P0929

Code

Generic P — Powertrain

Gear Shift Lock Solenoid/Actuator Control Circuit A Range/Performance

Brand: Generic

Type: P — Powertrain

Views: UK: 24 EN: 74 RU: 36

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Open, short, or high-resistance wiring in the shift-lock solenoid control or return circuit
Corroded, loose, or damaged connector at the solenoid or TCM
Failed gear shift lock solenoid/actuator (coil open/short, mechanically stuck)
Blown fuse, relay, or inadequate supply voltage to the circuit
Faulty TCM or internal driver transistor
Mechanical binding in the shift-lock mechanism or actuator linkage

Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
Key/starter interlock or shift interlock may not release (cannot shift out of Park)
Intermittent or no operation of shift-lock mechanism
Transmission shift-related warnings or limp-home behavior
Stored transmission-related trouble codes

Read and record freeze-frame data and all stored codes with a scan tool; check for related transmission codes
Verify battery voltage and charging system condition (stable 12–14.5 V with key on/cranking)
Inspect fuses and relays for the transmission/shift-lock circuit
Visually inspect connectors and wiring for corrosion, damaged insulation, pin push-out, or water intrusion
Backprobe the solenoid connector and monitor voltage/ground while commanding the solenoid with a scan tool
Measure solenoid coil resistance with a multimeter (compare to service specification or typical range)

Control signal: On/off or PWM from TCM when commanded (duty cycle varies by design)
Supply voltage (key ON): ~12 V nominal at fuse/solenoid supply (should not drop significantly when commanded)
Solenoid coil resistance: typically low-ohm range (example 5–100 Ω depending on design) — consult vehicle spec
Circuit continuity: near 0 Ω to ground when expected; no open circuits
Current draw when energized: measurable and within expected range (no excessive current suggesting short, no open/infinite suggesting open coil)

Confirm code and scan for related codes; review freeze-frame and any transmission status data.
Verify battery state and test fuses/relays that feed the shift-lock circuit; replace any blown fuses.
Visually inspect the solenoid/actuator connector and wiring harness for damage, corrosion, or loose pins; repair as needed.
With connector accessible, backprobe the solenoid connector. Command the shift-lock solenoid ON/OFF with a scan tool and observe voltage/ground behavior.
Measure the solenoid coil resistance with the connector disconnected. Compare to specification or typical expected range. If open/shorted, replace the solenoid.
Apply specified nominal voltage to the solenoid (bench test) to verify mechanical operation. Do not exceed vehicle nominal voltage and follow safe bench-testing practices.
Check for intermittent faults: wiggle harness and connectors while commanding the solenoid and monitoring signal/current. Repair or replace damaged wiring/connector.
If wiring and solenoid check good, verify TCM output with an oscilloscope or a known-good module diagnostic procedure. Replace or reprogram TCM only after confirming the driver output is faulty and no wiring/ground issue exists.
After repairs, clear codes, test operation in multiple conditions (key positions, cranking, shift attempts), and perform a road/test drive if applicable to confirm resolution.