Skip to content
GTECH Calibration
Portal

P1490

Low Speed Fan CTRL Relay Circuit Open Or Shorted.

  • Dodge
  • Powertrain
  • Manufacturer code
  • Medium severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
4
AreaAuxiliary emission controls
90
FaultThe specific fault in that area

What it means

On Dodge vehicles, P1490 means the powertrain control module has detected a fault in the low speed radiator fan control relay circuit. The PCM commands the relay on and off and monitors the circuit, and it saw an open circuit or a short that did not match the commanded state. The exact relay layout and fan arrangement depend on the model and engine.

Symptoms

  • Engine temperature gauge climbing at idle or in traffic
  • Radiator fan not running, or running constantly
  • Air conditioning performing poorly when stationary
  • Malfunction indicator lamp on
  • Engine overheating or coolant warning in slow traffic

Possible causes

  • Faulty low speed fan control relay (coil open or shorted, or contacts stuck)likely
  • Damaged, chafed or corroded wiring between the relay, fuse and PCMlikely
  • Corroded or loose connector terminals at the relay base, fan or PCMpossible
  • Blown fuse or fusible link in the relay power supplypossible
  • Failed fan motor or fan resistor drawing excessive current or causing an open circuitpossible
  • Internal PCM driver faultrare

How to diagnose

  1. Read the stored codes and freeze frame data, note any other cooling or fan related codes, then record and clear only after the fault has been noted
  2. Visually inspect the relay, fuses, wiring and connectors in the power distribution area and near the fan for damage, corrosion, heat marks or water ingress
  3. Check the relevant fuse and the relay supply voltage using the wiring diagram for that model and engine
  4. Swap the relay with a known good identical one, if the layout allows, and see whether the fault changes
  5. Test the relay coil resistance and contact operation on the bench against the specification
  6. Command the fan on with a scan tool bidirectional test, if supported, and listen for the relay clicking and the fan responding
  7. Check the control wire from the PCM to the relay for continuity, short to earth and short to voltage with the PCM connector disconnected
  8. Test the fan motor current draw and the fan wiring for faults before condemning the PCM

How to fix

  • Replace the faulty low speed fan relay
  • Repair or replace damaged wiring and clean or replace corroded connector terminals
  • Replace the blown fuse after finding and correcting the cause of the overload
  • Replace the fan motor or resistor if testing shows it is faulty
  • Replace or repair the PCM only after wiring, relay and fan have been proven good

Can I keep driving?

Medium severity

Short, cautious journeys are possible, but the car may overheat in traffic or at idle, so watch the temperature gauge closely. Fix it soon, and stop immediately if the engine temperature rises towards hot.

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

This code for other makes

Nearby codes