Battery — disconnection and reconnection
Warning: Always disconnect the cable from the negative battery terminal FIRST and hook it up LAST or the battery may be shorted by the tool being used to loosen the cable clamps.
1. Some systems on the vehicle require battery power to be available at all times, either to maintain continuous operation (alarm system, power door locks, etc.), or to maintain control unit memory (radio station presets, Powertrain Control Module and other control units). When the battery is disconnected, the power that maintains these systems is cut. So, before you disconnect the battery, please note that on a vehicle with power door locks, it’s a wise precaution to remove the key from the ignition and to keep it with you, so that it does not get locked inside if the power door locks should engage accidentally when the battery is reconnected!
2. Devices known as «memory-savers» can be used to avoid some of these problems. Precise details vary according to the device used. The typical memory saver is plugged into the cigarette lighter and is connected to a spare battery. Then the vehicle battery can be disconnected from the electrical system. The memory saver will provide sufficient current to maintain audio unit security codes, PCM memory, etc., and will provide power to always hot circuits such as the clock and radio memory circuits.
Warning: Some memory savers deliver a considerable amount of current in order to keep vehicle systems operational after the main battery is disconnected. If you’re using a memory saver, make sure that the circuit concerned is actually open before servicing it.
Warning: If you’re going to work near any of the airbag system components, the battery MUST be disconnected and a memory saver must NOT be used. If a memory saver is used, power will be supplied to the airbag, which means that it could accidentally deploy and cause serious personal injury.
Disconnection
3. To disconnect the battery for service procedures requiring power to be cut from the vehicle, loosen the cable clamp nut and disconnect the cable from the negative battery terminal (see illustration 4.1). Isolate the cable end to prevent it from coming into accidental contact with the battery terminal. After disconnecting the negative battery terminal, it is OK to disconnect the positive terminal.
Reconnection
4. If both terminals are disconnected, always reconnect the positive battery terminal first, then the negative battery cable. After reconnecting the battery, perform the Power-train Control Module (PCM) idle learn procedure.
Powertrain Control Module (PCM) idle learn procedure
5. Make sure that the PCM learns the engine idle characteristics after you perform any of the following procedures:
6. Disconnect the battery.
7. Replace (or reset) the PCM.
8. Replace the throttle body.
9. Replace the Idle Air Control (IAC) valve.
10. Remove the No. 6 (15 amp) PCM fuse (in the engine compartment fuse and relay box).
11. Remove the No. 19 (120-amp) BATTERY fuse (in the engine compartment fuse and relay box).
12. Remove the PGM-Fl main relay No. 1.
13. Remove any of the wires from the engine compartment fuse and relay box.
14. Disconnect any of the connectors from the engine compartment fuse and relay box.
15. Disconnect the electrical connector between the engine compartment wire harness and the PCM wire harness.
16. Disconnect the battery ground wire from the transmission housing.
17. Disconnect the ground wire from the body.
18. Disconnect the ground wire from the cylinder head.
Relearn procedure
19. Make sure that all electrical components (air conditioning system, lights, rear window defogger, sound system, etc.) are turned OFF.
20. Start the engine, bring it up to 3000 rpm and hold it there, with no load (in Park or Neutral), until the radiator fan comes on or until the engine coolant temperature reaches 194-degrees F.
21. Allow the engine to idle for at least five minutes with no load on it and with the throttle fully closed.
Note: If the radiator fan comes on during this five-minute period, don’t include the time during which the fan runs as part of the five minutes.