P07AC

Code

Generic P — Powertrain

Transmission Friction Element F Performance/Stuck Off

Brand: Generic

Type: P — Powertrain

Views: UK: 23 EN: 32 RU: 31

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Page language: EN

Causes

Failed/shorted/open shift solenoid or pressure control solenoid for Friction Element F
Sticking or clogged valve in the valve body (solenoid bore or spool)
Low, contaminated, or degraded transmission fluid
Internal mechanical failure (worn clutch pack, broken return spring, stuck piston)
Damaged wiring, poor connector contacts, or corrosion to the solenoid circuit
Faulty transmission control module (TCM) or incorrect TCM software/calibration

Symptoms

Harsh, delayed, or failed shift associated with one gear range
Slipping or inability to hold gear under load
Transmission enters limp/home mode
Check Engine Light or Transmission warning lamp illuminated
Unusual transmission noise or shudder during shifting

What to check

Read and record freeze-frame and live data with a capable scan tool (solenoid command, solenoid actual/feedback, requested clutch state, transmission temperature)
Check transmission fluid level, color, and smell; note metal particles or debris in pan
Inspect transmission electrical connectors and wiring for damage, corrosion, or tightness
Scan for additional related DTCs that narrow the affected circuit or hydraulic path
Quick resistance check of the suspect solenoid(s) at the connector (compare to specification)
Visual inspection of transmission pan for excessive debris and magnet pickup

Signal parameters

Solenoid coil resistance: typically 5–30 ohms (varies by manufacturer) — compare to spec
Command signal: PWM duty cycle (0–100%) — commanded by TCM to modulate apply pressure
PWM frequency: commonly 50–300 Hz depending on vehicle (refer to service data)
Current draw while commanded: commonly 0.2–1.5 A (model dependent)
Line/actuation hydraulic pressure: target values vary by gear and manufacturer — use a pressure gauge to compare to spec (typical apply pressures 200–800 kPa / 30–120 psi)

Diagnostic algorithm

Retrieve all transmission and engine DTCs and freeze-frame data; note conditions when code set (temperature, RPM, vehicle speed, gear).
Clear codes and road-test to attempt to reproduce; monitor live data for solenoid command, actual clutch status, transmission temperature, and line pressure.
Inspect fluid level and condition; if low or contaminated, correct level and replace fluid/filter as needed before further testing.
Visually inspect wiring harness and connectors for the Friction Element F solenoid; repair any damage or corrosion. Wiggle-test harness while monitoring live data for intermittent faults.
Backprobe solenoid connector and measure resistance with ignition off; compare to spec. With ignition on, command solenoid ON/OFF and verify PWM duty/current while watching live data.
Perform a bench or direct power test of the solenoid (observe current limit and use caution) to confirm mechanical response; if solenoid is dead or draws abnormal current, replace solenoid.
If solenoid electrical tests pass but no hydraulic apply occurs, check valve body for sticking spools or debris; remove pan and valve body for inspection/cleaning if indicated.
Measure transmission line/apply pressure under commanded conditions using a calibrated gauge; compare to factory values to identify internal leakage or pressure supply issues.
If hydraulic and electrical components test good, consider TCM fault or incorrect software; check for available technical service bulletins and perform TCM reflash or replacement per manufacturer guidance.
After repairs, clear codes and re-test under the same conditions that originally set the code to confirm proper operation.