Powertrain, generic · Auxiliary emission controls

P04E1 Crankcase Ventilation Hose Connection Sensor Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

The crankcase ventilation (PCV) system routes blow-by gas from the crankcase into the intake; CARB requires a disconnection between crankcase and intake to be detected. GM's 2.0-litre LSY has a pressure sensor in the PCV hose: with the hose connected it must see a pressure drop that grows with air flow, plus pressure pulses from the pistons. Ford reports the same sensor type as crankcase pressure sensor A (P051A ff). P04E1 is the sensor's general circuit fault, typical of digital sensors with invalid signal patterns or where low and high are not separated. Its circuit diagnosis is a precondition for the disconnection check P04DB. No manufacturer document available to us uses P04E1 itself; GM uses P04E2/P04E3, Ford P051A ff.

Likely causes

Sensor connector not latched or corroded
Signal, 5 V reference or ground wire open
Sensor faulty
Engine module

Symptoms

  • Check engine light on
  • Disconnection check P04DB does not run
  • Usually no change in driving

Repair estimate

DifficultyEasyDIY possible
Parts and labour€50–250
Time0.3–1.5 h

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

Parts involved

crankcase ventilation hose sensorsensor wiringengine control module

Related codes

P04E2P04E3P04E4P04FBP04DBP051A

References: gsi.ext.gm.com, fordservicecontent.com, law.cornell.edu.