P07D2: Transmission Mode Switch E Circuit Low

What it means

The transmission control module monitors the transmission mode switch E circuit voltage. It sets this code when the signal falls below the expected range, indicating an electrical low condition in that circuit.

At a glance

• Usually lights the check-engine light

How it works

The transmission mode switch E is an electrical input the transmission control module uses to recognize a selector or drive-mode state. P07D2 sets when the E signal falls below its expected range, pointing to a low-signal condition such as a short to ground or damaged wiring.

Common causes

Most likely first.

1. Switch wire shorted to ground
2. Connector pins corroded - high contact resistance
3. Harness chafing through insulation

Symptoms

• Check engine or transmission warning light on
• Harsh, delayed, or missing shifts
• Possible limp mode (locked in one gear)
• Slipping or shuddering during gear changes

How to diagnose it

1. Save freeze-frame data and check mode switch E live data to confirm the low reading and the selector state at the time.
2. Inspect the E-circuit harness for chafing or insulation worn through where it could touch ground.
3. Check the E-circuit connector for corrosion, loose pins, or poor contact.
4. Use the wiring diagram to test for a short to ground and verify continuity from the E switch to the transmission control module.
5. If the circuit checks out, test the mode switch E and module input using the manufacturer's procedure.

Common fixes

• Repair E-circuit insulation damaged by chafing against ground.
• Clean or repair corroded or loose E-circuit terminals.
• Replace the mode switch E if it fails testing.
• Repair the module input circuit if the wiring and switch test correctly.

Can I keep driving?

Avoid long trips or heavy loads if the transmission shifts harshly, slips, or stays in one gear; continued slipping can worsen internal damage. If it shifts normally, keep driving limited and cautious until the fault is diagnosed.