P2D89: Fan 1 Control Module Supply Voltage Circuit

What it means

The supply voltage circuit of the fan 1 control module reports a fault. Module may not start or operate correctly.

At a glance

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

How it works

Fan 1's control module needs a stable supply voltage to start and operate the first cooling fan. P2D89 sets when the module's supply circuit is faulty, so the fan may stop, fail to start, or work intermittently.

Common causes

Most likely first.

1. Module supply fuse blown
2. Wiring or connector fault

Symptoms

• Check-engine or cooling-system warning light may be on
• Cooling fan may not run or may operate intermittently
• Engine temperature may rise

How to diagnose it

1. Record freeze-frame data and check whether fan 1 was commanded on when its supply fault occurred.
2. With the vehicle off, inspect the fan 1 module's supply fuse, connector, and harness for a blown fuse, loose terminals, corrosion, or wiring damage.
3. Check the module's ground and supply connections for secure contact and damage.
4. Measure supply voltage at the fan 1 module under the manufacturer's test conditions, including when the fan is commanded on, and compare it with the manufacturer's specification.
5. If the fuse is blown, identify and correct the cause of the overload or short before replacing the fuse and retesting.

Common fixes

• Replace a blown fan 1 module supply fuse after checking for the cause.
• Clean and secure corroded or loose supply or ground terminals.
• Repair damaged supply wiring or a short in the fan 1 module circuit.
• Replace the fan 1 control module if its supply and ground are correct but it still fails to operate.

Can I keep driving?

The first cooling fan may not run, so avoid traffic, hot conditions, and heavy loads if engine temperature is rising. Stop safely if a temperature warning appears or the engine begins to overheat.