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1999 BMW 540IT E39
4.4L V8•RWD•AUTOMATIC•gas
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Repairs0Labor496Torque2399Fluid8DTC1210Battery1Maintenance0Recalls0
P1755moderate severityPowertrain

Torque Converter Lock-Up Solenoid Circuit

on 1999 BMW 540iT E39 4.4L V8 · RWD

What this code means

The DME or EGS detected a malfunction in the torque converter lock-up solenoid circuit. The solenoid controls engagement of the torque converter clutch for improved fuel efficiency at highway speeds.

Symptoms

  • Check Engine Light
  • No torque converter lock-up
  • Reduced fuel economy on highway
  • Transmission overheating
  • Slight RPM flare at cruise

Common causes

  • Faulty torque converter clutch solenoid
  • Wiring fault in solenoid circuit
  • Connector corrosion
  • Low transmission fluid level
  • EGS driver circuit failure

Diagnostic steps

  1. Test TCC solenoid resistance
  2. Inspect wiring to solenoid
  3. Check transmission fluid level and condition
  4. Monitor TCC commanded vs actual engagement
  5. Check connector at transmission

Repair notes

Replace the torque converter lock-up solenoid or repair the wiring fault.

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