Description
Outlet (downstream) NOx sensor for Mack and Volvo MP/D-platform heavy-duty diesel engines — PAI 853760. Mounts downstream of the SCR catalyst and reports tailpipe NOx to the aftertreatment ECU, closing the loop on DEF dosing efficiency. The 4-pin rectangular connector, M20 × 1.5 exhaust boss, and 28″ overall harness length match Mack/Volvo OEM 22014032 and 22303391.
Signs You Need a New NOx Sensor
- Aftertreatment fault codes referencing the downstream / outlet NOx sensor (SPN 4364 / 4334 / 3226 etc.)
- SCR efficiency derate or torque limit triggered by NOx-related DTCs
- DEF consumption no longer correlates with engine load
- MIL or check-engine warning with NOx outlet sensor heater faults
Specifications
| Manufacturer | PAI Industries |
|---|---|
| Part Number | 853760 |
| Part Type | Outlet NOx Sensor (downstream of SCR) |
| Connector | 4-pin rectangular |
| Thread | M20 × 1.5 exhaust boss |
| Plug Width | 1.09 in |
| Harness Length | 28.00 in (711 mm) overall |
| Finish | Black / silver |
Cross References
This sensor replaces or is equivalent to the following part numbers:
- Mack: 21346963, 21479637, 21567763, 21636088, 22014032, 64MT493M
- Mack / Volvo: 22303391
- Volvo: 21346963, 21479637, 22014032, 22303391
- Also known as: 5WK97366
Applications
This outlet NOx sensor fits the SCR aftertreatment system on Mack and Volvo trucks running:
- Mack MP7 / MP8 (EPA10 and later)
- Volvo D11 / D13 / D16 (EPA10 and later)
Representative chassis: Mack Pinnacle CXU/CHU, Granite GU, Anthem; Volvo VNL, VNM, VNR, VNX, VHD.
Verify the sensor is in the outlet (downstream) position — the inlet NOx sensor (Mack 21636091, see PAI 853761) looks similar but uses a different OEM number and 23″ harness. After installation, an aftertreatment relearn / DEF system reset may be required.









