P07D3: Transmission Mode Switch E Circuit High

What it means

The control module monitors the transmission mode switch E circuit signal. It sets this code when the signal is higher than the expected range.

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. P07D3 sets when the E signal rises above its expected range, which may indicate a short to battery voltage or a damaged supply wire contacting the signal.

Common causes

Most likely first.

1. Switch wire shorted to battery voltage
2. Connector pins corroded - high contact resistance
3. Supply wire pinched against B+ source

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. Record freeze-frame data and compare mode switch E live data with the selected mode to establish when the high signal occurs.
2. Inspect the E-circuit harness for pinching or damage near powered wiring or other battery-voltage sources.
3. Check the E connector for corrosion, loose pins, or terminals that could bridge the signal to a power feed.
4. Use the wiring diagram to test the E signal for a short to battery voltage and check circuit continuity.
5. If wiring and connections pass, test the E switch and module input using the manufacturer's procedure.

Common fixes

• Repair E-circuit wiring pinched against a power source.
• Clean or repair corroded or damaged connector terminals.
• Replace the mode switch E if it fails its specified test.
• Repair the module input circuit if tests isolate the high signal to that point.

Can I keep driving?

If shifting is erratic, slipping, or restricted to one gear, avoid continued driving because slipping can damage the transmission. If it shifts normally, use the vehicle only for a short, cautious trip to diagnosis.