Powertrain, generic (extended)

P2041 Reductant Injection Air Pressure Sensor A Circuit Intermittent

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2041 catches an air pressure sensor A whose signal keeps dropping out or jumping for brief moments, too short or too irregular to be confirmed as a steady low or high fault. On trucks and machines with air-assisted DEF dosing this typically comes from vibration: a terminal with lost contact tension, a cracked wire inside the loom or moisture entering the connector at the dosing module. No manufacturer documents P2041 publicly; Deutz, which uses the same sensor slot, lists only the permanent electrical faults (P2037, P2039, P2040). CARB counts erratic signals among the circuit faults an OBD system must detect. Since the fault comes and goes, wiggle-testing the harness while watching live data is more useful than measuring at rest; replacing the sensor without that test often does not help.

Likely causes

Terminal with lost contact tension at sensor or controller
Wire broken inside the insulation from vibration
Moisture in the connector

Symptoms

  • Warning lamp coming and going
  • DEF dosing interrupted at times

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–400
Time0.5–3 h

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

Parts involved

reductant air pressure sensorreductant air pressure connector

Related codes

P2037P2038P2039P2040

References: law.cornell.edu, serdia.deutz.com, energy.gov.