PACCAR MX P0315 is the fault-code chapter of the 2013 PACCAR MX Diagnostic Service Manual covering cylinder unbalance detected, the code that sits behind most contribution and misfire complaints. It is a one-trip MIL code with three drive cycle recovery, a misfire readiness group and a fuel freeze frame type. Detection is based on piston acceleration converted to crankshaft acceleration, measured from the crankshaft sensor F552 signal.
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, pages 239 to 243 |
| Pages | 5 |
| File size | 0.5 MB |
| Format | |
| Language | English |
What the PACCAR MX P0315 chapter covers
- Diagnostic window: the check runs 30 seconds after start, at steady speed and load between 600 and 1900 rpm
- Set condition: the PCI ECU D420 detects an imbalance for more than 500 crankshaft revolutions
- Crankshaft sensor pin functions at D420 A55 ground, A56 signal and A59 shield
- Resistance of 774 to 964 Ω at 20°C and AC readings while cranking, at idle and at 1200 rpm
- Possible causes limited to fuel injector failure and mechanical engine failure
- The role of the crankshaft signal in synchronisation, misfire checks and camshaft backup
Diagnostic step sequence and verification
Inside PACCAR MX P0315 the procedure runs as follows. Four steps follow the visual inspection. The crankshaft sensor comes out for a contamination and damage check, with cleaning or replacement branching straight to verification. The flywheel is inspected next, and damage is referred to Rapido for repair. Step four reprograms the PCI with the most current PRS file and calls for a test drive, and a code that survives that goes to the Engine Support Center.
Trucks and engines it applies to
The chapter covers EPA 2013 PACCAR MX engines in Kenworth and Peterbilt trucks, and assumes PCI supply power and ground are already proven good before the tree is entered. Model programmes and dealer support for these engines are listed on the PACCAR corporate site.
Who needs the PACCAR MX P0315 chapter
This is the chapter to open before any contribution or misfire code is chased, because it defines the road test that validates a repair: coolant above 70°C, then accelerations and load transitions.
The complete PDF of the PACCAR MX P0315 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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