P0953: Auto Shift Manual Control Circuit High

What it means

The auto-shift manual control circuit reports a high condition. Manual mode shift requests cannot be reliably interpreted.

At a glance

• Usually lights the check-engine light

How it works

The auto-shift manual control circuit carries the driver's gear requests to the control module. P0953 sets when the input remains electrically high beyond the expected state, which can result from a wire shorted to battery voltage, a switch stuck open, or a poor connector contact.

Common causes

Most likely first.

1. Wire shorted to B+
2. Switch stuck open
3. Connector pins corroded - high contact resistance

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 monitor the manual control input to see whether it stays high across control positions.
2. Inspect the switch connector and harness for loose or corroded pins, damaged insulation, and contact with a powered wire.
3. Operate the switch while watching live data to check whether the input changes from its high state.
4. Use the vehicle wiring diagram to test for a short to battery voltage and verify the switch circuit's continuity.
5. If the wiring and switch behave correctly, check the module input according to the manufacturer's diagnostic information.

Common fixes

• Secure or clean a loose or corroded manual control connector.
• Repair a signal wire shorted to battery voltage.
• Replace a switch that remains open when operated.
• Repair a confirmed module input fault.

Can I keep driving?

Manual gear requests may be unavailable or misread, although normal automatic operation may continue. Avoid relying on manual mode, and stop driving if the transmission begins slipping, shifting harshly, or locking into one gear.