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

P05D3 Driver Mode Select Switch A Range/Performance

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. P05D3 means the voltage lies between the low and high limits but in a dead band between two valid positions, so no position is clear – at GM for example 1.327–1.427 V or 2.967–3.348 V (petrol) and 0.528–0.628 V (diesel). Typical are contact resistance shifting all steps or a rotary switch resting between two detents.

Likely causes

Corroded connector or increased contact resistance
Switch worn or detent unclear (knob between two positions)
Moisture in the switch
Ground offset at the switch

Symptoms

  • Selected mode not taken over or jumping
  • Check engine light (GM after two trips)
  • Mode display missing

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

P05D0P05D1P05D2P05D7

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