P2037 code meaning
Reductant Injection Air Pressure Sensor A Circuit
Powertrain system Generic code P20xx codes Check engine light
What P2037 means
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.
P2037 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2037
- Engine or emission warning lamp on
- DEF dosing suspended
- Engine power derate on trucks and machines
Common causes of P2037
- Most 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
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant air pressure sensorReductant air pump
What each part of P2037 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| 37 | The exact fault in that area. |
What to do next
- Note P2037 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2037
What does P2037 mean?
P2037 means "Reductant Injection Air Pressure Sensor A Circuit". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P2037?
Drive gently and only to a workshop. With P2037 the car can go into limp mode (reduced power) to protect itself.
Will P2037 fail an emissions test?
Yes, it can. P2037 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2037 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. This is a job for a workshop.
Will P2037 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.