Heavy-Duty Diesel Sensor Location Hub
Professional diagrams, exact locations, access instructions, and connector positions for the most common heavy-duty diesel engines in North America — Cummins X15, PACCAR MX-13, Detroit DD15, and Volvo/Mack MP8.
Driver/passenger side, front/rear, bracket positions
What to remove, clearance needed, torque specs
SPN/FMI codes triggered by each sensor
Run a structured test sequence in the diagnostic engine
Cummins X15 Sensor Locations
The Cummins X15 is the most widely deployed heavy-duty diesel engine in North America. Sensor access varies by model year (2017+ Efficiency Series vs. Performance Series).
Sensor List — Cummins X15
MAP Sensor (Boost Pressure)
Intake manifold, driver side top
IAT Sensor
Intake manifold, near MAP sensor
Turbo Speed Sensor
Turbocharger compressor housing
VGT Position Sensor
Turbocharger actuator, passenger side
Crankshaft Position Sensor
Front gear housing, lower driver side
Camshaft Position Sensor
Front gear housing, upper
Fuel Rail Pressure Sensor
High-pressure common rail, driver side
DPF Differential Pressure Sensor
Aftertreatment housing bracket
NOx Sensor — Inlet
Exhaust pipe before DOC
NOx Sensor — Outlet
Exhaust pipe after SCR
DOC Inlet Temp Sensor
Exhaust pipe, DOC inlet flange
SCR Outlet Temp Sensor
Exhaust pipe, SCR outlet
Common Related Fault Codes
Run a guided diagnosis for any Cummins X15 fault code
Start DiagnosisPACCAR MX-13 Sensor Locations
The PACCAR MX-13 powers Kenworth and Peterbilt trucks. The EGR system and aftertreatment sensor locations differ significantly from Cummins platforms.
Sensor List — PACCAR MX-13
EGR Differential Pressure Sensor
EGR cooler outlet, driver side
Boost Pressure Sensor
Intake manifold, top center
Fuel Rail Pressure Sensor
High-pressure rail, passenger side
NOx Sensor — Inlet
Exhaust manifold outlet, before DOC
NOx Sensor — Outlet
After SCR catalyst
DPF Pressure Sensor
Aftertreatment bracket, passenger side
DOC Inlet Temp Sensor
Exhaust pipe, DOC inlet
DPF Outlet Temp Sensor
Between DPF and SCR
SCR Outlet Temp Sensor
After SCR, before tailpipe
Turbo Actuator Position Sensor
VGT actuator on turbocharger
Common Related Fault Codes
Run a guided diagnosis for any PACCAR MX-13 fault code
Start DiagnosisDetroit DD15 Sensor Locations
The Detroit DD15 is the flagship engine for Freightliner and Western Star trucks. The DEF dosing system and integrated aftertreatment module have unique sensor access points.
Sensor List — Detroit DD15
DEF Dosing Unit Sensors
DEF dosing module, passenger side frame rail
DOC Inlet Temp Sensor
Exhaust pipe, DOC inlet flange
DPF Pressure Sensor
Aftertreatment module bracket
SCR Outlet Temp Sensor
SCR outlet, after catalyst
Fuel System Pressure Sensor
High-pressure fuel rail, driver side
Turbo/VGT Position Sensor
VGT actuator on turbocharger housing
Crankshaft Position Sensor
Flywheel housing, lower rear
Camshaft Position Sensor
Front gear cover, upper
NOx Sensor — Inlet
Exhaust pipe before DOC
NOx Sensor — Outlet
After SCR catalyst
Common Related Fault Codes
Run a guided diagnosis for any Detroit DD15 fault code
Start DiagnosisVolvo/Mack MP8 Sensor Locations
The Volvo/Mack MP8 powers Volvo VNL and Mack Anthem trucks. The aftertreatment system is integrated into a single module with unique sensor access from underneath.
Sensor List — Volvo/Mack MP8
Aftertreatment Inlet Temp Sensor
Exhaust pipe, before DOC
DPF Outlet Temp Sensor
Between DPF and SCR
SCR Outlet Temp Sensor
After SCR catalyst
DPF Pressure Sensor
Aftertreatment module, top bracket
NOx Sensor — Inlet
Exhaust pipe, before DOC inlet
NOx Sensor — Outlet
After SCR, near tailpipe
Fuel Pressure Sensor
High-pressure fuel rail, driver side
Boost Pressure Sensor
Intake manifold, top
Turbo Speed Sensor
Turbocharger compressor housing
Common Related Fault Codes
Run a guided diagnosis for any Volvo/Mack MP8 fault code
Start DiagnosisWhy Sensor-Location Searches Are High-Intent
When a technician searches "X15 fuel rail pressure sensor location" or "DD15 NOx sensor location," they are actively diagnosing a truck — not researching. These are among the highest-intent queries in diesel repair. AI Diesel Tech provides exact locations, connector positions, and related fault codes so technicians can get to the sensor and test it without guessing.
Exact physical location
Driver/passenger side, front/rear, bracket or housing position
Connector & harness info
Pin count, connector type, harness routing from ECM
Related SPN/FMI codes
Every fault code that sensor can trigger, with test procedures
Frequently Asked Questions
Where is the fuel rail pressure sensor on a Cummins X15?
On the Cummins X15, the fuel rail pressure sensor is located on the high-pressure common rail, typically on the driver side of the engine near the fuel rail manifold. It uses a 3-pin Deutsch connector and monitors rail pressure for SPN 157/164 fault codes.
Where is the NOx sensor on a Detroit DD15?
The DD15 has two NOx sensors: the upstream (inlet) NOx sensor is located before the DOC in the exhaust pipe, and the downstream (outlet) NOx sensor is located after the SCR catalyst. Both use 6-pin connectors and are accessible from under the truck.
Where is the DPF pressure sensor on a PACCAR MX-13?
The PACCAR MX-13 DPF differential pressure sensor is mounted on the aftertreatment housing bracket, with two hose connections running to the DPF inlet and outlet ports. It is typically accessible from the passenger side of the vehicle.
Where is the boost pressure sensor on a Volvo MP8?
On the Volvo/Mack MP8, the boost pressure sensor (MAP sensor) is located on the intake manifold, typically on the top or side of the manifold near the turbocharger outlet. It monitors SPN 102 and uses a 3-pin connector.
What sensors are color-coded in the diagrams?
In the AI Diesel Tech sensor diagrams: aftertreatment sensors (NOx, DPF pressure, EGT) are highlighted in yellow/orange; fuel system sensors (fuel rail pressure) in blue; air system sensors (MAP, IAT, turbo speed) in green; turbo/VGT actuators in red; crankshaft and camshaft sensors in white.
AI Diesel Tech — The Technician's Diagnostic Engine
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