Powertrain, generic (extended)

P2D08 Motor Electronics Coolant Pump B Supply Voltage Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2D08 watches the line that actually powers motor electronics coolant pump B, typically a fused 12 V feed plus ground: the voltage there is too low, too high or absent. The control-line faults of the same pump have their own codes, P0B38 to P0B3A, so P2D08 sends the search to fuses, relays, splices and the ground point rather than to the signal wire. Because many modules share the 12 V net, look for other low-voltage codes and check the auxiliary battery and DC/DC converter first. No manufacturer publicly documents P2D08. Ford's 2024 summary shows the same fault type (1C, supply voltage out of range) for its auxiliary pumps, with a 5 s check enabled from 11 V; the 2020 Ford hybrids carry the pump A version, P2D03. Pump B then fails to cool its electronics and power may be reduced.

Likely causes

Corroded connector, loose terminal or poor ground at pump B
Blown fuse or faulty relay in the pump B feed
Weak 12 V battery or DC/DC converter delivering too little voltage
Chafed supply wire with intermittent contact

Symptoms

  • Warning lamp on
  • Pump B works only intermittently
  • Additional voltage codes in neighbouring modules

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–600
Time0.4–2.5 h

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

Parts involved

motor electronics coolant pump bpower electronics coolant loop

Related codes

P2D09P2D05P2D03P2D0DP0B38

References: fordservicecontent.com, static.nhtsa.gov, law.cornell.edu.