OBD-II trouble code
P2062: Reductant/Regeneration Supply Control Circuit/Open
The supply pump has a job nobody watches: after you switch off, it empties the lines so the fluid inside cannot freeze and split them. That means you can command a full test event with no scan tool at all — and it means an unrepaired open here does its real damage in the parking lot, not on the road.
Quick facts
- System
- Powertrain
- Category
- Exhaust / Aftertreatment
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $130 – $1,800
- DIY difficulty
- Advanced DIY
Browse every code in P2000–P20E8, or start from the full code library.
What does P2062 mean?
Every reductant system needs something to move fluid from the tank to the injector, and on most designs that something is an electric supply pump — sometimes called the transfer or delivery pump — living in or on the tank header assembly. P2062 is the module reporting that the circuit it uses to command that pump is open: it asked for supply and no current flowed.
The title carries a slash because the same address is used for two related jobs. On selective catalytic reduction vehicles it is the diesel exhaust fluid supply. On some platforms that perform active particulate filter regeneration by delivering fuel to a downstream injector, the same standard address covers the supply for that delivery instead. The component, its location, its cost and what breaks when it stops are all different between the two, so the first genuinely useful step is not a meter reading. It is establishing what this circuit supplies on the vehicle in front of you, because chasing a DEF pump on a system that dispenses fuel wastes an afternoon.
What makes this component unusual, and what most explanations skip, is that the supply pump does not only run while the engine is running. Urea solution freezes at around twelve degrees Fahrenheit and expands as it does, which would split lines and crack fittings if it were left standing in them. So the system clears itself: at key-off, most designs run the supply pump in reverse or open a return path and pull the fluid back down into the tank, where a heater and a large thermal mass protect it. That purge takes anywhere from a few seconds to several minutes, and the pump is audible for all of it.
That behaviour is worth knowing for two separate reasons. The first is diagnostic and free. If the purge cycle exists on this vehicle, shutting the engine off is a full commanded run of the pump — you can stand at the tank, listen, and learn whether the circuit does anything at all before a scan tool comes out of the bag. A pump that is silent at key-off on a system that should purge is consistent with this code; one that runs is telling you the circuit works and the fault is intermittent or elsewhere. The second reason is about consequence. An open supply control circuit means the purge stops happening, so fluid is left standing in lines and in the doser through every cold night until the code is fixed. In a warm climate that costs nothing. In a climate with hard freezes it can turn an electrical repair into a set of replaced lines and possibly a replaced injector, and that is a cost that accrues while the vehicle simply sits.
One more structural point makes this code easier to place than it looks. Supply is upstream of everything else in the reductant system. No supply means no pressure, which means no dosing, which means the pressure, flow and efficiency monitors all have something to complain about. P2062 therefore very often arrives inside a cluster of codes, and the cluster is not eight problems. Reading the freeze-frame data and the order in which the codes set usually shows this one first, with the rest as consequences — which is the difference between replacing a doser and repairing a connector.
Common causes
- Open in the supply pump control wire between the module and the tank header connector
- Corroded or disconnected connector at the tank header, often disturbed by earlier tank or filter work
- Supply pump motor winding open from wear or internal corrosion
- Blown fuse or open power feed for the reductant supply circuit
- Relay coil open or relay socket terminals no longer making contact
- Module driver output for the supply pump failed open
- Harness damage where the loom runs along the frame to the tank, from road debris or rodents
- Ground for the supply circuit corroded at its body or frame attachment point
- Pump internally frozen and physically damaged after a season without working purge cycles
- Previous splice or aftermarket repair in the tank harness corroded through
Symptoms
- Check engine light on with the engine running normally
- SCR, DEF or exhaust system message with a distance countdown
- No pump sound at the tank after switching the engine off, on a vehicle that normally purges
- A cluster of reductant pressure, flow and quantity codes stored together
- Reductant level not falling over hundreds of miles of driving
- Inducement warnings and staged power reduction as the countdown expires
- Split or weeping reductant lines discovered after a cold spell
- Crystalline white residue around line fittings or the doser
- Fault present from the first key cycle after a fuel filter, tank or sender repair
- SCR efficiency or NOx conversion code appearing weeks later
Diagnostic steps
- 1.Establish what this circuit supplies on this vehicle — reductant fluid on an SCR system, or fuel to a downstream injector on some regeneration systems. The rest of the diagnosis depends entirely on the answer, and the wrong assumption sends you to the wrong end of the vehicle.
- 2.Switch the engine off and listen at the tank. On a system that purges at shutdown this is a free, full-power command event, and silence where there should be a run is consistent with the open this code describes.
- 3.Read every stored code and their freeze-frame data before condemning anything. Supply sits upstream of pressure and dosing, so an accompanying cluster is usually consequence rather than a set of separate failures.
- 4.Check the fuse and relay for the supply circuit first. An open fuse is the cheapest possible answer and takes thirty seconds to eliminate.
- 5.Command the pump with a bidirectional tool while watching for any current flow at the connector. No current with a command present confirms the open rather than inferring it.
- 6.Back-probe the tank header connector for supply and ground with the pump commanded, and measure across the pump terminals for winding continuity.
- 7.Check continuity on the control wire from the module connector to the header connector with both ends disconnected, which removes the module and the pump from the result.
- 8.Inspect the header connector closely if the vehicle has recently had tank, filter, heater or level sender work — that connector is unplugged for all of those jobs and an unseated one is a common aftermath.
- 9.Walk the harness along the frame with the vehicle on a lift, looking for rodent damage, chafe at brackets and crush damage where the loom passes a suspension component.
- 10.After repair, command the pump, confirm it primes and builds pressure, then verify a purge cycle occurs at key-off before returning the vehicle in a climate where freezing matters.
Repair cost
$130 – $1,800
Diagnosis is $120 to $250. A fuse or relay is $20 to $110. Repairing an open in the tank harness or reseating a corroded header connector runs $150 to $500, at the higher end when the section is under the vehicle and needs lift time. The supply pump itself is rarely sold alone: on most designs it is part of the tank header or delivery module, so parts land between $250 and $900 and labour between 1.5 and 4 hours because the tank usually has to be drained and often dropped. Add $150 to $700 if a winter without working purge cycles has split lines or damaged the doser, which is the specific avoidable cost of leaving this code unrepaired in a cold climate. Module driver failure is uncommon and adds $600 or more with programming.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with def / scr reductant system 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.