This is the 2013 PACCAR MX Diagnostic Service Manual covering fault code P1298, which relates to PACCAR MX engine oil sensor diagnostics and repair verification. Published by PACCAR for their MX engine platform, this technical guide provides mechanics and workshop owners with complete troubleshooting procedures for oil temperature faults flagged as moderately severe by the engine control unit.
The document focuses on the oil temperature sensor (F808) located in the oil module before the oil cooler, detailing how the PCI ECU monitors oil temperature continuously and sets the P1298 code when measured temperature exceeds 125°C (257°F) for more than 60 seconds.
Document details and specifications — PACCAR MX engine
| Brand | PACCAR |
| Model coverage | PACCAR MX Engines |
| System/Group | DTCs / MX Engines (EPA2013) |
| Publication number | P1298 |
| Year/Revision | 2013 |
| Pages | 8 |
| File size | 0.7 MB |
| Format | |
| Language | English |
Table of contents
- Fault code P1298 description and information
- Component description — Oil temperature sensor (F808)
- Diagnostic condition and set/reset conditions
- Electrical diagrams and wiring pinout (D420 PCI ECU, F808 connector)
- Technical data — Component resistance checks at various temperatures
- Possible causes and additional information
- Step-by-Step Diagnostics: Investigate related trouble codes (P0197, P0198)
- Step 2: Oil temperature sensor checks (visual inspection, DAVIE monitoring, electrical resistance and supply voltage)
- Step 3: Repair verification cycles and Quick Check procedure
- PACCAR Engine Support Center contact information
Applies to these models
This manual applies exclusively to PACCAR MX engines from the 2013 EPA emissions generation. The PACCAR MX engine oil diagnostic procedures cover all trucks equipped with the PCI ECU (D420) and F808 oil temperature sensor assembly. PACCAR official website.
Who needs this PACCAR MX engine oil manual
Diesel mechanics, engine diagnosticians, and heavy-truck workshop owners requiring a factory-level diagnostic reference for MX engine oil faults will find this manual essential. The step-by-step troubleshooting, electrical schematics, and sensor resistance tables enable rapid fault isolation and component verification without guesswork.
The complete 8-page PDF is available in the DiagTechPro manuals library. A free account is required to download.
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