The Nissan / Infiniti vehicles of these year use independent coils on plugs (also known as COP). There is 1 coil per cylinder.
The replacement process is very similar for the following vehicles with the same 3.5L V6. This process is for a 2002 3.5L Altima, but is very similar for the Nissan Maxima, Nissan Murano, Infiniti I35, and Nissan Quest (for the Quest, the wiper cowl will need to be removed to remove the plenum).
- 00-04 Infiniti I35 3.5L V6
- 00-06 Nissan Altima 3.5L V6
- 02-08 Nissan Maxima 3.5L V6
- 03-08 Nissan Murano 3.5L V6
- 04-09 Nissan Quest 3.5L V6
Replacement of ignition coils in these cars may seem intimidating for those who aren't frequently under the hood, but anybody with a basic tool set and a slight knowledge of cars can achieve this job.
Tools Needed:
T30 Torx Driver (for engine cover removal)
Pliers for vacuum hose removal.
10mm socket or wrench
12mm socket or wrench
Removing the front 3 coils is very easy. Simply remove the engine cover with the Torx driver, and the front 3 coils are immediately accessible.
To remove the rear 3 coils, you need to remove the intake plenum.
- Start by disconnecting the vacuum lines and electrical connectors all the way around.
- Remove the intake hose by the throttle body.
- Remove the support bracket behind the plenum (near the throttle body)
- Now you can remove the bolts and nuts holding the plenum down. Remove the 2 12mm nuts on the end, and the middle 3 12mm bolts holding the plenum down.
- From here you will be able to remove the plenum up and out of the way enough to access the rear coils. Make sure to double and triple check for any vacuum lines, electrical connectors, and harness attached to the manifold.
Installing is the reverse process. Just make sure that all of your vacuum hoses are installed and all electrical connectors are plugged in. When installing the plenum, check to make sure the wiring harness is not interfering with the installation.
For these models, also be sure to check the main ground cable. This cable goes from the negative post on the battery to the transmission, and can corrode and break over time and with engine movement. This is the main ground to check. If it appears corroded or damaged in any way, it must be replaced before proceeding to do any other electrical work on the car.