2002 Jeep Grand Cherokee Logo
Posted on Dec 03, 2017
Answered by a Fixya Expert

Trustworthy Expert Solutions

At Fixya.com, our trusted experts are meticulously vetted and possess extensive experience in their respective fields. Backed by a community of knowledgeable professionals, our platform ensures that the solutions provided are thoroughly researched and validated.

View Our Top Experts

2002 Jeep GCL - Have had engine code P1491 and replaced radiator fan relay. Then had code for throttle pedal postition sensor and replaced that. Fan was not working and had P1491 again. Replaced fan relay and now have stalling at low rpm or idle. Took to have code read and says throttle position sensor again. Help?

2 Answers

Rick M

Level 3:

An expert who has achieved level 3 by getting 1000 points

Superstar:

An expert that got 20 achievements.

All-Star:

An expert that got 10 achievements.

MVP:

An expert that got 5 achievements.

  • Jeep Master 4,148 Answers
  • Posted on Dec 03, 2017
Rick M
Jeep Master
Level 3:

An expert who has achieved level 3 by getting 1000 points

Superstar:

An expert that got 20 achievements.

All-Star:

An expert that got 10 achievements.

MVP:

An expert that got 5 achievements.

Joined: Jun 26, 2017
Answers
4148
Questions
0
Helped
1254327
Points
13941

Did you clean the rust off the frame where the new relay attaches? This is a critical cooling/grounding point for the relay. So is good ground at G108 near the power distribution center. If you just slap on a new relay without cleaning the rust, you'll get this fan problem. But there's no common wiring between the relay and the throttle position sensor. The TPS enters the control module in connector 1 and the radiator relay enters in connector 2,So you've got two separate issues here.

James Hensley

Level 2:

An expert who has achieved level 2 by getting 100 points

MVP:

An expert that got 5 achievements.

Sergeant:

An expert that has over 500 points.

Habit-Forming:

Visited the website for 3 consecutive days.

  • Expert 161 Answers
  • Posted on Dec 03, 2017
James Hensley
Expert
Level 2:

An expert who has achieved level 2 by getting 100 points

MVP:

An expert that got 5 achievements.

Sergeant:

An expert that has over 500 points.

Habit-Forming:

Visited the website for 3 consecutive days.

Joined: Feb 04, 2013
Answers
161
Questions
0
Helped
39079
Points
579

That sounds like a computer problem have you jumped anyone because that can hurt your computer in your vehicle hope this helps Merry Christmas

Ad

5 Related Answers

Anonymous

  • 3 Answers
  • Posted on Jan 01, 2009

SOURCE: PO171 OBD-II Trouble Code " System Lean To Bank 1

Check PCV valve and be sure it is not stuck open.  Check for vacuum leak at intake manifold.  

Ad

Anonymous

  • 837 Answers
  • Posted on Mar 25, 2009

SOURCE: 2001 Jeep Grand Cherokee code P1391

I would check to be sure that the timing chain hasn't jumped at all ..

freetek

Steve Allison

  • 5569 Answers
  • Posted on May 26, 2009

SOURCE: radiator fan not working replaced relay,temp

You didn’t mention replacing the temperature sensor located on the block in the path of the ‘cooled’ coolant.
I can’t tell you any closer where to look for it since you didn’t specify which engine you have.
This device is a solid state item called a thermistor.
With the air temperature around 77 degrees F and a 'cold' engine, it should measure about 10,000 Ohms and hot, around 1,200 Ohms while disconnected from its mating connector.
With the ignition on, and the connector disconnected from the sensor, you should measure about 5 volts coming from the ECU.
If this has failed, the ECU is not getting the right info back from the sensor and doesn’t know if the fan is needed or not.
 

Anonymous

  • 9 Answers
  • Posted on Jun 05, 2009

SOURCE: My 1999 Jeep GCL overheated, my a/c works when on high

Are u talking about engine overheating? ac needs blower motor reistat if engine is over heating see if fan is working above 218 degrees if not replace cooling fan relay its under passenger side head light .

Anonymous

  • 5 Answers
  • Posted on Aug 10, 2009

SOURCE: 2002 jeep grand cherokee fan not working?????

Replace the fan relay switch. The dealer will charge you 400 to pull the bumper off, or you can buy the part for 45 and cut the hole in the plastic near the passenger headlight assembly and replace it yourself. There are instructions for this procedure on the web somewhere. I have had this problem more than once with my 02 GC V6.

Ad

Add Your Answer

×

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

0helpful
1answer

I have a 2003 Jeep Liberty. My check engine light came on and the meter shows a P1491. What is this?

Radiator Fan Control Relay Circuit
An open or shorted condition detected in the radiator fan control relay control circuit. This includes PWM solid state relays
0helpful
1answer

P0300, P0305, P0306, P0320, P1491

Yes, most probably a new crank position sensor will solve your stalling problem. I would change that sensor first and then see if you still get other fault codes. The fan continuously running will reduce the lifetime of the fan and will lower the mpg. I would change the relay.
0helpful
1answer

P0300, P0305, P0306, P0320, P1491

Not necessarily, you will just have to unplug it. The fan relay switch isn't that expensive so you should if you can. The multiple misfires usually means that you need a tune-up with plugs,coils and some sensors when required.
0helpful
2answers
0helpful
1answer

Will a leak cause the radiator fan relay curcuit to malfunction on a 2003 jeep liberty 3.7

a leak in coolant system will cause air pocket in the coolant system around the engine coolant temperature sensor.coolant sensor is a thermistor in which when hot cool cause it resistance decrease which affect the voltage from sensor to pcm which will cause engine coolant to turn on.if coolant level okay,check coolant fan fuse and relay, if all is good,engine coolant temperature sensor could be bad or have vechicle code scan for pcm problems it control the coolant fan.fill coolant system to correct level make sure engine coolat reservoir is at full cold mark and not empty.fill coolant system check for leaks,refill coolant overflow jug back to full cold mark dont over fill, if coolant overflow stay empty you have leak either its leaking or you have radiator hoses or radiator leaking coolant.when coolant overflow jug run dry it cause air get in coolant system causing overheating problems.
0helpful
1answer

My 2002 jeep grand cherokee laredo wull not start shutdown 2 days ago checked all fuses but the ecu fuses don't know how to find them

According with your other quesions, the DTC P1491 code is actually radiator fan control relay circuit.
Soft reset if the battery disconnect would have erased the code; the first thing I would replace for that code (fan relay).
Additionally, its possible thta your THEFT system is activated, check owners manual to disarm. Check details here:
- Grand Cherokee fuses

- Diagnostic Trouble Codes

Hope this helps.
0helpful
1answer

1999 Jeep Cherokee Sport wont shift into overdrive P1491

P1491 - Radiator Fan Control Relay Circuit Open Or Shorted

When monitored: with the ignition key on, battery voltage greater than 10.0 volts and
the pcm requests the radiator fan to be turned on.
Set condition: an open or shorted circuit is detected in the radiator fan relay control
circuit.

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

Check ot and keep us updared.
4helpful
2answers

I was in a minor fender bender ( bumped the car in front of me and did little cosmotic damage.) After that my check engine light came on. The code is P1491 Manufacturer Control Axillary Emissions...

The DTC (Data Trouble Code) P1491 for Chrysler-Jeep is for the Radiator Fan Control Relay Circuit, and the radiator fan control relay is located between the radiator and the AC condenser, and there is the possibility that a collision could have damaged the radiator control relay or the wiring. Here is an image of a chrysler radiator control relay to help assist you.




zaraki_31.jpg
2helpful
2answers

P1491 diagnostics code for 2003 Jeep Grand Cherokee


Trouble Code: P1491 You PCM does not sense current to radiator fan when it turns it on. Is the fan coming on or not? Usually not when you have this code. Problem can be with the fuse, relay, wiring or fan itself. First check the fuse. If good, next try swapping the relay with another one in the engine compartment relay box, such as the horn relay.
Let the car warm up and see if the fan will come on. If yes, get a new relay. If not, either use a test light to see if there is voltage at the fan connector when the engine is on and hot, or else test the fan motor by hotwiring it to the battery. If none of this works, please get back to me for how to troubleshoot the wiring.


Radiator Fan Control Relay Circuit Malfunction
Possible Causes:


Radiator fan control relay circuit is open or shorted to ground Radiator fan control relay circuit is open (test power to IGN) Radiator fan control relay is damaged or has failed PCM has failed

Not finding what you are looking for?

1,384 views

Ask a Question

Usually answered in minutes!

Top Jeep Experts

ZJ Limited
ZJ Limited

Level 3 Expert

17989 Answers

Thomas Perkins
Thomas Perkins

Level 3 Expert

15088 Answers

john h

Level 3 Expert

29494 Answers

Are you a Jeep Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...