Exhaust Temperature Sensors: Position, Type and Part Identity
Back to the ATP Garage guide libraryDPF, DEF & SCR / Exhaust-temperature sensor identity
Quick answer: Identify an exhaust-temperature sensor by its actual physical position, specified operating type and complete service-assembly identity, together with the truck, engine and emissions application. A scanner's sensor number, a similar connector or a familiar probe shape does not establish the replacement.
Application: General identification guidance. NTK's UK car/light-commercial technical introduction supplies technology/position concepts, not heavy-truck fitment. Detroit EPA07 component names and Volvo Buses RD18-002 are separate historical application examples.
What does an exhaust-temperature sensor measure?
An EGT sensor measures exhaust-gas temperature. NTK describes its use in component-temperature protection and aftertreatment heat-cycle monitoring, with sensors fitted at multiple exhaust-system positions. The part request must identify which position and assembly the diagnosis concerns. [1]
Keep the parameter name in the report. An EGT request is different from the particulate/pressure-sensor question or a NOx-sensor request. Ask the service provider to reconcile the displayed parameter, physical component and quoted part rather than letting the word "exhaust sensor" stand in for all three.
Why is "sensor 2" insufficient for a replacement order?
NTK's technical introduction warns that position numbering can differ between vehicle brands. Its catalog terminology also uses locations relative to a component, such as pre/post turbo or DPF. Preserve the exact manufacturer position name and map it to the actual installation rather than transferring another vehicle's numbering. [1]
For a scoped example, Detroit's EPA07 component descriptions separately name DOC inlet, DOC outlet and DPF outlet temperature sensors. Those location names explain which exhaust condition is being measured. They are not a universal sensor-count or layout chart for later Detroit or other-make systems. [2]
| Field | Evidence to retain | Question it resolves |
|---|---|---|
| Vehicle and system | VIN, installed engine/control identity, emissions and aftertreatment labels | Which application is installed? |
| Position | Complete diagnostic name, physical location and surrounding landmarks | Which exact measurement point is requested? |
| Operating type | Current application information and complete sensor marking | Which specified sensor technology belongs here? |
| Service assembly | Probe, cable/connector and accessible mounting views | What is supplied, and what must match? |
| Finding and history | Complete fault/status, assessment and recent work | Why is this item being requested? |
Take an overall accessible installation view before a close label view, and identify the relevant exhaust component in the record. Where the physical location and scanner label disagree, retain both and ask for clarification. Do not change a connection merely to see whether a warning moves.
Why must operating type be confirmed as well as the connector?
NTK distinguishes positive-temperature-coefficient (PTC) and negative-temperature-coefficient (NTC) sensing: their resistance changes in opposite directions as temperature rises. Its introduction says the replacement must match the applicable operating principle. This is a technology distinction, not a resistance test or interchange approval for a truck. [1]
Have the supplier confirm the exact service assembly through current application information. Preserve readable markings, connector identification, cable routing and mounting context. A matching plug does not settle the sensing type or position. Do not splice, shorten or combine unidentified sensor parts to create an apparent match.
Does a temperature-related code prove the probe has failed?
Keep the complete code/status and matched diagnostic finding. Volvo Buses RD18-002, dated August 18, 2018, lists P2084-64 under its stated US13-US20 emissions scope. Its possible causes include incorrect EGT location on the DPF, exhaust leakage, wiring, connector and sensor issues. The document also calls out control-module update status. [3]
This bus example explains why recent work, physical position and connection history belong with the complaint. It is not a repair instruction or part match for every Volvo/Mack truck. Ask the provider which current procedure applies and what finding confirms the item to be replaced; keep unresolved possibilities visible.
What should be confirmed before the sensor is ordered?
Combine the application and position record with the confirmed defect. Ask whether the quote supplies the complete required sensor/cable assembly, which associated items are included and which installation or setup requirements remain. Where the label is missing, disclose it and obtain the next required evidence instead of completing a number by guesswork.
The installer should use the current matched procedure, including its handling, routing and tightening requirements, and retain the required final verification. This guide supplies no universal temperature limit, resistance chart, removal sequence or tightening value. Obtain photos only through safe access after the relevant components have cooled.
For a wider system complaint, use the SCR-efficiency evidence guide and the appropriate engine-specific guide in the Garage library. Keep the confirmed sensor identity attached to any later quote or repair revision.
Common exhaust-temperature sensor questions
Can I order using only the scanner's sensor number?
Map the complete manufacturer label to the actual physical position and current application. Do not transfer numbering between vehicles.
Does an identical-looking connector establish fitment?
No. Confirm the position, operating type and complete service assembly against current application information.
Are PTC and NTC sensors the same operating type?
No. NTK describes opposite resistance/temperature relationships. Obtain the exact match; this article supplies no electrical test limit.
Does the legacy Detroit example identify every later sensor position?
No. Its EPA07 component names illustrate one documented layout, not every later engine or aftertreatment arrangement.
Does P2084-64 automatically identify a failed sensor?
Use the matched diagnostic. The separately scoped Volvo bus example includes other possible causes and installation position.
What if the location name and installed connection do not agree?
Preserve both records and ask the provider to resolve the discrepancy before selecting or fitting a replacement.
Manufacturer sources and application limits
Dated examples explain the decision and its limits. Use current service information for the actual engine, emissions configuration, software and installed aftertreatment. No universal test threshold or replacement authorization is supplied here.
- NTK/Niterra UK, EGT Sensor Technical Information, PDF page 4. Relevant position, PTC/NTC and numbering discussion in the UK car/light-commercial catalog; no heavy-truck fitment or conversion rows transferred. April2023 filename is not asserted as a printed issue date.
- Detroit, EPA07 Aftertreatment System Technician's Guide, DDC-SVC-MAN-0036, section 3.1 Aftertreatment Device. Component descriptions and relevant inspection distinctions; checked November 4, 2026. Legacy layout only; URL dates are not asserted issue dates. No service sequence or numeric limits transferred.
- Volvo Buses remote diagnostics RD18-002, dated August 18, 2018, P2084-64, stated US13-US20 emissions. Historical bus diagnostic example; no truck interchange, part-number list or replacement sequence copied. Manufacturer PDF at NHTSA.
Send the confirmed component request
Use the fitment verification form with the truck/engine and aftertreatment identities, complete markings, installed position, diagnostic finding and accessible photographs. Part fitment, package contents and availability require confirmation.
Related guide: Particulate Sensor or DPF Pressure Sensor? Know the Difference.
