all stored codes and freeze-frame data with a capable scan tool
Check battery voltage and charging system (low battery can cause false faults)
Inspect fuses and relays related to transmission/TCM circuits
Visually inspect the solenoid connector and wiring harness for corrosion, pin damage, chafing, or melted insulation
Backprobe the solenoid connector with ignition ON (engine off) to verify reference voltage and ground
Measure solenoid coil resistance at the connector (with harness disconnected)

Signal parameters

Nominal solenoid coil resistance: typically 10–40 ohms (manufacturer-specific)
Supply voltage (key ON): near battery voltage ~11–14 V to the feed circuit
ECU/TCM output: typically a PWM ground-side driver — duty cycle 0–100% when commanded
PWM frequency range commonly 50–300 Hz (vehicle-specific)
When not commanded: voltage at solenoid connector should be ~battery voltage on feed and open/high impedance on driver side (no continuity to ground)

Diagnostic algorithm

Retrieve code(s) and freeze frame; note conditions when fault set (temp, vehicle speed, gear).
Visually inspect solenoid connector and harness for damage, corrosion, or pin push-out. Repair any obvious damage before further testing.
Check related fuses and relays. Replace if blown or faulty.
With harness connected and ignition ON (engine OFF), backprobe the solenoid connector: verify feed voltage (~battery) and driver state. With solenoid NOT commanded, driver side should be open/high impedance. If driver side is grounded/low, suspect short to ground or stuck driver.
Measure solenoid coil resistance with harness disconnected and compare to spec. Very low or infinite resistance indicates solenoid fault.
Command the solenoid ON/OFF using a scan tool active test while monitoring voltage and current at the solenoid. Confirm that the driver switches (PWM to ground) and observe duty cycle and current draw. If the driver remains ON when commanded OFF, suspect wiring short-to-voltage or TCM output stuck ON.
Perform a bench test: briefly apply 12 V to the solenoid (observing polarity and safe procedure) to confirm mechanical operation. Do not apply continuously or without current limiting unless specified.
If solenoid passes and wiring is intact but output remains active, inspect TCM grounds and power supply. If TCM output stage is suspected, consider TCM repair/reprogramming/replacement per manufacturer guidance.
If electrical system checks OK but symptoms persist, remove and inspect valve body for hydraulic blockage or valve sticking that could mimic a stuck solenoid function.
After repairs, clear codes and perform a road test under conditions similar to when the code set to confirm repair.