PACCAR MX P0278 is the fault-code chapter of the 2013 PACCAR MX Diagnostic Service Manual covering a decrease in combustion in cylinder 6 relative to the other cylinders, without causing complete failure. It closes the cylinder contribution series that runs from cylinder 1 through cylinder 6. Like the rest of that series it is one page long, and every field on it points to the Engine Support Center.
Document details at a glance
| Brand | PACCAR |
|---|---|
| Model coverage | PACCAR MX engines, EPA 2013 emissions level |
| System group | DTCs, MX Engines EPA2013 |
| Source publication | 2013 PACCAR MX Diagnostic Service Manual, page 231 |
| Pages | 1 |
| File size | 0.3 MB |
| Format | |
| Language | English |
What the PACCAR MX P0278 chapter covers
- The fault code description exactly as PACCAR words it for cylinder 6
- Its role as the last entry in the cylinder contribution sequence
- Confirmation that no diagnostic condition or set condition is given
- Confirmation that no wiring diagram or technical data is printed
- Confirmation that no cause list or numbered troubleshooting exists
- The published action: contact the Engine Support Center
Diagnostic step sequence and verification
Inside PACCAR MX P0278 the procedure runs as follows. With nothing printed on the page itself, the manual leaves the physical work to adjacent chapters. Cylinder 6 is served electrically by connector B461 and solenoid valve B426 in the injector chapters, which give resistance figures and a diode-check routine. The cylinder unbalance chapter names fuel injector failure and mechanical engine failure as the two candidate causes for an imbalance of this kind.
Trucks and engines it applies to
The entry covers EPA 2013 PACCAR MX six-cylinder engines in Kenworth and Peterbilt chassis, read through DAVIE alongside the rest of the code set. Model programmes and dealer support for these engines are listed on the PACCAR corporate site.
Who needs the PACCAR MX P0278 chapter
Anyone comparing a rear-cylinder complaint against the front cylinders needs this page to confirm the code exists and that its resolution runs through PACCAR support rather than a printed tree.
The complete PDF of the PACCAR MX P0278 chapter is filed in the DiagTechPro manuals library, where a free account is required to download it alongside the rest of the MX Engines EPA2013 fault-code set.
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