Powertrain, generic (extended)

P2C28 Fuel Injector Group B Supply Sense Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2C28 is set when the sense line of the injector group B supply shows more voltage than allowed – either above the upper limit while the group is switched on, or voltage present while the module has switched the group off. Common reasons are a welded injector relay, a supply wire chafed against another powered circuit, or a sense wire shorted to battery voltage. A supply that cannot be switched off matters because the module can no longer isolate the group when it needs to protect an injector or the catalyst. No publicly accessible manufacturer document covers P2C28; it follows CARB's demand for separate high-range codes, and GM's handling of injector supply faults on the Saab 9-5 2.0T (wrong voltage for over 1 s, Type B, injector disabled) gives a comparable logic.

Likely causes

Injector relay contacts stuck closed
Sense or supply wire shorted to battery voltage
Excessive system voltage from the charging system
Internal fault of the supply switch in the engine control module

Symptoms

  • Check engine light
  • Often no noticeable change in running
  • Battery drain if the relay stays closed after switch-off

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€30–600
Time0.3–3 h

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

Parts involved

fuel injector group bwiring harnessecm

Related codes

P2C26P2C27P2151P2149P0687

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