Powertrain, generic (extended)

P24CE Reductant Tank Cap Switch Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

With P24CE the controller sees the DEF cap switch signal above its permitted band. On a pull-up input this typically happens when the line is open, because the input then floats up to the reference, or when it touches a supply wire; a broken switch contact can look the same. Unlike P24CD, a simple unplugged connector after tank work is a frequent trigger here. No manufacturer documents P24CE publicly. The switch itself is known from Audi's bulletin 2051053 for the 2013 to 2015 Q7 TDI, which deals with the related codes P24CB and P24CC and places the switch on the filler neck of the active tank. CARB's comprehensive component rules call for detecting such out-of-range inputs. Checking the plug and measuring the line with the switch operated settles it.

Likely causes

Disconnected plug or broken wire letting the input float high
Signal wire touching a supply line
Broken contact inside the switch

Symptoms

  • Malfunction indicator lamp on
  • Refill of DEF not registered

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–600
Time0.3–3 h

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

Parts involved

reductant tank cap switch

Related codes

P24CBP24CCP24CDP24CF

References: law.cornell.edu, static.nhtsa.gov.