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

P05D0 Driver Mode Select Switch A Circuit

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. P05D0 is the general circuit fault of switch A without low/high assignment. No manufacturer document available to us uses it; GM covers the same switch with the more specific P05D1–P05D3.

Likely causes

Connector at the switch or control panel corroded or loose
Switch faulty, e.g. liquid in the centre console
Wire to the reading module open
Reading 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

P05D1P05D2P05D3P05D4P05C7

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