Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P05D2 Driver Mode Select Switch A Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

The driver mode select switch (tour, sport, eco, snow, off-road, towing) changes engine and transmission maps such as shift points, pedal map and cylinder deactivation, so CARB requires it to be monitored as an input. GM reads switch A as an eight-position resistor ladder in the body module and sets P05D1–P05D3 in its 2025 tables when a condition is present for 4 s within 5 s, type B with warning lamp after two trips. A fault blocks mode selection; the vehicle stays in its basic mode. P05D2 means the signal is above the highest valid window: GM petrol above 4.36 V, diesel above about 4.72 V. With a pull-up this usually means an open signal or switch ground, otherwise a short to positive.

Likely causes

Signal or ground line open, connector off at the switch
Switch faulty (track interrupted)
Signal line shorted to positive
Body module

Symptoms

  • Drive mode cannot be changed, vehicle stays in normal mode
  • Mode display missing or jumping back
  • Check engine light (GM after two trips)

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–350
Time0.5–1.5 h

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

Parts involved

drive mode switchswitch wiringbody control module

Related codes

P05D0P05D1P05D3P05D6

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