P1806: Transmission 4-Wheel Drive High Indicator Short Circuit To Battery
MediumPowertrainTransmission
What does P1806 mean?
P1806 is a diagnostic trouble code indicating "Transmission 4-Wheel Drive High Indicator Short Circuit To Battery". The ECU is detecting a voltage reading that is below the expected range in the transmission circuit. This typically points to a wiring short, a faulty sensor, or a grounding issue.
Symptoms you may notice
- Check engine light (MIL) illuminated on dashboard
- Harsh or delayed gear shifts
- Transmission slipping
- Vehicle stuck in one gear (limp mode)
- Intermittent warning lights
Estimated repair cost
Typical range in Australia (parts + labour)
$300 – $3000 AUD
Common causes
- Damaged or corroded wiring harness
- Loose or disconnected electrical connector
- Failed transmission sensor or actuator
- Blown fuse in the related circuit
- Poor ground connection
What should you do?
This code sits in the exterior lighting. Nothing about how the car drives changes, but how easily other road users see you does, and a light out is an on-the-spot fine and an inspection failure. Worth sorting before you next drive at night.
Get a diagnosis for YOUR car
Code P1806 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.