Powertrain, generic · Transmission

P088E Planetary Gear Set Failure

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

P088E means the module has found that a planetary gear set no longer keeps the fixed speed relation between its sun, carrier and ring gear, for example through broken planet gears, seized planet pins or stripped teeth. No maker's table or bulletin documents the code. It suits power-split hybrid transmissions, which measure speeds at several members: a Toyota patent compares the road speed calculated from engine, generator speed and planetary ratio with the measured one, flags a deviation of about 10 km/h for about 1 s and then drives electrically only. In stepped automatics such damage usually shows as ratio or slip codes.

Likely causes

Planet gears or pins seized or broken (lubrication, overheating)
Tooth damage on sun or ring gear
Speed sensor (engine, motor-generator, output) reading wrong
Low or worn fluid

Symptoms

  • Grinding or whining from the gearbox
  • Power loss, limp mode (hybrids drive electrically only)
  • Possibly no drive

Repair estimate

DifficultyHardWorkshop job
Parts and labour€1,500–6,000
Time6–15 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

planetary gear settransmissionspeed sensortransmission control module

Related codes

P0894P0729P0730P0893P0720P0715

References: law.cornell.edu, patents.google.com.