Powertrain, generic · Computer and auxiliary outputs

P06D4 Sensor Reference Voltage E Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

The engine module feeds sensors from several regulated 5 V reference circuits; a short at one sensor pulls the whole circuit down and all its sensors report at once – unplug them one by one to find the culprit. P06D4 means reference E is too high – often a sensor signal wire shorted to 12 V. No manufacturer document available to us names P06D4 itself; Ram's 6.7 L Cummins uses the neighbouring P06D3, and GM reports circuit E under P06D2. Sensors on the circuit then read too high.

Likely causes

Reference or sensor signal wire shorted to 12 V
Chafing or water in harness or connector
A connected sensor faulty internally
Module internal voltage regulator or components

Symptoms

  • Check engine light
  • Several sensor codes at once
  • Reduced power or limp mode
  • Possibly starting problems

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time1–3 h

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

Parts involved

sensor reference voltage circuitsensor wiringengine control module

Related codes

P06D2P06D3P06D5P0643P06D8

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