P260B: PTO Control Circuit Low

What it means

Voltage on the PTO engagement control line is below the expected window. Usually a short to ground or a shorted solenoid coil.

At a glance

• Usually lights the check-engine light

How it works

The PTO engagement control circuit operates a solenoid that connects an engine-driven accessory on equipped commercial vehicles. The controller monitors the control-line voltage and sets P260B when it is below the expected range, commonly because the wire is shorted to ground or the solenoid coil is shorted. The PTO may fail to engage, and its indicator may not reflect actual operation.

Common causes

Most likely first.

1. Control wire shorted to ground
2. Internal short in the solenoid coil
3. Connector pins corroded - high contact resistance

Symptoms

• Check-engine light
• PTO may not engage
• PTO indicator may not reflect PTO operation

How to diagnose it

1. Check scan-tool PTO command and status data and record whether the low reading occurs during an engagement request.
2. Secure the vehicle and inspect the PTO control wiring and solenoid connector for chafing to ground, corrosion, moisture, or loose pins.
3. Following the manufacturer's isolation procedure, test the control wire for a short to ground.
4. Test the PTO solenoid coil for an internal short using the manufacturer's procedure.
5. If those checks pass, assess connector contact condition and circuit voltage under command to find excessive resistance or another wiring fault.

Common fixes

• Clean and secure corroded PTO circuit connector pins.
• Repair wiring shorted to ground.
• Replace the PTO solenoid if its coil is internally shorted.
• Repair a high-resistance connection identified in the control circuit.

Can I keep driving?

Driving is generally possible if the PTO is not needed and the vehicle runs normally, but the PTO may not engage reliably. Do not operate PTO equipment until the fault is repaired and engagement can be confirmed.