Powertrain, generic (extended)

P203A Reductant Level Sensor A Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P203A is the general circuit code for reductant level sensor A, the first or only fill level element inside the DEF tank. Deutz lists it for the EMR L1 main and secondary ECU: the tank level input (J1939 SPN 1761) stores P203A with failure type 13 when the line is interrupted and with types 21 or 22 when the value drops under or climbs over its valid range. VW's 2014 Touareg (engine CNRB) files a gap of more than 80 s between watchdog pulses under P203A, even though VW's chart labels the code Circuit Low. FCA counts P203A among the faults that put the 6.7L Ram into the Service DEF – See Dealer inducement message. Low and high faults of the same sensor have their own codes P203C and P203D; sensors B and C use P21A8 and P21AD. Drivers get a DEF warning and, left alone, the usual speed or restart limits.

Likely causes

Loose, corroded or DEF-contaminated connector at the tank module
Broken or chafed level sensor wiring between tank and control unit
Failed level sensor or level electronics in the tank unit
Fault in the dosing or engine control unit, sometimes fixed by software

Symptoms

  • MIL and DEF system warning in the cluster
  • DEF level gauge missing, frozen or wrong
  • Countdown to speed limit or no-restart after some distance

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–1,200
Time0.5–3 h

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

Parts involved

reductant level sensorreductant tank

Related codes

P203BP203CP203DP203EP21A8P21AD

References: serdia.deutz.com, serdia.deutz.com, static.nhtsa.gov, static.nhtsa.gov.