Powertrain, generic (extended)

P279E Four Wheel Drive (4WD) Range Signal Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P279E flags a 4WD range signal that is electrically present but does not make sense: it may show a range the transfer case cannot be in, jump between high, low and neutral without a request, or contradict what the speed ratio across the transfer case shows. Such a plausibility check typically compares the reported range with commanded shifts and with the measured ratio monitored by P279A to P279C. No manufacturer documents P279E publicly with set conditions; GM's 2008 Two-Mode Hybrid control module shows how the same range information is validated by its circuit code P279D, and CARB 13 CCR 1968.2 requires rationality checks for such inputs. Causes are a misadjusted or worn range sensor, a shift motor stopping between positions, or wiring that intermittently loses contact.

Likely causes

Worn or misadjusted transfer case range sensor
Transfer case shift motor stopping between ranges
Intermittent contact in the range signal wiring

Symptoms

  • 4WD indicator shows a range that does not match the actual drive
  • Range shifts refused or completed only partly
  • Warning lamp

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–1,200
Time0.5–4 h

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

Parts involved

four wd range sensortransfer case

Related codes

P279DP279FP27A0P279C

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