P2B69: Coolant Pump D Supply Voltage Circuit

What it means

Coolant pump D reports a supply voltage circuit condition. Coolant circulation through the affected loop cannot be commanded reliably.

At a glance

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

How it works

Coolant pump D needs a supply-voltage feed to operate and circulate coolant through its loop. The module monitors that feed and sets P2B69 when the pump’s supply circuit has a fault, such as a blown fuse or a wiring or connector problem that prevents reliable power delivery.

Common causes

Most likely first.

1. Supply fuse blown
2. Wiring or connector fault

Symptoms

• Check-engine light
• Engine or a coolant-cooled component may run hotter than usual
• Cabin heat or cooling performance may be reduced

How to diagnose it

1. Record freeze-frame data and check live pump D command and supply status to determine whether the fault occurs when the pump is requested.
2. With the system cool, inspect pump D’s supply wiring and connector for looseness, corrosion, heat damage, or a broken wire.
3. Check the pump D fuse and verify that the correct supply reaches the fuse and pump connector under the commanded conditions.
4. Test the supply wire and connector for continuity and excessive resistance, comparing results with the manufacturer’s specification.
5. If supply wiring checks out, confirm pump D’s power and ground under load before replacing the pump.

Common fixes

• Replace a blown pump D supply fuse after checking for a short or overload that caused it to fail.
• Clean, secure, or repair a loose or corroded supply connector.
• Repair damaged or open supply wiring to pump D.
• Repair a poor power or ground connection that fails under load.

Can I keep driving?

Limit driving and watch the temperature gauge; stop if the engine or a coolant-cooled component gets hot, or if a coolant warning appears. Loss of pump D supply can reduce circulation and lead to overheating.