Powertrain, generic (extended)

P2CA1 Charge Air Cooler Coolant Pump Sense Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Some electric pumps in a water-cooled charge air cooler loop report back to the engine computer on a dedicated sense or feedback wire, kept apart from the line commanding them. P2CA1 means the level on that return wire stays above its plausible band. Usual reasons are a chafed wire touching a battery feed, a break in the line where the controller input is pulled up internally, or pump electronics that no longer switch the line at all. The title carries no pump letter. No manufacturer documents P2CA1 publicly. Pierburg's patent US8392060B2 explains that such pumps announce faults by tying a line to ground for coded periods, so a line that never drops hides every message. CARB requires circuit checks on emission-related inputs. Unable to confirm the pump, the controller may cut boost.

Likely causes

Feedback wire chafed through and touching a battery or ignition feed
Broken feedback wire or backed-out pin, input floats to its high level
Pump electronics no longer pulling the feedback line down
Damaged input stage in the engine control module

Symptoms

  • MIL on
  • Reduced power or boost under load, especially in hot weather
  • Pump fault messages from the pump no longer reach the controller

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€40–600
Time0.5–2.5 h

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

Parts involved

cac coolant pumpwiring harnessecm

Related codes

P2CA2P2CA3P023AP026EU05AA

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