Code
P08D7
Generic
P — Powertrain
Shift Solenoid K Stuck On
Views:
UK: 12
EN: 26
RU: 15
AI status
Completed
Completed
100%
Causes
- Internal short or electrical failure in solenoid K coil
- Wiring short to battery/constant power (harness damaged, pinched, or chafed)
- Poor or corroded connector or terminal at solenoid
- Failed driver transistor or output stage in TCM/PCM
- Valve body/solenoid valve mechanically stuck (debris, varnish, or worn spool)
- Contaminated or low transmission fluid causing valve sticking
Symptoms
- Malfunction Indicator Lamp (MIL) or transmission warning lamp illuminated
- Transmission stuck in one gear, harsh shifts, or delayed shifts
- Transmission in limp/safe mode (reduced functionality)
- Uncommanded engagement of clutch or gear controlled by solenoid K
- Stored transmission-related fault codes in addition to P08D7
What to check
- Read freeze frame and any additional transmission codes with a scan tool
- Check transmission fluid level and condition (contamination, burnt smell, metal particles)
- Visually inspect solenoid K connector and wiring for damage, corrosion, or pinching
- Backprobe the solenoid connector to verify command voltage/duty cycle with scan tool or multimeter
- Measure solenoid coil resistance (compare to factory spec)
- Check for unintended voltage at the solenoid with key ON, engine OFF
Signal parameters
- Command signal: ON/OFF or PWM duty cycle as requested by TCM (percent duty)
- Measured coil voltage when commanded ON (typically near battery voltage) and when OFF (should be ~0 V or open)
- Coil resistance (ohms) measured at solenoid terminals — compare to spec (typical range 6–30 Ω depending on vehicle)
- Current draw (amps) when solenoid energized — unusually high or low values indicate fault
- Continuity to ground or constant 12V when solenoid should be OFF indicates short
Diagnostic algorithm
- Connect a diagnostic scanner, read codes and freeze frame, then clear codes and attempt to re-create. Note when code returns and any related codes.
- Visually inspect the solenoid K connector and harness for damage, corrosion, loose pins, or signs of arcing. Repair as needed.
- With ignition OFF, disconnect the solenoid connector and measure coil resistance across solenoid terminals. If out of spec or shows near short/low resistance, replace solenoid.
- With connector disconnected, check for unintended voltage at the solenoid power terminal with ignition ON (engine OFF). Presence of battery voltage when circuit should be off suggests harness short to power.
- Backprobe the solenoid connector while commanding the solenoid ON/OFF using a scanner. Verify the TCM is switching the circuit and observe voltage/duty cycle. If TCM commands OFF but the circuit remains powered, suspect wiring short or internal driver failure.
- Check for short to ground/power between the solenoid circuit and other circuits (use multimeter/ohmmeter with harness disconnected). Repair wiring harness if short found.
- If wiring and solenoid check OK, perform an oscilloscope test at the TCM driver to inspect switching waveform. Abnormal waveform may indicate defective driver inside TCM.
- If electrical tests are inconclusive and symptoms persist, remove valve body (if applicable) to inspect solenoid valve for mechanical sticking, debris, or contamination. Clean or replace valve body/solenoid as required.
- After repairs, clear codes, perform self-tests and a road test to verify normal shift operation and that P08D7 does not return.
Likely causes
- Shorted wiring or pinched harness causing constant power to the solenoid
- Failed solenoid coil (internal short) causing it to remain energized
- Defective TCM/PCM output driver saturating the circuit
- Hydraulic valve stuck in the valve body due to contamination or wear
Fault status
Status
Shift Solenoid K circuit indicates solenoid remains energized (stuck ON) or circuit shows continuous power when commanded OFF. Transmission control may be degraded; repair wiring, solenoid, or controller as required.
Repair difficulty: Medium
Diagnostic time: 1.0 - 3.0 hours
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