P2037Reductant Injection Air Pressure Sensor A Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Some heavy-duty SCR systems do not spray DEF on their own pressure alone but blow it into the exhaust with compressed air, supplied by a compressor or an existing air system; Bosch's first Denoxtronic generation was built this way. A pressure sensor checks that this air is present before dosing. P2037 is the general circuit fault of that sensor. Deutz uses it on the EMR L1 controller (SPN 4335) for two failure types: a ground fault (-F0) and a sensor supply out of range (-1C), while a reading stuck low or open goes to P2039 and a short to battery to P2040. CARB names air assisted injection as part of the reductant delivery that must be monitored. With the air pressure unknown, dosing is normally stopped, and on trucks a power derate may follow.
- What you may notice
- Engine or emission warning lamp on
- DEF dosing suspended
- Engine power derate on trucks and machines
- Likely causes
- Likely5 V supply or ground of the sensor interrupted or shorted
- PossibleDamaged harness or corroded connector at the dosing module
- PossibleAir pressure sensor failed internally
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.