Ford Repair Questions? Ask a Mechanic for Answers ASAP
Ok, I will have to look tomorrow it is too dark to see what I am doing. I will have to pull out the PCM from inside so I can see the connector number. I dont have a system to check for codes. I will see if harbor freight tools as such a tool.
It would be nice to have the pin out since I have spent the good part of the of the day looking for schematics. It seems like the schematics are treated like classified material and is very hard to find.
do I need to build any devices for a draw test or can i just put my meter inline to measure the draw. I have to build a simple device to measure draw when I trouble shoot Generators during a draw test. Just wandering if I need one here for the Ford?
Thats for resonding
inside the cabin I pulled the fuses.
I noteded that fuse#1 (Radio) dimmed the test light. Not a lot though. That position is the keep the clock alive in the radio. I assume that is normal drain.
I got to fuse 15 - pulled it and the test light went out. I replaced the other fuses and left 15 out. I quickly found out what the GEM was for due to the fact I could not take vehicle out of park. <smile>
Im trying to locate the PATS so I can unplug that and retest to see if the test light is remaining on. And the same with the GEM. I found the GEM location I just cant find the PATS location I wanted to know which one is causing the draw.
However, After reviewing many newsgroups on the GEM with excursions and water leaking down on to it I probably will assume it will be the GEM.
I also read that the alternator or regulator being faulty will cause my symptoms and make it look like the GEM or PATS is faulty.
My question is this: Can I test the GEM or is that only scanned at factory service center? If I can test it that would be great and Pin outs and or schematic would be nice.
The same question goes for the PATS as well.
But based on the symptoms the door locks locking and unlocking on its own with fuse 15 in; I assume it will be GEM since it controls the door locks. Also the overdrive and speedometer needle fluctating points to GEM.
A schematic with both wiring to PATS and GEM will tell me what is common that makes the PATS act up as well. Before buying parts I want to be absolutely sure. since the parts are not cheap.
And thanks for your time.
Principles of Operation
The following is list of GEM controlled functions:
The generic electronic module (GEM) constantly monitors its subsystems for concerns. If a concern is found in one of the subsystems, the GEM will record the concern in the form of a diagnostic trouble code (DTC). The ignition switch position is very important to the GEM function. Often times, erratic or unexpected GEM function can be traced to concerns with ignition switch inputs.
Ignition Switch Positions
The position of the ignition switch is very important to correct GEM operation. The following is a brief description of five ignition switch positions.
When the ignition switch is in the RUN position, battery voltage should be present at the GEM RUN and RUN/ACC input terminals.
When the ignition switch is in the ACC position, battery voltage should be present at the GEM RUN/ACC input terminal only.
When the ignition switch is in the START position, battery voltage should be present at the GEM start/clutch depressed input.
The GEM module does not have an OFF or LOCK switch state input. The GEM will assume the OFF or LOCK position when there are no RUN, ACC, or START signals present.
Inspection and Verification
Visual Inspection Chart
Refer to Wiring Diagrams Cell 112 ( F-SUPER DUTY 250-550/EXCURSION, F-53 Motorhome Chassis ), Passive Anti-Theft System (PATS) for schematic and connector information.
The passive anti-theft system (PATS) uses radio frequency identification technology to deter a drive away theft. Passive means that it does not require any activity from the user. This system is known as SecuriLock® in North America, Safeguard® in the U.K., and PATS in continental Europe. This information can be found in owner literature.
The PATS uses a specially-encoded ignition key. Each encoded ignition key contains a permanently installed electronic device called a transponder. Each transponder contains a unique encrypted identification code out of over 18 billion, billion combinations.
Each encoded ignition key must be programmed into a vehicle's PATS module before it can be used to start the engine. There are special diagnostic repair procedures in this section that must be carried out if the encoded ignition keys need to be replaced.
The transceiver module communicates with the encoded ignition key. This module is located behind the steering column shroud, and contains an antenna connected to a small electronics module. During each vehicle start sequence, the transceiver module reads the encoded ignition key identification code and sends the data to the PATS module.
The control functions are contained in the PATS module. This module carries out all of the PATS functions such as receiving the identification code from the encoded ignition key and controlling engine enable. The PATS module initiates the key interrogation sequence when the vehicle ignition switch is turned to RUN or START.
PATS uses the powertrain control module (PCM) to enable or disable the engine. The PATS module communicates with the PCM over the standard corporate protocol (SCP) communication network in order to enable engine operation. The PATS module and the PCM use sophisticated messages in order to prevent theft. The PATS and PCM share security data when first installed together, making them a matched pair. After this security data sharing, these modules will not function in other vehicles. The PCM shared security ID is remembered even if the battery is disconnected. The PATS module also stores the vehicle's key identification code, even if the battery is disconnected. There are special diagnostic repair procedures outlined in this workshop manual that may be carried out if either the PATS module or the PCM needs replacement.
All elements of the PATS must be functional before the engine is allowed to start. If any of the components are not working correctly, the vehicle will not start.
PATS uses a THEFT indicator. This indicator will prove out for three seconds when the ignition switch is turned to RUN or START under normal operation. If there is a PATS concern, this indicator will either flash rapidly or glow steadily when the ignition is turned to RUN or START. PATS also flashes the theft indicator every two seconds at ignition OFF to act as a visual theft deterrent.
The PATS is not compatible with aftermarket remote starting systems, which allow the vehicle to be started from outside the vehicle. These systems may reduce the vehicle security level, and also may cause no-start issues. Remote start systems must be removed before investigation of PATS-related no start issues.
The passive vehicle protection system will be activated and will disable the vehicle from starting if there is a:
NOTE: The Passive Anti-Theft System (PATS) module must be reconfigured after replacement. Refer to Section 418-01.