OBD-II Code
P0255
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$30–$2,500
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
$30 (connector clean) to $2,500 (full pump + PCM replacement on a VP44).
P0255 sets when the ECM detects an intermittent fault on the secondary fuel metering control circuit of the injection pump — most commonly an electronic rotary diesel pump like the Bosch VP44 or VP30, where a Pump Control Module (PCM/FPCM) on top of the pump modulates fuel quantity via a high-current solenoid. "Intermittent" is the key word: the fault drops in and out, often with heat soak, which means you cannot bench-test the pump cold and trust the result.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0255 sets when the ECM detects an intermittent fault on the secondary fuel metering control circuit of the injection pump — most commonly an electro…
P0255 sets when the ECM detects an intermittent fault on the secondary fuel metering control circuit of the injection pump — most commonly an electronic rotary diesel pump like the Bosch VP44 or VP30, where a Pump Control Module (PCM/FPCM) on top of the pump modulates fuel quantity via a high-current solenoid.
"Intermittent" is the key word
the fault drops in and out, often with heat soak, which means you cannot bench-test the pump cold and trust the result. Cheapest-first ladder: scan-tool live data for fuel delivery commanded vs actual and watch for momentary dropouts during a 20-minute drive cycle (commanded 30-50 mm3/stroke at cruise should track actual within +/- 2 mm3; any time actual collapses to 0 while commanded stays steady, the metering loop is failing). Wiggle-test the PCM connector and the harness on top of the pump with the engine idling — the connector pins corrode and the ribbon wires inside the pump module crack from underhood heat cycling. Then check pump-to-ECM communication wiring (continuity end-to-end, no chafing against the valve cover or intake horn) and verify clean 12V supply + ground at the PCM (drop test: less than 0.2V on the ground side under load). Expensive-misdiagnosis caveat: shops routinely sell a $1,200-$2,500 injection pump when the actual failure is the $400-$700 PCM module bolted to the top of that pump, or a $30 corroded connector — verify the module before condemning the pump body.
Vehicle-specific patterns1998-2002 Dodge RAM 2500/3500 with the Cummins 5.9L 24-valve and the Bosch VP44 injection pump is the textbook P0255 case — the PSG (Pump Solenoid Gr…
- 1998-2002Dodge RAM 2500/3500 with the Cummins 5.9L 24-valve and the Bosch VP44 injection pump is the textbook P0255 case — the PSG (Pump Solenoid Group / electronic control module) on top of the VP44 cooks from underhood heat sitting directly above the exhaust manifold, and starts dropping intermittent metering signals around 100k-150k miles; the famous fix is relocating the PCM off the pump with an extension harness kit.
- 1994-2003Ford 7.3L Powerstroke uses an Injector Driver Module (IDM) that can throw similar metering codes when the IDM connector corrodes or the IDM itself fails — the IDM lives on the driver fender and is easier to access than a VP44 module.
- 1994-2000GM 6.5L Detroit Diesel with the DS4 electronic injection pump has the well-documented PMD (Pump Mounted Driver) failure that throws metering and timing codes intermittently — the standard shop fix is relocating the PMD to a finned heatsink at the front bumper.
- 2003-2007Dodge RAM with the CP3 common-rail pump (5.9L and 6.7L Cummins) is a different architecture and rarely throws P0255 — if you see it on a CP3 truck, suspect wiring or ECM, not the pump itself.
Estimated repair$30 (connector clean) to $2,500 (full pump + PCM replacement on a VP44).
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