P27D7

Code

Generic P — Powertrain

Pressure Control Solenoid S Control Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 29 EN: 38 RU: 26

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Page language: EN

Causes

Open or high-resistance wiring in the solenoid control circuit
Short to ground on the solenoid control conductor
Corroded or loose connector or terminal at the solenoid or TCM/ECM
Failed pressure control solenoid (coil shorted or open)
Blown fuse or loss of power/ignition feed to circuit
Poor or missing ground at transmission or control module

Symptoms

Transmission may go into limp/diagnostic mode
Harsh, delayed, or stuck shifts
Erratic line/pressure control and poor shift quality
Transmission fault or check engine/ MIL illumination
Possible inability to shift into certain gears

What to check

Read and record freeze-frame and live data with a capable scan tool; note related codes
Verify battery voltage and charging system health before tests
Visually inspect solenoid connector and wiring for corrosion, damage, or separation
Back-probe the connector and measure voltage at the control pin with key ON and during commanded events
Measure coil resistance (with harness disconnected) and compare to specification or typical range
Perform continuity and short-to-ground checks between solenoid pin and TCM/ECM driver pin

Signal parameters

Control signal type: PWM (pulse-width modulated) command from TCM/ECM; duty 0–100% depending on commanded pressure
Typical command voltage: switched between near-battery voltage and ground; voltage when commanded ON will vary with PCM strategy
Typical PWM frequency range (generic): ~50–300 Hz (vehicle-specific — consult service manual)
Coil resistance (typical generic range): ~5–40 ohms (measure and compare to vehicle spec)
Low-circuit fault indication: driver output voltage significantly below expected when commanded (e.g., near 0–1 V) or open circuit reading

Diagnostic algorithm

Connect a scan tool, read codes and freeze-frame data. Note any related transmission or powertrain codes.
Verify battery voltage is within normal range (12.4–14.8 V) before electrical testing; low supply can produce false results.
Visually inspect the solenoid connector and wiring harness for damage, corrosion, pins pushed out, or water intrusion.
With ignition OFF, disconnect solenoid connector and measure coil resistance across the solenoid terminals. Compare to spec or typical range.
Check for short to ground: with connector disconnected, measure resistance from the control wire to chassis ground. Very low resistance indicates a short.
With ignition ON (engine off) back-probe the control wire at the connector and command the solenoid ON using the scan tool. Observe voltage behavior (should show commanded PWM or switching and not remain low).
Wiggle wiring and connectors while monitoring the control signal and live data to locate intermittent faults.
If wiring and connector test good but solenoid shows abnormal resistance or does not react when directly energized, replace the solenoid.
If solenoid and wiring test good but control output remains low, suspect TCM/ECM driver fault — verify by checking module outputs or substituting a known-good module where practical and safe.
After repair, clear codes and perform a road test with live data to confirm proper operation and no return of the code.

Likely causes

Damaged or corroded connector at solenoid
Open or shorted wiring harness to solenoid
Failed solenoid coil
Poor ground or low battery/ignition supply voltage
Module driver failure (less common)

Fault status

⚠️ Status

P27D7 — Pressure Control Solenoid S Control Circuit Low. TCM/ECM reports lower-than-expected voltage on the solenoid control circuit. Inspect wiring, connector, supply/ground, solenoid, and module driver.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours