2002 T&C ltd has p1491 code, but both fans are still running. What else can I check to clear the code?

SOURCE: Check Engine LIght Problem code P1491

Don't rush to replace the fan itself until you have tested it. Check the fan relay and relay fuse inside the vehicle. Hopefully it will be just a failed relay and replacement ($12 at dealer) or/and an inexpensive 10amp or 30amp fuse. There can be multiple issues causing this code.

In my case, the fan relay failed (burnt). 2000 Dodge Durango. The PCM was also damaged and requires replacement, awaiting delivery. A remanufactured PCM can be purchased online for substantial less than at the dealer. We tested the fan by supplying power directly to the fan and it runs fine. We had to remove a cover (easy to remove) under the vehicle near the fan to gain access to the connector Use a fused link for testitng to prevent damage during the test. Using a multimeter, I found power 12.5volts from the 30amp fuse circuit which supplies the power for the fan, 12.5 volts from the PCM circuit with the key on, but only 5.16volts from the 10amp fuse circuit with the key on. A continuity test showed the 10amp fuse inside the fuse box inside the vehicle was good. The 30amp fuse in the power distribution box was good when tested for continuity. Checked resistance on all curcuits and they were well within limits. I also checked the wiring to the fan for continuity and resistance. After my tests were completed, a Dodge technican concluded the PCM is bad and is not grounding the circuit as it should. If you want to troubleshoot this yourself, see if your local library has access to ALLDATA which will have diagnostic information and the diagrams of the circuit involved. A Haynes manual for the vehicle, I purchased one at Autozone, can be helpful also.

Mike Watson

• 474 Answers
• Posted on Feb 03, 2010

SOURCE: engine code p1491 for Dodge Caravan 3.3

radiator fan relay circuit.

SOURCE: 2002 Dodge caravan 3.3L. Code P1491. Replaced with

you have an open or shorted condition detected in the low speed radiator fan relay control circuit. hope this will help!!!!

ZJ Limited

• 17989 Answers
• Posted on Dec 20, 2011

SOURCE: Where is the relay located for the code P1491? On a 2000 jeep grand Cherokee?

Hi there:
DTC P1491 - RAD FAN CONTROL RELAY CIRCUIT

DTC P1491 is for the cooling fan relay control circuit as you've found already. Start by checking the fuse for the fan relay. Its in the box under the hood, a 40 amp fuse.

If you've got a couple jumper wires, you can unplug the fan connector and carefully jump the fan to see if it works. The fan connector is on the right side of the back of the fan shroud. Unplug it and jump the black wire to ground and the green to positive. You've got to be very careful doing this though-you are in very tight quarters, its not hard for your jumper wires to touch each other in the connector and short together, and if you use small diameter jumper wires they will get hot quickly when the fan comes on.

If the fan doesn't come on when you jump it, or if it runs slow or sounds bad, you've got a bad motor and will need to replace the fan assembly. One thing that does happen somewhat often, is a bad fan motor will burn up the relay. If the fan motor is drawing too much current it will overload the relay and burn it up. This is why its so important that if the fan motor runs slow or makes noise that you replace it, or you may end up burning up relays frequently.

If the fan runs and the fuse is good, its very likely you just need a fan relay. This is a pulse width modulated relay, not the on/off clicker type you'd find in the fuse box. This unit is capable of infinite speed control. It gets very hot in operation, so its mounted to the body sheet metal to allow heat to dissipate through the sheet metal. The relay is mounted under the right headlamp held down with two 8mm screws. To get to it you have to remove the front bumper cover and headlamp bracketry to access the relay. These relays are pretty common.

Check and test this possible causes:
radiator fan ctrl rly circuit wire harn intermittent defect
radiator fan ctrl rly circuit wire harn observable defect
radiator fan relay ground circuit open
rad fan relay control circuit open
radiator fan relay control circuit short to ground
rad fan control relay defective
PCM defective

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

ZJ Limited

• 17989 Answers
• Posted on Mar 26, 2012

SOURCE: 2002 jeep liberty p1491

Hi there:

P1491 is for the cooling fan relay control circuit as you've found already.Start by checking the fuse for the fan relay. Its in the box under the hood, a 40 amp fuse.If you've got a couple jumper wires, you can unplug the fan connector and carefully jump the fan to see if it works. The fan connector is on the right side of the back of the fan shroud. Unplug it and jump the black wire to ground and the green to positive. You've got to be very careful doing this though-you are in very tight quarters, its not hard for your jumper wires to touch each other in the connector and short together, and if you use small diameter jumper wires they will get hot quickly when the fan comes on.If the fan doesn't come on when you jump it, or if it runs slow or sounds bad, you've got a bad motor and will need to replace the fan assembly. One thing that does happen somewhat often, is a bad fan motor will burn up the relay. If the fan motor is drawing too much current it will overload the relay and burn it up. This is why its so important that if the fan motor runs slow or makes noise that you replace it, or you may end up burning up relays frequently.If the fan runs and the fuse is good, its very likely you just need a fan relay. This is a pulse width modulated relay, not the on/off clicker type you'd find in the fuse box. This unit is capable of infinite speed control. It gets very hot in operation, so its mounted to the body sheet metal to allow heat to dissipate through the sheet metal. The relay is mounted under the right headlamp held down with two 8mm screws. To get to it you have to remove the front bumper cover and headlamp bracketry to access the relay. These relays are pretty common.

Hope helps.