PACCAR MX P0107 is the fault code page for “Boost pressure – Voltage too low or short circuit to ground on ECU (D420) pin (A51)” in the 2013 PACCAR MX Diagnostic Service Manual. PACCAR publishes it for engines in the EPA 2013 emissions family, and it is worked with the DAVIE diagnostic software.
What this fault code means
The boost pressure sensor F802 measures pressure in the inlet manifold near cylinder 1. The manual explains that this reading sets the smoke limit, feeds the calculated soot and NOx emissions, and supplies the exhaust gas mass flow used for DEF dosing by the EAS-3 system, so a dead signal disturbs far more than boost display.
Set and reset conditions
The code sets when the PCI ECU detects that the sensor output voltage is too low. It changes to inactive immediately after the diagnostic runs and passes.
PACCAR MX P0107 wiring and technical data
The manual pairs ECU D420 with boost pressure sensor F802 and lists the three circuits you can measure at the harness connector. With the sensor unplugged and the ignition keyed on, the supply should read 5 V between sensor pins 2 and 4. The fault code information block records it as 1 trip MIL, 3 drive cycle recovery, readiness group none, freeze frame type Comprehensive.
| D420 pin | F802 pin | Function |
|---|---|---|
| A39 | 4 | Ground |
| A47 | 2 | Power supply |
| A51 | 1 | Signal, boost pressure |
Possible causes and working notes
- Faulty wiring
- Faulty connection
- Faulty sensor
The manual warns that this sensor cannot be checked with a multimeter or oscilloscope: monitor it with DAVIE, do the wiring check, then run the Quick Check.
Document details and format
| Field | Value |
|---|---|
| Brand | PACCAR |
| System group | DTCs, MX Engines (EPA2013) |
| Source publication | 2013 PACCAR MX Diagnostic Service Manual |
| Manual page | 107 |
| Pages | 8 |
| File size | 0.7 MB |
| Format | PDF, English |
Applies to PACCAR MX P0107 repairs
The page sits in the DTCs section for MX engines built to the EPA 2013 emissions standard, so it covers trucks running that engine family with the PCI engine control unit. Coverage and dealer support are published on the PACCAR corporate site.
Who needs this PACCAR MX P0107 page
Fleet technicians and independent diesel shops working a low boost, derate or emissions complaint on a PACCAR MX engine who need the factory pinout and step order.
The full PDF page is in the DiagTechPro manuals library; a free account downloads it. Keep the PACCAR MX P0107 sheet open next to DAVIE.
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