Faulty or worn mode switch with an internal short or contamination; Signal wire chafed or shorted to earth in the switch circuit or harness; Corroded, damaged or water-contaminated connector at the switch or control unit; Switch stuck in the pressed position, or spilled liquid inside the switch or console; Open or poor reference supply or earth giving a low reading; Faulty transmission control unit or body control module input; Outdated control unit software where the manufacturer has issued a known fix.

P07D2

Transmission Mode Switch E Circuit Low.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
7: AreaTransmission
D2: FaultThe specific fault in that area

What it means

P07D2 means the transmission control unit has detected a low voltage or signal in the circuit of Transmission Mode Switch E, which is the driver-selectable mode input such as sport, economy, snow or tow. The control unit saw the switch signal sit below the expected range, which points to a short to earth, a faulty switch or a wiring fault. Which switch is 'E' and what mode it selects depends on the model and gearbox, so check the manufacturer wiring information.

Symptoms

Gearbox warning light or engine management light on
Selected drive mode does not engage or does not change
Gearbox stuck in a default or standard shift programme
Mode indicator on the dash missing, flickering or wrong
Shifts feel different from normal, or harsher than usual
Code may come and go with switch movement or road vibration

Possible causes

Faulty or worn mode switch with an internal short or contaminationlikely
Signal wire chafed or shorted to earth in the switch circuit or harnesslikely
Corroded, damaged or water-contaminated connector at the switch or control unitpossible
Switch stuck in the pressed position, or spilled liquid inside the switch or consolepossible
Open or poor reference supply or earth giving a low readingpossible
Faulty transmission control unit or body control module inputrare
Outdated control unit software where the manufacturer has issued a known fixrare

How to diagnose

Read all stored codes and freeze frame data, noting whether the fault is current or historic, then check for related network or switch codes
Check the mode switch operation and the dash mode indicator, and look for a stuck, sticky or liquid-contaminated switch
Inspect the switch connector and harness for damage, corrosion, moisture, chafing or pin tension problems
Use live data to watch the switch input state or voltage while operating the switch, and see whether it changes or stays low
Wiggle the harness and connector while watching live data to find intermittent faults
Check the reference supply and earth at the switch against the wiring diagram for your model
Test the circuit for a short to earth and for resistance, with the connectors disconnected, per the manufacturer procedure
Check for any software updates or service bulletins for your model, then clear the code and road test to confirm it does not return

How to fix

Replace the mode switch if it is faulty, stuck or contaminated
Repair or replace the damaged wiring where a short to earth is found
Clean, repair or replace corroded or damaged connectors and terminals
Dry out and clean any liquid ingress and fix the cause of the leak
Restore a faulty supply or earth connection in the circuit
Update the control unit software only where a known fault is documented for that issue, or replace the control unit if it is proved faulty

Can I keep driving?

Low severity

The car can usually be driven normally, as the gearbox typically falls back to a default mode. Book it in soon, and avoid driving if shifting becomes harsh, erratic or stuck in a gear.

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