Pinpoint Test F: The Anti-Theft Indicator Is Always/Never On

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Passive Anti-Theft System for schematic and connector information.

Normal Operation 

The passive anti-theft system (PATS) uses a visual anti-theft indicator located in the light sensor. This indicator proves out for 3 seconds when the key is turned to the ON or START position. The central junction box (CJB) fuse 4 (10A) provides voltage on circuit 905 (VT/LB) to the light sensor/theft indicator and circuit 1269 (OG/RD) is the ground circuit that is grounded by the PCM. If there is a PATS concern, this indicator either flashes rapidly or glows steadily (for more than 3 seconds) when the key is turned to the ON or the START position. PATS also flashes the anti-theft indicator every 2 seconds at key off to act as a visual theft deterrent.

This pinpoint test is intended to diagnose the following:

• Fuse
• Anti-theft indicator
• Wiring, terminals or connectors
• PCM

PINPOINT TEST F: THE ANTI-THEFT INDICATOR IS ALWAYS/NEVER ON 

1. F1 CHECK THE ANTI-THEFT INDICATOR FOR CORRECT OPERATION 
   • Key in OFF position.
   • Disconnect: PCM C175t
   Fig 1: Connecting Fused Jumper Wire
   Courtesy of FORD MOTOR CO.
   • Connect, then disconnect a fused (10A) jumper wire between the PCM C175t-33, circuit 1269 (OG/RD), harness side and ground.
   • Does the anti-theft indicator illuminate, then turn off? 
   1. YES  : Go to  F5.
   2. NO  : Go to  F2.
2. F2 CHECK THE VOLTAGE TO THE ANTI-THEFT INDICATOR 
   • Disconnect: Light Sensor C287
   Fig 2: Checking Circuit For Voltage
   Courtesy of FORD MOTOR CO.
   • Measure the voltage between the light sensor C287-3, circuit 905 (VT/LB), harness side and ground.
   • Is the voltage greater than 10 volts? 
   1. YES  : Go to  F3.
   2. NO  : VERIFY the central junction box (CJB) fuse 4 (10A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation.
3. F3 CHECK CIRCUIT 1269 (OG/RD) FOR A SHORT TO GROUND 
   Fig 3: Checking Circuit For Short To Ground
   Courtesy of FORD MOTOR CO.
   • Measure the resistance between the light sensor C287-4, circuit 1269 (OG/RD), harness side and ground.
   • Is the resistance greater than 10,000 ohms? 
   1. YES  : Go to  F4.
   2. NO  : REPAIR the circuit. TEST the system for normal operation.
4. F4 CHECK CIRCUIT 1269 (OG/RD) FOR AN OPEN 
   Fig 4: Checking Circuit For Open
   Courtesy of FORD MOTOR CO.
   • Measure the resistance between the light sensor C287-4, circuit 1269 (OG/RD), harness side, and the PCM C175t-33, circuit 1269 (OG/RD), harness side.
   • Is the resistance less than 5 ohms? 
   1. YES  : INSTALL a new light sensor. REFER to EXTERIOR LIGHTING article. TEST the system for normal operation.
   2. NO  : REPAIR the circuit. TEST the system for normal operation.
5. F5 CHECK FOR CORRECT PCM OPERATION 
   NOTE: When a new PCM is installed, the PATS keys must be programmed into the PCM.
   • Disconnect the PCM connector.
   • Check for:
     • corrosion
     • damaged pins
     • pushed-out pins
   • Connect the PCM connector and make sure it seats correctly.
   • Operate the system and verify the concern is still present.
   • Is the concern still present? 
   1. YES  : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS article. PROGRAM the PATS keys into the PCM. REFER to Key Programming Using Diagnostic Equipment . TEST the system for normal operation.
   2. NO  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST the system for normal operation.