This is the 2013 PACCAR MX Diagnostic Service Manual covering exhaust temperature sensor P3983 tampering code P3983. Published by PACCAR, this 4-page technical document provides mechanics and technicians with complete diagnostic procedures, wiring diagrams, and repair sequences for exhaust temperature sensor faults on EPA 2013–compliant MX engines.
Code P3983 indicates that the exhaust temperature sensor before the SCR catalyst has been tampered with or is operating outside expected parameters during normal engine operation. The manual addresses both pre-catalyst (F841) and post-catalyst (F842) temperature sensors, which are integral to the SCR catalyst temperature sensor ECU (D419) and cannot be serviced independently.
Document details and specifications — exhaust temperature sensor
| Brand | PACCAR |
| Model coverage | MX Engines (EPA 2013) |
| System/Group | DTCs / MX Engines (EPA2013) |
| Publication number | P3983 |
| Year/Revision | 2013 |
| Pages | 4 |
| File size | 0.4 MB |
| Format | |
| Language | English |
Table of contents
- Code P3983 description and fault information
- Description of exhaust temperature sensors before and after SCR catalyst
- Effect of sensor output signals on DEF injection and SCR catalyst protection
- Component location and diagnostic running conditions
- Fault code set and reset conditions
- Electrical diagram and wiring harness connector D419 pinout
- Technical data: component and wiring checks for ECU temperature sensors (D419)
- A-CAN circuit resistance measurements and specifications
- Possible causes: SCR catalyst temperature sensors ECU malfunction
- Additional information regarding cascading fault codes P1518, P151A, P151B
- Step-by-step diagnostic troubleshooting procedure
- Verification drive cycle for repair validation
Applies to these models
This exhaust temperature sensor P3983 diagnostic manual applies to all 2013 PACCAR MX engines equipped with EPA 2013 emissions control systems, including selective catalytic reduction (SCR) technology. The document covers diagnosis of the pre-SCR catalyst temperature sensor (F841), post-catalyst temperature sensor (F842), and their integrated ECU control module (D419). PACCAR official website
Who needs this exhaust temperature sensor P3983 manual
This temperature sensor P3983 troubleshooting guide is essential for diesel mechanics, service technicians, and workshop owners diagnosing emissions-related faults on PACCAR MX–powered trucks. Technicians using DAVIE diagnostic software will rely on this document to interpret code P3983, perform electrical component testing, and execute wiring harness inspections according to manufacturer specifications.
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