P2048
Reductant Injection Valve Circuit Low Bank 1 Unit 1P2048 is a generic OBD-II powertrain diagnostic trouble code: Reductant Injection Valve Circuit Low Bank 1 Unit 1. It is logged by the engine control unit when the scr/adblue monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P2048 means
P2048 — Reductant Injection Valve Circuit Low Bank 1 Unit 1 — is an SAE generic code indicating that the electrical circuit supplying the AdBlue dosing injector (the injector valve that sprays atomised urea solution into the exhaust pipe upstream of the SCR catalyst) has developed a low-voltage or short-to-ground fault. Bank 1 Unit 1 refers to the primary dosing injector on the Bank 1 exhaust side, which is the standard single-injector configuration on most passenger car and light commercial SCR systems.
The dosing injector is a solenoid-actuated valve opened by a pulse-width-modulated signal from the SCR control module. The circuit is monitored for current draw; a lower-than-expected current (which appears as a low-voltage condition at the driver output) typically indicates an open circuit — a broken wire, failed solenoid coil, or disconnected connector. A short to ground can also present as circuit low depending on the driver architecture. When this fault is active, the injector cannot dose, and the SCR catalyst receives no reductant, rapidly degrading NOx conversion efficiency to near zero.
On diesel vehicles subject to NOx countermeasure strategies (Euro 5b/6), failure of the dosing injector circuit triggers the MIL and begins the NOx exceedance fault accumulation counter. After a defined number of fault events, the ECM initiates a progressive torque derate leading eventually to a speed-limited state.
Common causes
Most-frequently reported root causes when P2048 is logged.
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1
Open circuit in the dosing injector wiring — broken wire or corroded connector at the injector
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2
Failed injector solenoid coil (open winding)
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3
Damaged wiring harness in the high-temperature area near the exhaust system
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4
Failed SCR dosing module output driver
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5
Short to ground in the injector supply circuit
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6
Injector connector not fully seated after previous maintenance
Symptoms drivers notice
How to diagnose P2048
A typical diagnostic flow when this code is present.
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1
Read all fault codes and note companion codes — P2047 (circuit high), P208E (stuck closed), or NOx sensor codes help distinguish electrical from mechanical injector failures
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2
Locate the AdBlue dosing injector on the exhaust pipe and inspect the connector for heat damage, corrosion, or disconnection
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3
Measure injector solenoid resistance across the injector terminals with the connector unplugged; compare to manufacturer specification — an open circuit (infinite resistance) confirms a failed solenoid
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4
With the ignition on (pump running), measure the voltage at the injector connector harness side — confirm the SCR module is providing drive signal
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5
Inspect the wiring loom from the dosing module to the injector for chafing against exhaust heat shields
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6
Replace the dosing injector if solenoid resistance is out of specification; ensure the replacement injector is calibrated or coded to the SCR module as required by the manufacturer
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7
After repair, clear codes and use a scan tool with SCR actuator test capability to command a test dose and verify current draw is within specification
Related powertrain codes
- B0001 — PCM Discrete Input Speed Signal Error
- B0004 — PCM Discrete Input Speed Signal Not Present
- C0359 — Four Wheel Drive Low Range (4LO) Discrete Output Circuit
- C0362 — 4LO Discrete Output Circuit High
- P2000 — NOx Adsorber Efficiency Below Threshold Bank 1
- P2001 — NOx Adsorber Efficiency Below Threshold Bank 2
Frequently asked questions
Can I drive indefinitely with P2048?
No. Without a functioning dosing injector, the SCR system does not convert NOx. On Euro 5b/6 vehicles this triggers the NOx countermeasure countdown. After the allowed number of fault cycles, the ECM will progressively derate engine power.
Does P2048 mean the injector must be replaced?
Not necessarily. A broken wire or corroded connector at the injector is a common cause. Always verify wiring integrity before replacing the injector itself.
Is the dosing injector serviceable or is the entire dosing module replaced?
On most passenger car platforms, the dosing injector is a separate replaceable component. On some integrated dosing pump/injector units (common on trucks), the whole module is replaced. Consult the manufacturer parts diagram.
After replacing the injector, does it need to be coded to the vehicle?
On some manufacturers (notably Mercedes-Benz and certain BMW BlueTEC platforms), the injector requires a calibration value to be written to the SCR control module via a dealer tool. Check the manufacturer service procedure before assuming a straight-swap repair is complete.
Disabling P2048 in software
RaceTune can permanently disable P2048 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
ECUs with a P2048 disable in our catalogue
Confirmed coverage from our recipe database — we support many more families. Upload your file and our identifier will match it automatically.
- Bosch EDC17C60 verified 2 software versions
- Bosch MD1CP004 verified 1 software version
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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