P2E18: Intermediate Shaft Selection Actuator Position Sensor Circuit High

What it means

The ECM detects a circuit high fault on the intermediate shaft selection actuator position sensor. Reading cannot be used reliably for control.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

The intermediate shaft selection actuator position sensor reports the shaft position to the control module. This code sets when its signal is too high for reliable use, which can occur if the signal wire contacts battery voltage, the sensor is open, or the connector has excessive resistance.

Common causes

Most likely first.

1. Signal wire shorted to B+
2. Open sensor
3. Connector pins corroded - high contact resistance

Symptoms

• Check-engine or transmission warning light
• Delayed or failed gear changes
• Transmission may stay in one gear or enter a limited-operation mode

How to diagnose it

1. Save freeze-frame data and compare live intermediate shaft position with the requested position, looking for a reading fixed high.
2. Inspect the sensor connector and signal wire for corrosion, loose pins, damaged insulation, or contact with a B+ feed.
3. Check the sensor's supply and ground against the wiring diagram and manufacturer's specification.
4. With the circuit isolated as directed by the manufacturer, test for a signal wire short to B+ and check circuit continuity.
5. If wiring checks pass, test the sensor output and replace the sensor if it is open or outside the manufacturer's specification.

Common fixes

• Clean and secure corroded or loose sensor connector pins.
• Repair the signal wire where it is shorted to battery voltage.
• Replace an open or failed intermediate shaft position sensor.
• Clear the code and verify the reported position tracks actuator movement.

Can I keep driving?

Do not continue normal driving if the transmission is stuck in one gear, shifts poorly, or enters limited operation; it may not respond reliably when you need to accelerate. If it operates normally, limit driving and have the high signal fault diagnosed soon.