The dreaded "wrench" light

[Dustmonster]

Had this light come on last winter along with the Check Engine light. Owners manual says the truck is in "Limp Home" mode. When I fixed the fuel issue causing the check engine light in the spring, the wrench went away as well. Problem solved.......NOT!
The wrench came back a couple of days ago and really has me stumped.
1. Almost every morning in the cold approx. 4 miles from the house.
2. Stays on all the way to work (22 miles).
3. Comes on immediatly upon startup if I stop for gas or coffee.
4. Is off all the way home in the warm afternoon as well as all evening no matter how much I drive.
5. Performance not affected when light is on.
I can only assume that having a bright orange wrench light up in your dash panel can't be a good thing.
Thought that maybe it came on in the cold because my blend door actuator is not working and sometimes I run the defroster in cold to clear the windshield, but this morning it came on without defrost.
Could this be a sensor gone bad that monitors the inbound air temp to the throttle body (if there is such a thing)?

 

[swetrid]

Do you have any codes? If not here is a tsb from Ford.
Printable View (7 KB)
TSB
05-6-1 WRENCH LAMP ON AND NO DTC STORED

Publication Date: March 9, 2005

FORD: 2004-2005 Explorer
MERCURY: 2004-2005 Mountaineer


ISSUE:
Some 2004-2005 Explorer 4dr/Mountaineer vehicles may exhibit a wrench lamp on with no accompanying diagnostic trouble codes (DTCs).

ACTION:
Reprogram the powertrain control module (PCM) to the latest calibration using WDS release B36.3 or higher. Calibration files may also be obtained at www.motorcraft.com. Also, perform an accelerator pedal position sensor sweep test to verify sensor operation. Refer to the following Service Procedure.

SERVICE PROCEDURE

After reprogramming the PCM perform the following:

Turn the ignition key to the KOEO (key on, engine off) position.
Perform a slow (approximately 2 second) sweep of the accelerator pedal: from foot off the pedal; to a fully depressed pedal; and back to the foot off the pedal position, while monitoring the wrench lamp.
If the wrench lamp turns on, or a DTC for the accelerator pedal position is set, proceed to the appropriate PC/ED pinpoint test for the DTC and follow normal diagnostics.
If no wrench lamp or DTC, return the vehicle to the customer.

WARRANTY STATUS:
Eligible Under Provisions Of New Vehicle Limited Warranty Coverage

OPERATION DESCRIPTION TIME
050601A 2004-2005 Explorer/Mountaineer - Reprogram The Powertrain Control Module (PCM) And Perform An Accelerator Pedal Position Sensor Sweep Test (Do Not Use With 12650D, 12650D84) 0.6 Hr.

DEALER CODING
BASIC PART NO. CONDITION CODE
RECAL 04

--------------------------------------------------------------------------------

NOTE: The information in Technical Service Bulletins is intended for use by trained, professional technicians with the knowledge, tools, and equipment to do the job properly and safely. It informs these technicians of conditions that may occur on some vehicles, or provides information that could assist in proper vehicle service. The procedures should not be performed by "do-it-yourselfers". Do not assume that a condition described affects your car or truck. Contact a Ford, Lincoln, or Mercury dealership to determine whether the Bulletin applies to your vehicle. Warranty Policy and Extended Service Plan documentation determine Warranty and/or Extended Service Plan coverage unless stated otherwise in the TSB article. The information in this Technical Service Bulletin (TSB) was current at the time of printing. Ford Motor Company reserves the right to supercede this information with updates. The most recent information is available through Ford Motor Company's on-line technical resources.

Copyright © 2005 Ford Motor Company