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P1491 and P1489 Trouble Codes on 2001 Dodge Van 3500: Diagnosis for Vehicle with Engine-Driven Radiator Fan

Model: 2001 Dodge Van 3500 Fault Code: P1489 Posted: 2016-08-26 11:00

I'm experiencing two diagnostic trouble codes, P1491 and P1489, on my 2001 Dodge Van 3500. This vehicle does not have an electric radiator fan; instead, the radiator fan is driven by the engine via a fan clutch attached to the water pump. Despite this design, these two codes are stored in the engine control module (ECM). I've noticed occasional drivability issues, such as overheating symptoms or performance drops. Interestingly, when I apply ice to the ECM, the vehicle runs smoothly and the codes disappear temporarily. However, they return after restarting. Given that there is no electric fan system, what could be causing these codes? Is it possible for a mechanical fan setup to trigger these specific fault codes?

Related fault codes
P1489P1491
Comments (3)
Anonymous 2016-08-26 11:47

It's possible you have an 'electronically controlled viscous fan drive' (ECVCF) system. Look for wiring harnesses connected to the fan clutch, as this component may still be electronically monitored by the ECM. Also, could you confirm which engine type you have? A Cummins diesel is a common configuration in full-size vans—this might help narrow down the diagnosis. Additionally, check the underhood fuse box (PDC) for any relays related to the cooling fan system.

Anonymous 2016-08-26 11:53

There are no electronic controls on the radiator fan. I've personally replaced the water pump twice and found no wiring harnesses connected to a fan. This is a gasoline-powered engine—specifically a 360 CID (5.9L) V8. Dodge did not offer diesel engines in full-size vans during this model year. I’ve inspected the underhood fuse box, and none of the fuses are labeled for an engine cooling fan. There is only one fan-related fuse, which powers the A/C blower motor—this works normally.

Anonymous 2016-08-26 13:01

I believe P1491 and P1489 are related to an Electronically Controlled Viscous Fan Drive (ECVCF) system. While I don’t have access to the factory manual right now, this is a common cause of these codes in older Dodge models—even with mechanical fan setups. It's worth trying a different OBD2 scanner to verify the readings, as relying on the 'ice trick' may not provide accurate or consistent results. What specific drivability issues are you experiencing? Are they limited to overheating, stalling, or reduced power? This will help determine whether the issue is related to cooling system performance or ECM misreading.