Q: How to check and replace Ignition Coil on 1995 through 2004 Toyota Tacoma?
A: For the external coil type, start by disconnecting the cable from the negative terminal in the battery with a proper and valid code for any security stereo. Then unbolt the coil connector and coil wire from the coil, take out the mounting bolts to install the coil for test bench use. For assessment of the primary and secondary coil resistances, employ an ohmmeter to connect the terminals in this manner: connect the positive terminal to the other terminal, and note down the reading measured which should be compared with the expected value in the specifications, and then connect the positive terminal with the high tension terminal thus giving the reading which should also be compared with the expected value. If the reading on the meter is different then the set values of resistance, then replace the coil. For replacement, disconnect the cable from the negative terminal once again, then if there is any, take away the heat shield, followed by taking out the bolts that are used to mount the coil, label then remove the wires that are fixed to the coil terminals, once done fit the new coil in the reverse manner. For the internal coil type, follow similar steps: unscrew the negative battery cable, remove the heat shield and next, they have to remove mounting bolts from the coil electrical connectors. Perform an olummy test on primary and secondary and replace the coil if they are faulty. As for replacement, it is required to do the same as in the previous step and additionally disconnect the negative battery cable, remove the heat shield, label and disconnect the wires, and remove the coil mounting bolts before installing a new coil in the reverse order. In a distributor-less ignition system, with the ignition key off, the electrical connectors from each coil should then be removed and the primary and secondary resistance measured with an ohmmeter and; if its fails the standard readings the coil must be replaced. For replacement, you need to remove the negative battery cable, you need to identify and detach the ignition coil's electrical connecters from every coil pack, detach the bolts that are holding the ignition on the mounting bracket and reverse the process to fit the new coil.