Passive Anti-Theft System (PATS)
The Passive Anti-Theft System (PATS) is a feature to prevent the vehicle from being driven away by an unauthorized person. The PATS system consists of electronically coded keys, a transceiver device and a control module. When the ignition is switched to position II, the transceiver energizes the ignition key to read it's electronic code that is transmitted back. If the code read equals a code stored in the control module, the Engine Control Module (ECM) will let the engine start. Otherwise, starting of the engine is disabled (through the starter disable relay and the ECM).
A PATS indicator LED provides the driver with the status of the PATS system. The light will flash when the ignition is switched OFF. The PATS light will illuminate when the key is inserted into the ignition lock and will stay illuminated until the system has carried out it's test on the key. If there is a fault with the PATS system the LED will flash a error code. For additional information and diagnostic procedures, see DOOR LOCKS & ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT.
Engine Does Not Crank
See ENGINE DOES NOT CRANK under SYSTEM TESTS
Engine Cranks Slowly
See ENGINE CRANKS SLOWLY under SYSTEM TESTS
Starter Spins; Engine Does Not Crank
Possible Causes
- Starter motor.
Possible Corrections
- Inspect flywheel ring gear for damage.
- Check starter motor for correct installation. If necessary, install a NEW starter motor. See «STARTER»(ref-167192-S36390559142004100800000) under REMOVAL & INSTALLATION.
SYSTEM TESTS
| CAUTION | To prevent damaging wiring harness connector terminals, use adaptor kit, part number 3548-1358-00 when probing connectors to take measurements. |
Note. When performing electrical voltage or resistance tests, always use a Digital Volt-Ohmmeter (DVOM) accurate to 3 decimal places, and with an up-to-date calibration certificate. When testing resistance, always take the resistance of the DVOM leads into account.
Note. For battery disconnect procedure, see BATTERY DISCONNECT PROCEDURE under MISCELLANEOUS. For battery reconnect procedure, see BATTERY RECONNECT PROCEDURE under MISCELLANEOUS.
Note. For circuit and connector identification, see WIRING DIAGRAMS and/or CONNECTOR IDENTIFICATION .
Possible Causes
- Battery.
- Starter motor.
- Starter relay.
- Ignition switch.
- Transmission range sensor.
Note. For battery disconnect procedure, see BATTERY DISCONNECT PROCEDURE under MISCELLANEOUS. For battery reconnect procedure, see BATTERY RECONNECT PROCEDURE under MISCELLANEOUS.
Note. For circuit and connector identification, see WIRING DIAGRAMS and/or CONNECTOR IDENTIFICATION .
- Battery.
- Related stater motor circuitry.
- Starter motor.
BATTERY DISCONNECT PROCEDURE
| WARNING | Radio code saving devices must not be used when conducting work on air bag or fuel systems. It must be noted that, when using these devices, the vehicle electrical system is still live although with a reduced current flow. |
| CAUTION | Always stop the engine before disconnecting the battery negative lead and make sure the battery positive lead is isolated. |
Note. Before disconnecting the battery make sure that the radio receiver/cassette player/mini disc player and compact disc player key codes are known and that no data is required from the ECM because battery disconnection will erase any fault codes and idle/drive values held in the Keep Alive Memory (KAM). It is not necessary to disconnect or remove electronic control modules. Radio Code Savers may be used. With the battery disconnected, a Radio Code Saver will allow sufficient current to pass to maintain the radio receiver/cassette player/mini disc player and compact disc player memory, operate the clock and supply the door operated interior lights while isolating the battery in the event of a short circuit.
Always disconnect the battery before commencing repair operations which require the vehicle to be jacked up, work on the engine, work underneath the vehicle or arc welding. Always disconnect battery negative cable first.
BATTERY RECONNECT PROCEDURE
| WARNING | If the battery has been on bench charge, the cells may be giving off explosive hydrogen gas. Avoid creating sparks and if in doubt, cover the vent plugs or covers with a damp cloth. |
| CAUTION | Always make sure that all electrical systems are switched OFF before reconnecting the battery to avoid causing sparks or damage to sensitive electrical equipment. |
Note. Whether one or both cables were disconnected, a minimum of 30 seconds MUST elapse between disconnection of the first cable and connection of the last cable. A clean final connection must be made. Do not allow temporary contact.
- Always reconnect the battery positive lead first and the negative battery cable last, ensuring that there is a good electrical contact and the battery terminals are secure. Tighten the battery cable clamp to specification. See «TORQUE SPECIFICATIONS»(ref-167192-S42295439232004100800000) .
- Reset the clock.
- Enter the radio security code.
- Following reconnection of the battery, the engine should be allowed to idle until it has reached normal operating temperature as the stored idle and drive values contained within the ECM have been lost. Allow the vehicle to idle for a another 3 minutes. Drive the vehicle at constant speeds of approximately 30, 40, 50, 60 and 70 MPH for 3 minutes each. This may cause a driveability concern if the procedure is not carried out. This will allow the ECM to relearn idle values.
2001
See STARTING/CHARGING in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
2002
See STARTING/CHARGING in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.