Powertrain, generic (extended)

P2CD8 Turbocharger/Supercharger Boost Sensor D Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2CD8 is stored when the voltage from boost sensor D falls below the lowest value a healthy sensor can output. Since these sensors rise in voltage as pressure rises, a reading near zero almost always points to the electrics: signal shorted to ground, an interrupted 5 V supply, or a broken signal wire that the module pulls low. No manufacturer publishes limits for sensor D. For sensor A, Ford's 2024 petrol engines use under 0.19 V held for 5 s, and the GM-developed Saab 2.0 turbo under 0.09 V for more than 5 s as a Type B fault. If other 5 V sensors report low at the same moment, the shared reference circuit is the first suspect. The module then stops regulating boost on that path. Too high is P2CD9.

Likely causes

Signal wire of sensor D shorted to ground
5 V reference to the sensor open or shorted
Sensor D internally failed with output stuck low

Symptoms

  • Warning lamp on
  • Only base boost available, clear loss of power
  • Live data shows sensor D at or near minimum pressure even under load

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–350
Time0.3–2 h

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

Parts involved

boost pressure sensor dwiring harnessecm

Related codes

P2CD6P2CD7P2CD9P25F4P0237P0241

References: law.cornell.edu, fordservicecontent.com, saabwisonline.com.