P2CA3 Charge Air Cooler Coolant Pump Sense Circuit Performance

With P2CA3 the feedback signal from the intercooler pump is electrically inside its limits but does not fit what the controller expects: a reported speed or status that contradicts the command, a pulse pattern it cannot decode, or a reply that changes although the request stayed constant. Rheinmetall offers auxiliary pumps for exactly these loops that talk to the engine computer by PWM or LIN and carry extensive self-diagnosis, so the controller relies on this answer to know the loop is circulating. Contact resistance in the plug, interference on the wire, a failing pump circuit board or mismatched software in pump or engine module are possible causes. No manufacturer documents P2CA3 publicly; CARB asks for rationality checks of such inputs. Fixed high or low levels are P2CA1 and P2CA2.

Likely causes

Symptoms

• MIL on, sometimes only intermittently
• Power reduction on long climbs or in hot weather

Repair estimate

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

Parts involved

Related codes

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