Faulty driver mode select switch B (internal fault or stuck contacts); Damaged, corroded or loose connector at the switch or control unit; Open circuit in the signal or ground wire, letting the signal float high; Signal wire shorted to a voltage supply; Liquid ingress or contamination in the switch assembly or centre console; Fault in the control unit that reads the switch, or a software issue.

P05D6

Driver Mode Select Switch B Circuit High.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
5: AreaVehicle speed, idle control and auxiliary inputs
D6: FaultThe specific fault in that area

What it means

P05D6 is a generic code meaning the control unit has detected a high voltage on the circuit for driver mode select switch B. The switch lets the driver choose a drive mode such as eco, sport or normal. The module saw a signal voltage above the expected range, which can mean a short to voltage, an open circuit that lets the signal float high, or a faulty switch.

Symptoms

Drive mode selector not responding or not changing modes
Car stuck in a default drive mode
Warning light or message about drive mode or a system fault
Changes in throttle response, gearshift behaviour or steering feel
Mode indicator on the dash or switch not lighting or showing wrongly

Possible causes

Faulty driver mode select switch B (internal fault or stuck contacts)likely
Damaged, corroded or loose connector at the switch or control unitlikely
Open circuit in the signal or ground wire, letting the signal float highpossible
Signal wire shorted to a voltage supplypossible
Liquid ingress or contamination in the switch assembly or centre consolepossible
Fault in the control unit that reads the switch, or a software issuerare

How to diagnose

Read all stored and pending codes and note the freeze frame data, then check for other drive mode, network or supply voltage codes
Operate the mode selector and watch live data for the switch B state or voltage, and see whether it changes with each press
Inspect the switch, its connector and the wiring for damage, corrosion, moisture or signs of previous repair
Check for liquid spills or debris around the switch and console
Check the switch supply, signal and ground circuits against the manufacturer wiring diagram, as pin layout and expected voltages depend on the make and model
With the connector unplugged, test the signal wire for a short to voltage and the ground wire for continuity
Check the switch resistance or output in each position against the manufacturer specification
Check for any applicable software update for the control unit only after the wiring and switch have been proven good

How to fix

Replace the driver mode select switch if it is faulty or stuck
Clean, repair or replace corroded or damaged connector terminals
Repair open circuits or wiring shorted to voltage in the switch circuit
Dry out and clean the switch area, and replace the switch if moisture has damaged it
Replace or reprogram the control unit only if testing proves it faulty or the manufacturer lists an update for this fault

Can I keep driving?

Low severity

The car is normally safe to drive, as it will usually fall back to a default drive mode. Book it in soon, and stop if you notice odd gearbox, throttle or steering behaviour.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.