Code
P08C2
Generic
P — Powertrain
Pressure Control Solenoid L Control Circuit High
Views:
UK: 18
EN: 26
RU: 23
AI status
Completed
Completed
100%
Causes
- Open or short to voltage in the solenoid control wiring
- Faulty pressure control solenoid L (internal shorted coil or internal fault)
- Poor connector contact or corroded terminal at solenoid or PCM/TCM
- PCM/TCM driver transistor fault
- Aftermarket wiring or recent repair damaged the harness
- Intermittent wiring fault (chafing, water ingress)
Symptoms
- Malfunction Indicator Lamp (MIL) or transmission warning lamp illuminated
- Hard, delayed, or incorrect gear shifts
- Transmission in fail-safe/limp mode with limited gear range
- Transmission slipping or harsh engagement
- Stored freeze frame data and related transmission codes
What to check
- Read freeze frame and stored codes with a capable scan tool; attempt active/tests on solenoid if available
- Visual inspection of solenoid connector and wiring for corrosion, damage, pin push-out, or aftermarket splices
- Backprobe connector and measure DC voltage and signal behavior with ignition on and during commanded changes
- Measure solenoid coil resistance with connector disconnected (compare to spec)
- Check continuity between solenoid connector and PCM/TCM pin; check for short to battery and short to ground
- Use an oscilloscope to verify PWM waveform and duty cycle if available
Signal parameters
- Control type: typically PCM/TCM-driven PWM to modulate pressure (duty cycle control)
- Expected control voltage range: controller switches between near 0 V and battery voltage (~12 V) depending on strategy
- Typical coil resistance (varies by vehicle): commonly tens of ohms (e.g., ~10–60 Ω). Check OEM spec for exact value
- PWM frequency: commonly from a few dozen to several hundred Hz (vehicle-specific)
- Fault condition: measured control circuit voltage higher than expected or above PCM threshold for a valid signal
Diagnostic algorithm
- Retrieve and record all related codes and freeze frame data. Note conditions when code set.
- Clear codes and perform a short test drive to verify repeatability.
- Perform a careful visual inspection of wiring and connector at the solenoid and along wiring route to PCM/TCM. Repair any obvious damage.
- With ignition off, disconnect solenoid connector and measure coil resistance between the solenoid terminals. Compare to OEM specification. Replace solenoid if resistance is out of range or shows open/short to ground.
- Check for continuity between the PCM/TCM control pin and the solenoid connector. Verify there is no short to battery voltage or to ground.
- With connector connected and back-probing, measure DC voltage at the control pin with ignition on (engine off). Command the solenoid ON/OFF with a scan tool while observing voltage. Look for stuck-high voltage or lack of switching.
- If available, use a lab scope to view the PWM waveform while commanding the solenoid. Note duty cycle changes and any abnormal voltage spikes or noise.
- If wiring and solenoid check good but circuit remains high, suspect PCM/TCM output driver fault. Confirm with manufacturer diagnostic procedures; replacement usually required only after all wiring and solenoid checks done.
- After repairs, clear codes and verify proper operation on test drive. Re-check for leaks or other mechanical issues that might mask symptoms.
Likely causes
- Damaged wiring harness near transmission (short to battery voltage)
- Corroded or pushed-out terminal at solenoid connector
- Faulty solenoid causing abnormal voltage behavior
- PCM/TCM output transistor failed (less common)
Fault status
Status
PCM detected high voltage or abnormal high-level signal on Pressure Control Solenoid L control circuit. PCM may set limp mode or alter transmission pressure strategy to protect drivetrain.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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