P2758

Code

Generic P — Powertrain

Torque Converter Clutch Pressure Control Solenoid Control Circuit Stuck On

Brand: Generic

Type: P — Powertrain

Views: UK: 22 EN: 46 RU: 28

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Page language: EN

Causes

Short to battery (power) on the TCC solenoid control circuit
Stuck or internally shorted TCC pressure control solenoid
PCM/TCM driver transistor failure
Faulty connector, corrosion, or poor pin contact
Damaged wiring harness (chafed wire, pinched, water intrusion)
Failed transmission control valve or internal hydraulic fault forcing pressure

Symptoms

MIL (check engine light) illuminated
Transmission may feel locked or harshly engaged at low speeds or during decel
Poor idle or stalling when TCC locks incorrectly
Reduced fuel economy
Transmission slipping, shudder, or abnormal shift behavior
Possible limp-in mode or reduced performance

What to check

Scan for P2758 and related codes; record freeze-frame data and pending codes
Check live data for TCC commanded state vs actual TCC percent/duty
Inspect transmission fluid level, color, and smell; check for contamination
Visual inspection of TCC solenoid connector and wiring for damage or corrosion
Backprobe connector to measure control voltage and ground with key ON and during engine run
Measure DC resistance of TCC pressure control solenoid with harness disconnected

Signal parameters

Typical DC resistance of TCC solenoids: ~5–40 ohms (varies by vehicle) — consult OEM spec
Control signal: PWM duty cycle 0–100% (varies by design) when commanded ON
Control voltage: 0–12 V range depending on driver design (ground-switched or supply-switched)
Typical PWM frequency range: ~50–250 Hz (vehicle-specific)
On-state: solenoid circuit sees supply or ground depending on driver topology; voltage should change when PCM commands ON/OFF

Diagnostic algorithm

Retrieve codes, freeze-frame and live data. Confirm P2758 presence and note conditions when set (temp, gear, speed, load).
Visually inspect TCC solenoid connector and wiring for corrosion, damaged insulation, or fluid intrusion. Repair as needed.
With ignition OFF, disconnect the TCC solenoid connector. Measure the solenoid coil resistance between its terminals and compare to OEM range. If coil is shorted/opens, replace solenoid.
With harness disconnected, check for unintended battery voltage or a short to ground on the control circuit using a multimeter. There should be no constant battery voltage present on the control lead when the PCM is commanding OFF.
Reconnect and backprobe the connector. With ignition ON and engine off, command TCC ON/OFF (if possible) and observe voltage/duty at the PCM side. Verify PCM changes output and the harness follows. If PCM output is stuck ON but harness shows correct behavior when disconnected, suspect PCM.
Wiggle-test harness while monitoring live data to identify intermittent wiring faults.
Use an oscilloscope to inspect the waveform from the PCM to the solenoid to confirm proper PWM frequency and clean switching. Look for stuck-high or stuck-low states, excessive noise, or missing transitions.
If electrical checks pass and solenoid operates electrically but TCC still locks, inspect valve body and hydraulic circuits for stuck valves or internal leakage that can hold pressure. Check fluid level/condition; perform transmission pressure tests per OEM procedure.
Repair or replace faulty wiring, connector, solenoid, or valve body components as identified. If PCM/TCM output driver is suspected after verifying harness and solenoid, replace or reprogram module per OEM guidance.
Clear codes and perform a road test to confirm repair. Re-scan to ensure code does not return.

Likely causes

Shorted wiring to battery (most common when circuit reads 'stuck ON')
Failed/shorted solenoid coil
Corroded connector or poor ground causing false ON reading
PCM/TCM output driver failure (less common)

Fault status

⚠️ Status

P2758 — Torque Converter Clutch Pressure Control Solenoid Control Circuit Stuck ON: PCM detects control circuit energized when it should be off. Investigate wiring, solenoid, and control module.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-3.5 hours