VATS Q&A

**GMCSonoma** · 05-18-2005, 04:34 PM

A colleague of mine sent me this, this may answer any future troubleshooter issues anyone may have with the VATS anti-theft system on the GM's.
What Is VATS And How Does It Work?
VATS stands for Vehicle Anti Theft System. It works by sensing resistance in the 'chip' in your key. The 'chip' is really a resistor pellot. The VATS module controls the starter enable relay and the fuel disable parameter in the ECM. If the wrong resistance is detected, then the VATS module will NOT let the ECM power the fuel pump. It also will NOT let the starter turn.

What Are The Resistance Values?
Your resistor value will be one of these 15:

1 - 402 Ohms
2 - 523 Ohms
3 - 681 Ohms
4 - 887 Ohms
5 - 1.13K Ohms
6 - 1.47K Ohms
7 - 1.87K Ohms
8 - 2.37K Ohms
9 - 3.01K Ohms
10 - 3.74K Ohms
11 - 4.75K Ohms
12 - 6.04K Ohms
13 - 7.50K Ohms
14 - 9.31K Ohms
15 - 11.8K Ohms

The only way to tell which one is yours is to check it with a meter.

What wires come out of the VATS module?
Orange - 12 Volts 10 Amps - Coming from the VATS fuse on the fuse block.
Black/White - Ground
Black/Yellow - Starter Enable Relay Control - Relay is located behind LH kick panel. Provides ground to relay.
Gray - Security Light - Provides ground to secuity light in instrument panel.
Pink/Black - 12 Volts 10 Amps - Coming from the ECM fuse on the fuse block.
Dark Blue - ECM Fuel Enable Control - Ground going to the ECM.
Purple/White - Resistor Pellot - Ground going to the lock cylinder.
White/Black - Resistor Pellot - X Ohms ground resistance going to the module coming from the lock cylinder.

**nailhead425** · 05-19-2005, 01:02 AM

One for the files! Thank you Sir.

Water Boy · 05-18-2008, 02:17 PM

Quote<<
Purple/White - Resistor Pellot - Ground going to the lock cylinder.
White/Black - Resistor Pellot - X Ohms ground resistance going to the module coming from the lock cylinder
Quote>>

It would seem, for troubleshooting purpose, that placing a proper sized resistor between these 2 wires, and the vehicle would start correctly, would indicate there was a "problem" in the switch module and/or wiring in the column.

I've had random "no start" issues in the past. Even a tow to the dealer was full of ???? after they did their diagnostics.

I'm just thinking' out loud.

05-18-2005, 04:34 PM	#1 (permalink)
GMCSonoma GMI Fixed Ops Contributor Join Date: Sep 2004 Posts: 8,942	VATS Q&A A colleague of mine sent me this, this may answer any future troubleshooter issues anyone may have with the VATS anti-theft system on the GM's. What Is VATS And How Does It Work? VATS stands for Vehicle Anti Theft System. It works by sensing resistance in the 'chip' in your key. The 'chip' is really a resistor pellot. The VATS module controls the starter enable relay and the fuel disable parameter in the ECM. If the wrong resistance is detected, then the VATS module will NOT let the ECM power the fuel pump. It also will NOT let the starter turn. What Are The Resistance Values? Your resistor value will be one of these 15: 1 - 402 Ohms 2 - 523 Ohms 3 - 681 Ohms 4 - 887 Ohms 5 - 1.13K Ohms 6 - 1.47K Ohms 7 - 1.87K Ohms 8 - 2.37K Ohms 9 - 3.01K Ohms 10 - 3.74K Ohms 11 - 4.75K Ohms 12 - 6.04K Ohms 13 - 7.50K Ohms 14 - 9.31K Ohms 15 - 11.8K Ohms The only way to tell which one is yours is to check it with a meter. What wires come out of the VATS module? Orange - 12 Volts 10 Amps - Coming from the VATS fuse on the fuse block. Black/White - Ground Black/Yellow - Starter Enable Relay Control - Relay is located behind LH kick panel. Provides ground to relay. Gray - Security Light - Provides ground to secuity light in instrument panel. Pink/Black - 12 Volts 10 Amps - Coming from the ECM fuse on the fuse block. Dark Blue - ECM Fuel Enable Control - Ground going to the ECM. Purple/White - Resistor Pellot - Ground going to the lock cylinder. White/Black - Resistor Pellot - X Ohms ground resistance going to the module coming from the lock cylinder. __________________ certified GM Dealer Parts Manager since 1994 GM Dealer Parts employee since 1987 AMC-Jeep-Renault Dealer Parts employee 1987-90 holder of many GM accredations, too numerous to list and not giving a damn!

05-19-2005, 01:02 AM	#2 (permalink)
nailhead425 GMI Staff Member Join Date: Jan 2005 Location: 85541 Drives: '01 Dodge, '88 3/4T Sub, 3-Nailhead Buicks, Monte Posts: 2,363	Re: VATS Q&A One for the files! Thank you Sir. __________________ "A foolish consistency is the hobgoblin of little minds."-Ralph Waldo Emerson

05-18-2008, 02:17 PM	#3 (permalink)
Water Boy 1.8 Liter ECOTEC Join Date: Dec 2007 Location: Canton (NW of Atlanta) GA Drives: '03 Savana 2500LD 5.3 cargo Posts: 50	Re: VATS Q&A Quote<< Purple/White - Resistor Pellot - Ground going to the lock cylinder. White/Black - Resistor Pellot - X Ohms ground resistance going to the module coming from the lock cylinder Quote>> It would seem, for troubleshooting purpose, that placing a proper sized resistor between these 2 wires, and the vehicle would start correctly, would indicate there was a "problem" in the switch module and/or wiring in the column. I've had random "no start" issues in the past. Even a tow to the dealer was full of ???? after they did their diagnostics. I'm just thinking' out loud.

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