Powertrain, generic (extended)

P2DD9 EVAP System Leak Detection Pump Control Circuit Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2DD9 means the drive circuit of the evaporative leak detection pump is electrically intact, yet the pump does not react the way the command implies: the feedback the engine computer reads back, usually motor current or driver state, does not match the on or off request. Bosch-style DM-TL pumps on European cars are judged by their motor current, first while blowing through a 0.5 mm (0.020 in) reference orifice and then against the closed tank, so a sluggish motor or a resistive plug skews the entire leak test. CARB wants EVAP parts checked for proper functional response as well as for opens and shorts. GM's 2025 tables suspend their pump tests while a pump circuit fault is active. No maker documents P2DD9 publicly; plain circuit faults are P2400 to P2402. Driving is unaffected, only the leak check is lost.

Likely causes

Pump motor worn or sluggish, current draw off target
Corroded connector or chafed wire adding resistance in the pump feed
Water or ice in the pump module (mounted near the wheel arch)
Faulty output stage or current sensing in the engine control module

Symptoms

  • Check engine light on
  • EVAP readiness monitor stays incomplete
  • No noticeable change in driving

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–450
Time0.5–2 h

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

Parts involved

evap leak detection pumpwiring harnessecm

Related codes

P2400P2401P2402P2404P2DDAP2DDB

References: law.cornell.edu, vehicleservicepros.com, gsi.ext.gm.com.