OBD-II trouble code
P0260: Injection Pump Fuel Metering Control "B" Intermittent (Cam/Rotor/Injector)
The second metering control fault is real, but it will not sit still long enough to be measured. Testing components that are working perfectly while you look at them is wasted effort — and on a two-channel engine you have a capture method the single-channel version of this code cannot offer.
Quick facts
- System
- Powertrain
- Category
- Fuel & Air
- Severity
- High severity
- Drivable
- No — stop driving until repaired
- Repair cost range
- $0 – $1,600
- DIY difficulty
- Advanced DIY
What does P0260 mean?
P0260 closes the injection pump fuel metering control block. P0256 through P0259 describe faults on the "B" channel that the module can see when it looks. P0260 describes one that appears, sets a code, and then vanishes — the module caught the second metering control misbehaving, stored it, and by the time the vehicle reached a scan tool everything read normally again. The fault is not imaginary. It is simply not available on demand.
As with the rest of this family, deal with the name first: the code says "Injector" and it is not an injector code. "(Cam/Rotor/Injector)" describes the cam ring and rotor inside a rotary distributor injection pump. Everything happens at or inside the pump, upstream of any injector.
That one characteristic — the fault is absent right now — changes the entire approach, and it is worth stating plainly because it runs against instinct: on an intermittent code, testing components is mostly wasted effort. A meter placed on a circuit that is behaving correctly at that moment tells you only that it is behaving correctly at that moment. The productive work is different in kind. It is about capturing the fault: recreating the conditions under which it occurs, and having data recording when it does.
Start with the freeze frame, which on this code is worth more than on almost any other. It is a snapshot of the exact operating conditions at the moment the fault set — engine speed, load, coolant temperature, vehicle speed, fuel pressure — and it is free. Read it and look for a pattern. A fault that only sets at high coolant temperature points at heat: expanding metal opening a marginal connection, or insulation that has hardened and cracks apart as it warms. A fault that sets only at low temperature points at fuel gelling, or at a connection that shrinks when cold. A fault that sets under load and never at idle points at supply volume or at harness movement caused by engine torque roll. A fault that sets on rough roads points at vibration and terminal tension. Each pattern leads somewhere different.
Now the thing that makes P0260 more tractable than P0255, its "A"-channel equivalent, and the single most useful idea on this page. An engine with a "B" metering control has an "A" metering control too, which means you can log both channels at once. Set up a recording of commanded and actual fuel quantity for "A" and "B" side by side, along with supply pressure, and drive the route that historically triggers the fault. When the event fires, the shape of the capture answers the question immediately. If "B" drops out while "A" tracks perfectly, the fault is confined to the "B" channel — its harness, its connector, its ground, its actuator — and the shared tank, filter, transfer pump, and common feed are all exonerated in a single event, without removing a part. If both channels wobble together at the same instant, the "B" channel is innocent and you are looking at something shared: supply volume, a common feed or relay, a shared ground, or fuel quality. On a single-channel engine you would have to prove that by elimination over days. Here one captured event does it.
The physical inspection that follows should target connections rather than components. The "B" actuator connector is usually the buried one — mounted on a second pump or a less accessible control element, low on the engine, hot, and vibrating continuously — and its harness runs longer and by a more convoluted route than the "A" harness to get there. That combination is exactly what produces intermittents. Check terminal tension against a matching pin rather than by eye, because a terminal that has lost its grip still looks perfectly normal sitting in the housing. Compare the "B" connector directly against the "A" connector: side by side, corrosion, a displaced seal, or evidence of past water intrusion is obvious in a way it is not when examining one alone. Then follow the harness looking for the two damage patterns that produce intermittents: shiny, flattened rub spots where it has moved against a bracket or the pump body, and stiff, dark, brittle sections where heat has hardened the insulation until flexing opens a crack.
When you do test, test under the conditions that produce the fault. A wiggle test on a cold engine in a workshop reproduces very little. The same test at full operating temperature, with a meter or scan tool recording, while you move each section of the "B" harness in turn, is one of the highest-yield things you can do on this code.
One piece of advice deserves emphasis because it is where money most often gets wasted: do not replace parts on this code speculatively. An intermittent that occurs once a week has an unhelpful property — after fitting a new actuator, a week of normal running feels like proof, and it is not. Unless you found something, the fault has simply not come back yet. Hold out for evidence: a captured event, a visible defect, or a measurement taken while the fault was actually present. That discipline matters more here than on the "A" channel, because reaching the "B" component usually costs more labor, so a speculative replacement is a more expensive mistake.
Driveability deserves the same seriousness as the rest of the family, arguably more. A vehicle that runs perfectly and then abruptly loses fuelling is more hazardous than one that runs badly all the time, because nothing warns you. If the intermittent has ever produced a stall while moving — which on a diesel takes power steering and vacuum brake assist with it — treat the vehicle as unsafe to drive until the fault is found.
Common causes
- Loose or low-tension terminal in the "B" metering actuator connector
- Corrosion in the "B" pump connector that conducts intermittently as it heats and cools
- Heat-hardened, cracked insulation on the longer "B" harness run that opens as the engine warms
- Chafed wire making and breaking contact against the pump body or a bracket with engine movement
- Vibration-fatigued wire strands broken inside intact insulation — an open only under movement
- Water intrusion into the connector, conducting or corroding depending on conditions
- Fuel gelling in cold weather producing supply restriction that comes and goes with temperature
- Marginal lift/transfer pump output that falls below specification only under peak demand
- Intermittently sticking "B" metering actuator from deposits or wear
- "B" actuator coil breaking down only when hot — a resistance that reads normal cold and fails at temperature
- Poor ground that conducts adequately most of the time and fails under load or vibration
- Shared feed, relay, or ground fault that affects both channels, which a two-channel data log will reveal immediately
Symptoms
- Check engine light that comes on and later goes off by itself, with P0260 stored or pending
- Occasional stalling with no warning, then normal running afterwards
- Intermittent hard starting with no consistent pattern
- Momentary power loss or a brief limp mode that clears on the next restart
- Surging, hesitation, or a brief bank-to-bank imbalance that appears for a few seconds and resolves
- Fault correlating with rough roads, hard cornering, or engine temperature
- Occasional puff of black smoke during an episode
- Everything reads normal on a scan tool by the time the vehicle is inspected
- Fuel economy slightly worse than expected across a tank despite normal-feeling driving
- Commanded and actual fuel quantity on the "B" channel briefly diverging in a data log while "A" tracks normally
Diagnostic steps
- 1.Accept what the code is telling you: the fault is not present right now. Testing components that are currently working will not find it, so plan around capturing the event instead.
- 2.Read and record the freeze frame in full. Engine speed, load, coolant temperature, vehicle speed, and fuel pressure at the moment of the fault are the most valuable data you have.
- 3.Look for a pattern in the freeze frame. Hot-only suggests thermal expansion or heat-cracked insulation; cold-only suggests fuel gelling; load-only suggests supply volume or harness movement; rough-road correlation suggests terminal tension.
- 4.Record all other stored, pending, and history codes. A companion code often localises what the intermittent is affecting.
- 5.Identify from service data which physical component your manufacturer calls the "B" metering control and where it is mounted, before planning any access work.
- 6.Set up a data log of commanded and actual fuel quantity for BOTH channels plus supply pressure, then drive the route that historically triggers the fault.
- 7.Read the capture: "B" dropping out while "A" tracks confines the fault to the "B" channel; both channels wobbling together points at a shared feed, ground, or fuel supply problem instead.
- 8.Inspect the "B" connector properly — check terminal tension against a matching pin rather than by eye, and look for corrosion, a displaced seal, and evidence of past water intrusion.
- 9.Compare the "B" connector directly against the "A" connector. Side by side, a marginal connector is obvious in a way it is not on its own.
- 10.Follow the "B" harness looking for the two intermittent signatures: shiny flattened rub spots, and stiff dark brittle insulation that cracks when flexed.
- 11.Flex each harness section by hand at full operating temperature while watching a live data parameter or a meter, since a cold workshop test reproduces very little.
- 12.Measure fuel supply pressure under peak demand rather than at idle, since a marginal lift pump only falls short when asked for volume.
- 13.Check fuel quality and drain the water separator, especially if the pattern is cold-weather-only.
- 14.Test the "B" actuator ground for low resistance under load, and repeat the test while the harness is being moved.
- 15.Check manufacturer service bulletins, since intermittent pump harness and connector faults are exactly the kind of issue that generates them.
- 16.Do not replace parts speculatively. Wait for a captured event, a visible defect, or a measurement taken while the fault was actually present.
Repair cost
$0 – $1,600
The low end of this range is genuinely zero, because a meaningful share of intermittents on this circuit turn out to be a connector that needs nothing more than unplugging, cleaning, and reseating. Diagnosis is the real expense and it is higher than usual, typically $180-$400 — above the "A"-channel equivalent, because the "B" component is usually the harder one to reach and identifying it correctly takes time on an unfamiliar engine. A connector or terminal repair lands at $120-$400. Harness repair for a chafed or heat-damaged section generally runs $250-$750, reflecting the longer and more awkward "B" harness run. A fuel filter, if the pattern points at cold-weather gelling, is $60-$220. A lift/transfer pump replacement runs $250-$900. A "B" fuel control actuator is $250-$1,100 installed on most engines. The important caveat on this code is that money spent on diagnosis is better spent than money spent on parts, because an intermittent that has not returned for a week is not evidence that a new part fixed it.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with diesel injection pump / fuel control actuator service preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an advanced DIY job. It typically requires specialty tools, scan-tool access, lifting equipment, or careful sequencing to avoid causing new failures. Plan for extended downtime and have a backup vehicle. Most owners are better served by a shop that has done this repair before.