What does P1812 mean on a Ford?

P1812. Transmission 4-Wheel Drive Mode Select Circuit Failure. Applies to F-150, Super Duty, Explorer, Ranger.

What causes P1812 on a Ford?

Failed mode select switch Open mode select circuit Corroded switch connector Stuck switch contacts 4WD module fault

How do I fix P1812 on a Ford?

Test the mode switch in each position Check circuit continuity Inspect the connector Verify the module sees mode changes Replace the switch per test data

Code

P1812

Transmission 4-Wheel Drive Mode Select Circuit Failure

Category: Powertrain - Transmission
Severity: Check Engine Light
Applies to: F-150, Super Duty, Explorer, Ranger
Related: P0700 Transmission Control System Malfunction on OBD Codes List

Findings, check these first

Failed mode select switch
Open mode select circuit
Corroded switch connector
Stuck switch contacts
4WD module fault

Standard procedure

Test the mode switch in each position
Check circuit continuity
Inspect the connector
Verify the module sees mode changes
Replace the switch per test data

Code lookup

Type a code above, or start from a symptom or a common code.

Press / to jump to the box. Ford-enhanced powertrain, body, chassis and network codes. Generic P0xxx codes live on OBD Codes List.

Sources and review

Review: checked against the recorded source material.

OBDII.pro: P1812 Ford definition
live reference page (obdii.pro)
Supports: Ford-family meaning for P1812: Transmission 4-Wheel Drive Mode Select Circuit Failure
Fetched directly. obdii.pro is a publisher independent of the engine-codes family.
P1812 FORD Code: Meaning, Causes, and Symptoms | OBD2 Codes
live reference page (obd2-codes.co)
Supports: Ford meaning for P1812: Transmission 4-Wheel Drive Mode Select Circuit Failure
Fetched directly. obd2-codes.co phrasing matches the engine-codes family, so it counts as one publisher.

Last updated 2026-09-06.

Report a correction for P1812. Include your vehicle, the issue and a source if you have one.