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Trouble code
P2200: NOx sensor circuit
The same code points to different failures on different engines. Below, engine by engine, are the documented failures whose records name P2200, with the record's own words, how to tell them apart and the usual fix. The meaning above is taken from the record DEF / SCR / NOx sensor faults.
6.7 Power Stroke (2011-present)6.7 Cummins 2007-2018Duramax L5P (2017-present)
6.7 Power Stroke (2011-present)
1 documented failure names this code. All about this engine
verified
How widespread: Very common
112 NHTSA owner complaints match it, out of 1,754 checked
Where its record names the code
- check-engine light with codes P20EE (SCR efficiency below threshold), P2200-series (NOx sensor circuit/performance), P204F (reductant/DEF system performance)
Its other signs
- progressive derate warnings culminating in a 5mph limp if unaddressed
- DEF warnings/low-dose faults that persist even with a freshly filled, good-quality tank
How to tell it apart
- verify actual dosing BEFORE replacing any sensor: test DEF concentration with a refractometer, inspect the DEF injector tip for crystal buildup, confirm commanded dosing with a scan tool, check for exhaust leaks upstream of the sensors
- NOx sensors are not cheap - do not condemn one without first ruling out the injector/DEF-quality/leak alternatives above
Usual fix
replace a confirmed-failed NOx sensor (upstream or downstream of the SCR catalyst) only after verifying dosing
Root cause, parts and sources →
6.7 Cummins 2007-2018
1 documented failure names this code. All about this engine
verified
How widespread: Common
43 NHTSA owner complaints match it, out of 1,355 checked
Where its record names the code
- NOx sensor DTCs (P2200-family); 'DEF quality poor' messages
Its other signs
- DEF-system warning / 'service DEF system' message, then 5 mph derate if ignored
- DEF pump / heater failure, especially after a freeze (pump assembly contains a heater)
- white crystalline urea deposits around the DEF tank, pump and injector
- failed emissions test / MIL with no driveability change
How to tell it apart
- read DEF/SCR DTCs and current DEF quality / NOx PIDs before parts-cannoning
- inspect DEF for contamination/crystals; sample age - DEF has a shelf life and degrades with heat
- verify tank heater and pump operation on a cold morning (freeze-related no-starts of the dosing system)
Usual fix
drain and flush contaminated DEF; fresh DEF (dated stock, stored cool); clear crystals from the injector
Root cause, parts and sources →
Duramax L5P (2017-present)
1 documented failure names this code. All about this engine
verified
How widespread: Common
Where its record names the code
Its other signs
- check-engine light with SCR/NOx efficiency codes ('service emissions system')
- downstream NOx reading drifting toward the upstream value (a healthy SCR shows roughly a 70-90% reduction)
How to tell it apart
- compare live upstream vs downstream NOx readings with a scan tool before replacing the sensor
- rule out DEF quality and dosing faults first - the codes are shared
Usual fix
replace the failed NOx sensor (upstream or downstream) after live-data diagnosis
Root cause, parts and sources →
A code tells you which system flagged a fault, not which part failed. Read it with the signs your truck shows: symptoms by engine. For your exact truck: check your VIN.