P2041: Reductant Injection Air Pressure Sensor A Circuit Intermittent

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.

Symptoms

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

Most likely causes

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

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the AdBlue/DEF level and quality, and do not add additives or water
2. Gently move the wiring with the engine running and watch whether the reading changes.
3. Look for white crystals around the injector and the tank
4. Check connectors and heaters with the scanner
5. Run the dosing test available on your diagnostic tool
6. Replace parts only when the test points to that component

Good to know

• Repair difficulty: medium
• It affects emissions.

What each character of P2041 means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 0: Subsystem depends on the code range
• 41: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2041?

Deal with it soon. If the instrument cluster shows a countdown, the car may not restart once it reaches zero.

What causes code P2041?

The most common causes are: terminal with lost contact tension at sensor or controller; wire broken inside the insulation from vibration; moisture in the connector.

Related codes

• P2037Reductant Injection Air Pressure Sensor A Circuit
• P2038Reductant Injection Air Pressure Sensor A Circuit Range/Performance
• P2039Reductant Injection Air Pressure Sensor A Circuit Low
• P2040Reductant Injection Air Pressure Sensor A Circuit High

Sources

• law.cornell.edu: 13 CCR 1968.2
• serdia.deutz.com: DTCList EMRL1 SecondaryECU EN
• energy.gov: 2005 deer hesser

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.