This is the 2013 PACCAR MX intercooler temperature diagnostic service manual covering DTC P1127, published by PACCAR for EPA 2013 compliant MX engines. The document provides comprehensive fault code identification, electrical schematics, component testing procedures, and step-by-step repair verification cycles for mechanics and workshop technicians diagnosing intercooler outlet temperature sensor failures.
DTC P1127 is triggered when the PCI ECU detects that intercooler outlet temperature exceeds 95°C (203°F) for more than 60 seconds, indicating moderately severe performance degradation in the charge air cooling system.
Document details and specifications — PACCAR MX intercooler
| Brand | PACCAR |
| Model coverage | MX Engines (EPA 2013) |
| System/Group | DTCs / MX Engines |
| Year/Revision | 2013 |
| Pages | 8 |
| File size | 0.6 MB |
| Format | |
| Language | English |
Table of contents
- Fault code P1127 description and information
- Component description: intercooler outlet temperature sensor location
- Set and reset conditions for P1127
- Electrical diagrams and connector pin assignments (D420 PCI ECU, F750 sensor)
- Technical data and component resistance values at multiple temperatures
- Possible causes: contaminated intercooler, faulty cooling fan, sensor deviation, winterfront restrictions
- Step-by-Step diagnostic procedure (6 investigation steps)
- Related trouble codes reference (P0072, P0073, P009A, P0115, P0117, P0118, and others)
- Visual inspection checklist for intercooler and air system components
- Electrical checks: resistance and supply voltage testing
- DAVIE monitor procedures for temperature and pressure comparison
- Intake/exhaust leak test procedures using kit #1903034
- Repair verification cycles and Quick Check validation
- PACCAR Engine Support Center contact information
Applies to these models
This manual applies to trucks equipped with PACCAR MX engines compliant with EPA 2013 emissions standards. The diagnostic procedures cover the intercooler temperature sensor (component F750) and its integration with the PCI ECU (D420) controlling turbo boost and EGR systems. For more information about PACCAR engines and support, visit PACCAR official website.
Who needs this PACCAR MX intercooler temperature manual
Diesel mechanics, heavy truck technicians, and workshop managers responsible for diagnosing and repairing PACCAR MX engine performance codes require this PACCAR MX intercooler temperature reference. The manual guides fault isolation from sensor electrical failures through intake system contamination and cooling fan operation, ensuring accurate root cause identification before component replacement.
The complete MX intercooler temperature diagnostic PDF is available in the DiagTechPro manuals library. A free account is required to download this 8-page service document.
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