PACCAR MX P104D is the diagnostic trouble code documented on this 6 pages extract from the 2013 PACCAR MX Diagnostic Service Manual, published by PACCAR for EPA2013 MX engines. PACCAR prints the fault as “Pressure before turbine – Data valid but too high”, in the manual’s standard fault code layout.
Document details for PACCAR MX P104D
| Brand | PACCAR |
|---|---|
| Model coverage | PACCAR MX engines, EPA2013 emissions level |
| System / group | DTCs / MX Engines (EPA2013) |
| Source publication | 2013 PACCAR MX Diagnostic Service Manual |
| Fault code | P104D — Pressure before turbine – Data valid but too high |
| Pages | 6 |
| File size | 0.6 MB |
| Format | |
| Language | English |
Fault code summary and monitor data
The manual lists 2 trip MIL with 3 drive cycle recovery, no readiness group and a generic freeze frame type. The diagnostic runs between 1000 and 1700 rpm at steady load with coolant above 50 C.
- Code number
- Fault code description
- Fault code information
- Description of component(s)
- Set condition of fault code
- Reset condition of fault code
- Possible causes
- Diagnostic Step-by-Step
- Verification Drive Cycle
Component and system background
Exhaust gas pressure before the turbine is measured through a steel tube ahead of the EGR valve. The signal controls the VTG turbocharger, the EGR flow, the BPV valve and the engine brake, and it is used to calculate exhaust gas temperature before the turbine, where a lower measured pressure produces a higher calculated temperature.
Set and reset conditions for PACCAR MX P104D
The code is set when the PCI ECU (D420) detects that the measured pressure before turbine is higher than expected for more than 50 seconds. Listed causes are a blocked exhaust system, a restricted pressure sensor tube and pressure sensor deviation. Validation asks for coolant of at least 70 C, then a minimum of 80 km/h (50 mph) in the highest gear possible, best performed on a level grade road under load.
Applies to EPA2013 MX engines
The PACCAR MX P104D entry sits in the DTCs / MX Engines (EPA2013) section, so it applies to PACCAR MX engines built to that emissions level. Manufacturer product information is published on the PACCAR corporate website.
Who needs the PACCAR MX P104D fault code page
Technicians reading a live code, foremen writing an estimate and fleet managers deciding whether a truck stays in service all need the manufacturer wording rather than a generic code list.
The full PDF for MX P104D is in the DiagTechPro manuals library; a free account is required to download it.
Related manuals library
