Powertrain, generic (extended)

P2048 Reductant Injection Valve Circuit Low (Bank 1 Unit 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2048 means the control line of the Bank 1, unit 1 DEF injector is pulled toward ground, typically a chafed wire touching the chassis or an internal short in the coil. GM's LML calibration treats less than about 0.5 ohm between signal and ground for 2 s as a failure (Type A). Ford's 2023 diesel logic reports the code once injector current exceeds 1.6 A; Deutz's EMR5 list files it under voltage below normal on the metering unit. Nissan reflashed the ECM of the 2016 to 2019 Titan XD with the Cummins 5.0 L V8 because P2048 appeared without a real defect, and Volvo traced it to a harness rubbed through on VNR trucks. While the code is active, dosing is normally blocked; the catalyst no longer reduces NOx and the inducement countdown may begin.

Likely causes

Control wire chafed against chassis or exhaust bracket
Shorted winding inside the DEF injector
ECM software setting the code without a fault (Nissan Titan XD reflash)
DEF residue or water bridging the connector pins

Symptoms

  • MIL on
  • DEF dosing suspended, warning in the instrument cluster
  • Inducement or reduced power after a countdown

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–900
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

reductant injection valve

Related codes

P2047P2049P2051P2054

References: gsi.ext.gm.com, fordservicecontent.com, serdia.deutz.com, static.nhtsa.gov.