P07AF

Code

Generic P — Powertrain

Transmission Friction Element G Stuck On

Brand: Generic

Type: P — Powertrain

Views: UK: 23 EN: 27 RU: 25

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Page language: EN

Causes

Failed or shorted/friction-element solenoid coil (stuck electrically on)
Valve body spool/valve stuck due to debris, varnish, or corrosion
Internal hydraulic leak or pressure bleed causing unintended engagement
Wiring harness or connector short to power (solenoid supply) or damaged ground
Faulty transmission control module (TCM) or driver transistor
Contaminated, low, or overheated transmission fluid changing hydraulic response

Symptoms

Transmission stuck in a gear or harsh/continuous engagement of a gear
Delayed or harsh shift during upshift or downshift
Reduced fuel economy and drivability issues
Check Engine/Transmission warning lamp illuminated
Locked-in limp-home mode in some cases
Unusual transmission noise or drag at idle/while coasting

What to check

Read freeze frame and live data with an advanced scanner (command/actual states, line pressure, gear)
Compare TCM command for Friction Element G vs actual engagement (where available)
Inspect transmission fluid level, color, and odor for contamination or overheating
Visually inspect wiring harness and connector for damage, corrosion, or pinched wires
Measure solenoid coil resistance and compare to manufacturer specification
Check solenoid supply voltage and ground with key on/engine off and during operation

Signal parameters

TCM command for Friction Element G (ON/OFF or duty cycle %) — should match expected values
Actual engagement flag (where provided by OEM data) vs commanded state
Solenoid coil resistance (Ω) — compare to spec; large deviation indicates coil fault
Solenoid supply voltage (≈ battery voltage with key ON) and switched voltage when commanded
Solenoid current draw (mA/A) — abnormally high suggests short/welded plunger; near zero suggests open circuit
Transmission line/regulation pressure (psi or kPa) while solenoid commanded OFF and ON

Diagnostic algorithm

Record freeze frame and full scan tool data. Note when the code sets (engine/transmission conditions).
Clear code and attempt to reproduce under the same conditions while watching live data (TCM command, solenoid status, line pressure, gear).
Check transmission fluid level, color, and smell; correct level or replace fluid if severely contaminated.
Visually inspect connectors and wiring for the Friction Element G solenoid. Repair any damaged wiring or corroded pins. Wiggle-test while monitoring live data to find intermittent faults.
With connector disconnected, measure solenoid coil resistance and compare to spec. If open/shorted or out of range, replace solenoid.
Reconnect and backprobe solenoid harness: verify supply voltage, ground, and TCM command signal (voltage/duty) while commanding solenoid via scan tool. If supply is constant battery voltage when it should be switched, trace harness for short to power.
Measure solenoid current draw while commanding OFF/ON. Excessive current with OFF indicates mechanical seizure or short. Zero/near-zero current indicates open circuit or driver fault.
If electrical tests are normal, perform hydraulic checks: measure line/regulated pressure and observe pressure change when commanding the solenoid. If pressure remains high when solenoid is commanded OFF, suspect valve body/valve stuck or internal leak.
If valve body spool is suspected, remove valve body and inspect/clean solenoids, bores, and spools for debris or wear. Replace damaged solenoid or valve body components as required.
If electrical and hydraulic subsystems test good, consider TCM driver failure. Verify TCM outputs against other solenoid outputs and consider TCM bench/test replacement as a last step.
After repair, clear codes and perform a full road test under the original conditions to verify the fault is resolved. Re-scan to confirm no other related codes.