Faulty high speed fan relay (internal coil open or shorted); Damaged, chafed or corroded wiring in the relay control circuit between the relay and the powertrain control module; Poor connection or corrosion at the relay socket or in the power distribution centre terminals; Blown fuse or loss of power supply feeding the relay; Connector or terminal damage at the powertrain control module; Faulty powertrain control module relay driver.

P1489

High Speed Fan CTRL Relay Circuit Open Or Shorted.

Jeep
Powertrain
Manufacturer code
Medium severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
4: AreaAuxiliary emission controls
89: FaultThe specific fault in that area

What it means

P1489 on a Jeep means the powertrain control module has detected a fault in the control circuit for the high speed radiator fan relay. The module monitors the relay driver and saw a voltage or state that did not match what it commanded, which points to an open circuit or a short in the relay control side.

Symptoms

Engine temperature rising or overheating in traffic or when idling
Warning light on the dash for the engine management system
Air conditioning performing poorly at idle or in slow-moving traffic
Radiator fan not running at high speed, or running constantly
Temperature gauge climbing when stationary and falling when moving

Possible causes

Faulty high speed fan relay (internal coil open or shorted)likely
Damaged, chafed or corroded wiring in the relay control circuit between the relay and the powertrain control modulelikely
Poor connection or corrosion at the relay socket or in the power distribution centre terminalslikely
Blown fuse or loss of power supply feeding the relaypossible
Connector or terminal damage at the powertrain control modulepossible
Faulty powertrain control module relay driverrare

How to diagnose

Read the stored codes and freeze frame data, and note whether other fan or cooling codes are present
Check the fuses and the relay for the high speed fan using the wiring diagram for the specific model and engine
Inspect the relay socket, connector and terminals for corrosion, heat damage or looseness
Swap the relay with a known good one of the same type, or bench test the coil resistance against specification
Command the fan on with a scan tool where supported and listen for the relay click and fan operation
Check the relay control wire for continuity, short to ground and short to voltage between the relay and the powertrain control module
Check the relay power and ground supplies with a multimeter under load
Inspect the powertrain control module connector pins before considering the module itself

How to fix

Replace the high speed fan relay if it fails testing
Repair or replace damaged wiring in the relay control circuit
Clean or replace corroded relay socket terminals or connectors
Replace the blown fuse after finding and correcting the cause of the overload
Repair the connector terminals at the powertrain control module
Replace or repair the powertrain control module only after all wiring and relay checks are proven good

Can I keep driving?

Medium severity

The car can be driven short distances with care, but with no high speed fan there is a risk of overheating in traffic or at idle. Watch the temperature gauge closely and get it repaired soon, and stop if the temperature rises.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.