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Anti theft system preventing car from starting
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MENTELROAD
Novice
Feb 12, 2010, 12:10 PM
Post #1 of 8
(11171 views)
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Anti theft system preventing car from starting
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'97 Ford Expedition. At times the anti-theft system will not let the car start. The theft light will blink for about 20 or 30 seconds, shut off then the car will start. Other times it will blink for 30 seconds go off and not let the car start. At other times it will not blink and go off in about 3 seconds and the car starts. There is not pattern as to when this will happen. Where do I start?
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Feb 12, 2010, 9:11 PM
Post #2 of 8
(11156 views)
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Re: Anti theft system preventing car from starting
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Freaking alarms + anti-theft devices are like a revenge against humanity. Hate them. Will need to know and still be at a loss whether this is factory installed or aftermarket junk which frequently gets hacked into wiring which causes issues and devices are cheap junk and go bad too.
I know some folks may need this stuff - a sad thing that keys alone aren't enough. If worried I suggest non invasive wheel and brake locking things like "The Club" idea and have seen those defeated in seconds by pro thieves.
Let's begin with whether this is an OE system or aftermarket,
T
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MENTELROAD
Novice
Feb 13, 2010, 6:56 AM
Post #4 of 8
(11147 views)
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Re: Anti theft system preventing car from starting
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Hi Tom--This is original equipment alarm. Would love to bypass the whole thing if we could but the manuals say it is tied into too many other things in the dash.
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Hammer Time
Ultimate Carjunky
/ Moderator
Feb 13, 2010, 7:13 AM
Post #5 of 8
(11143 views)
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Re: Anti theft system preventing car from starting
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Description and Operation Notes
The Passive Anti-theft System (PATS) uses radio frequency identification technology to deter a driveaway theft. Passive means that it does not require any activity from the user.
- During each vehicle start sequence, the ignition key identification code is requested by the PATS module.
- If the key's ID code has been programmed into the system, the vehicle Powertrain Control Module (PCM) is allowed to operate, and enables the vehicle to start.
- If the key's ID code is not programmed into the PATS module, or if no encoded key is detected, then the vehicle PCM is disabled.
The PATS module communicates the state of the security system to the PCM via the module communications network. The PCM, based on the communications from the PATS module, will determine if the vehicle's engine will be enabled to start.
The passive anti-theft system components function as follows:
- THEFT Indicator
- The anti-theft vehicle protection system utilizes the THEFT indicator, located in the instrument cluster, when the ignition switch is turned to the RUN/START position. The indicator provides system prove out and operating status to the customer or technician.
- The passive anti-theft system will activate the indicator signal under the following conditions when the ignition switch is turned to the RUN/START position:
- THEFT Indicator ON two seconds , then OFF.
- Key Code Received/Vehicle Enabled (Programmed key).
- THEFT Indicator ON two seconds , then OFF one second , then ON continuously.
- Key Code Received/Vehicle Disabled (Assembly plant use only; less than two keys programmed).
- THEFT Indicator ON two seconds , then flash for one minute , then flash diagnostic trouble code 16 ten times .
- Key Code Received/Vehicle Enabled or Disabled (No PCM Verification).
- If vehicle starts, PCM is not working with control module.
- If vehicle does not start, REFER to Information Bus.
- THEFT Indicator flashes for one minute .
- No Key Code Received (Key damaged, Non-encoded key, Wiring or Transceiver concern).
- THEFT Indicator flashes for 15 minutes .
- Key Code Received/Vehicle Disabled (Key not programmed).
- Encoded Ignition Key
- When the vehicle ignition switch is placed into either RUN or START, the PATS module requests the ignition key ID code. The PATS module requests the ignition key ID code by supplying power, ground, and the carrier signal to the transceiver to energize the ignition key. After the energize period, the key transmits its ID code to the transceiver module. This ignition key is much larger in size due to the electronics that are located in the head of the ignition key.
- Transceiver
- The transceiver module is used to interface the PATS module to the encoded ignition key. The transceiver sends power to the encoded key and receives the ignition key data signal and sends it to the PATS module.
- Passive Anti-Theft System Module
- The PATS module contains circuitry to connect the vehicle electrical system, the transceiver module, the vehicle module communications network, and the vehicle theft indicator located in the instrument cluster. The PATS module uses a microprocessor to control the system functions. The PATS module microprocessor stores the ignition key codes in non-volatile memory. The PATS module can be diagnosed through the data link connector.
- Powertrain Control Module (PCM)
- The passive vehicle protection system utilizes the engine management capabilities of the PCM to enable or disable the vehicle engine. The module communications are used to send and receive messages to and from the PCM.
- Within one second after engine start, the PCM must receive an enable signal or the engine is disabled before the vehicle can be moved.
If the PATS module recognizes a stored ignition key code but there is a module communication network concern preventing the PCM from recognizing the start enable signal from the PATS module, the vehicle engine will be disabled.
Vehicle Disabling
The passive vehicle protection system will be activated and will disable the vehicle from starting if any of the following actions occur:
- Damaged encoded key.
- Unprogrammed key.
- Non-encoded key (key has no electronics).
- Wiring concern.
- Control module concern.
- Module Communications Network concern.
Vehicle Enabling
For normal anti-theft system prove out and vehicle enabling to occur, the THEFT indicator must prove out as follows:
- Normal operating prove out on the THEFT indicator is two seconds ON then OFF after the ignition switch has been exercised from OFF to RUN/START position.
- If normal two second prove-out occurs and the engine cranks for more than one second after the ignition switch is turned to the START position but fails to start, the fault is not with the passive anti-theft system pre-check.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Feb 13, 2010, 9:31 AM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Feb 13, 2010, 7:32 AM
Post #6 of 8
(11140 views)
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Re: Anti theft system preventing car from starting
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These things are a pest for the owner IMO especially as vehicles age. What was the original procedure to arm and disarm this system? Was it all thru key-chain remote? If so try a new battery if you haven't done one in a good while.
I don't know of one way to disarm all systems and if I did (there isn't one) and posted it, it would defeat the intended purpose of the damn things.
You may need a dealer for help with this. Many will go nuts with any battery disconnect or failure if "memory" savers aren't used. Original papers with the car when new should have had info on it probably now lost,
T
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MENTELROAD
Novice
Feb 13, 2010, 2:41 PM
Post #7 of 8
(11131 views)
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Re: Anti theft system preventing car from starting
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Well Thanks everybody. Looks like this will need some extra help from the experts. Probably won't mess with it ourselves.
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nickwarner
Veteran
/ Moderator
Feb 13, 2010, 6:37 PM
Post #8 of 8
(11126 views)
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Re: Anti theft system preventing car from starting
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I can't stand those alarms. I got one for all my cars. Its made by Mossberg, needs no installation, and have yet to see even the best crook find a way around it. Such a shame that we even need so much as door locks in this world.
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