Nissan: Solving Rotating Electrical Issues – UnderhoodService

Nissan: Solving Rotating Electrical Issues

Maybe the warning light on the dash has caught the attention of the customer who was lucky enough to make it to your shop, or not so lucky and their car needs to be towed, says Import Specialist Contributor Bob Dowie. Whatever the scenario, don't be too quick to jump to conclusions when diagnosing rotating electrical issues.

This month, we’ll be looking at alternator and starter problems on the Nissan line of vehicles. Unlike some of the other topics I’ve covered where we can discover suspension problems while a vehicle is on the lift, or detect necessary brake repairs during a routine service, starter and alternator problems will likely get the customer to your counter, or the car on a tow truck, with a solid complaint related to the vehicle not starting as it should.

Or maybe the warning light on the dash has caught the attention of the customer who was lucky enough to make it to the shop, or not so lucky as their car is being towed in having run out of battery power on the road. Whatever the scenario, the point is, the vehicle will usually have a solid complaint attached. But don’t be too quick to jump to conclusions.

Like any other job, start at the service counter, as getting answers to the right questions is important to a successful repair. Whenever someone starts the conversation with: “My car doesn’t start,” my first question is “How did you get it here?” From there, you can talk about how they got it started. Many times, you’ll learn that jumping the battery did the trick; other times it will be “I just tried it again and it started.”

I’ll then ask if they noticed the distinct “single click” noise heard under the hood when the key is turned to the start position, or did it click like a machine gun? Not too many customers are attentive enough to pick up that single click, but, if they do, it’s a pretty good bet that the starter contacts are failing. It’s not uncommon for this problem to be more prevalent on a damp morning and one that will not cause a problem for the rest of the day.

It’s also much more prevalent on the gear-reduction style of starter than on the direct-drive starters (Nissan uses both styles depending on the model). The fact that the problem may be intermittent makes the diagnosis a little tricky. We usually like to duplicate a problem to confirm the diagnosis but, in this case, we don’t always have that option and have to go with what we know. A good tech will take extra care in this case to be sure there are no poor connections at the starter or battery, and that the battery is up to the task as the starter is installed.

The starter contacts are available separately, so you’ll have to make the decision on the best route for the customer and your shop. We always recommend installing a rebuilt unit so we have a warranted part for the protection of both the customer and the shop. 

Speaking of the battery, before starting any diagnostic process on the starter or alternator, be sure the battery is charged and the cables are clean. You’re not going to return the vehicle to the customer without servicing the battery, so why not make it the first step in the process and eliminate the question mark.

Now, if the customer reported that the car made a sound like a machine gun, we know there was enough current to pull the solenoid plunger in, but not to hold it. If they tried to jump it with no success, they probably didn’t have a good connection with the other vehicle, or had a poor connection leading to the starter. Your challenge then becomes finding out why the battery is low.



Let’s first look at some starter concerns that are common to Nissan, some of which are more prevalent on older cars. With the average car being 11 years old and the long-term reliability of Nissans, they will certainly be finding their way to your bays. 

On V6-powered cars from the early to mid-2000s, if you’re faced with an engine that sounds like it’s out of time when starting, but runs well once it starts, check the battery ground wire routing to see if it’s passing over the crank sensor. If so, simply rerouting the ground away from the sensor will straighten it out. We do this on all cars that get a new starter. We relocate the ground to one of starter mounting bolts from the original bracket. When doing so, it’s necessary to enlarge the eyelet on the cable a bit, a task that’s easily taken care of with a tapered ream.

Another crank and no-start issue that can be challenging and may have you looking at position sensors involves the electrical part of the ignition switch. Nissan, like many other carmakers, uses a bypass-type ignition switch that turns off power to accessories that aren’t required for startup when cranking.

The problem occurs when the terminal that should have power in the start position, doesn’t. The starter terminal still gets power, so you’re faced with a strong crank and no-start condition. Sometimes, customers report that it seems like the car starts when they let go of the key, but you can’t count on that. The best place to test for this is at the start fuse in the underdash fuse box. With the key in the start position, this fuse should show battery power. If not, it’s a safe bet that the ignition switch is the culprit.



Another crank, no-start problem that has probably caused more wasted time than any other issue, is when the key loses its memory and the immobilizer does its job of preventing the engine from starting.

We’ve received lots of calls from shops that were fighting this one. The tip-off is that the injectors won’t get a ground signal from the ECU. Actually the best tip-off is the security light flashing on the dash as you try to start the car, but it’s easily overlooked.

This problem requires reprogramming the key, and, depending on your equipment on hand, you may be able to handle this in-house. Otherwise, it’s back to the dealer or calling in a well-equipped locksmith, if you’re lucky enough to have one in the area.

Moving on to the charging side of the system, things are pretty simple. As mentioned earlier, most of these problems will come in with a complaint that the charge indicator light is lit. But like the security light, it’s easy to overlook that the lamp is not lit in the “key on-engine off” check lamp mode.

I spend a lot of time reminding my techs to be sure all the warning lamps are operating whenever you start a car. Not only is the “lamp not lighting” an indicator that the alternator is failing, it sure won’t do its job of warning the driver that they’re running on battery power and will eventually be stuck on the road. This is not only inconvenient; it’s also a safety issue.

We should all be familiar with diagnosing a no-charge condition and the Nissans will present little challenge on that front. Whatever equipment you’re using now to diagnose alternators will do the job. Most jobs will be out the door with a quality, rebuilt unit, a fresh drive belt and a good battery service. It’s the tougher ones we’ll talk about here.

I mentioned the drive belt, and on the older Nissans you’ll see some belt adjustment assemblies that need some attention to get them functioning as they should or, in severe cases, at all. Trying to force the adjustment pulley with the adjustment bolt will often result in breaking the hard-to-obtain bolt or an unhappy customer returning with a belt noise. While the alternator is being replaced, be sure the adjuster moves freely; it’s a lot easier to service it while you’re there, rather than to have to go back later.



Nissan hasn’t been immune from harness problems that can affect the charging system. These problems can show up as a no-charge lamp, no-charge condition, or overcharging. 

We recently had a 2002 Frontier towed in with a no-charge complaint that resulted in the battery going dead on the road. The young man reported that the warning light did come on, but he didn’t make it the 20 miles needed to get to the shop. Since we start with the battery, it was obvious why there wasn’t much reserve available with all the cells being low. And, since the battery was not that old, a test battery was installed while the other one was topped up and charged. With the new battery installed, the charge light came on, as expected, and stayed on when the engine was started, and a quick check with a voltmeter confirmed it wasn’t charging.

Parts were ordered and I assigned a young tech to the job. To his credit, it was done in a timely manner; the new drive belt was installed and the adjustment mechanism was lubricated. The charge light came on with the “key on engine off” and went right off when the engine started. The problem was the 15.6 volts the alternator was delivering to a well-charged battery. This tech’s first thought was that it was a defective unit, but I quickly suggested he take a look at a wiring diagram and confirm the alternator is seeing what it expects.

This truck enjoys a simple charging system that made it an ideal teaching situation. With only three wires and a ground, the diagram is easy to follow, and with some thought you can conclude that three out of the four are doing what they should.

We know the charge warning light is working so we can safely assume that circuit is functioning, we have over 15 volts at the battery so we know the connection is solid between the alternator and the battery, and we know the unit is grounded and the ground strap is secure. That has us looking at the green/black wire. The diagram tells us we should have battery voltage at all times. A quick check at the alternator shows no voltage. The diagram sends us right to fuse 36 in the underhood fuse box where we find the expected battery voltage. So, we know why we have an overcharge condition, if the regulator doesn’t know what the current state of charge is, it will give you all it can. 

Now that we found the problem, we had to come up with a fix that would best serve the customer, which, in this case, meant a reliable, affordable repair. We checked at the likely places for a bad connection. We had current through the fuse box to the harness and solid connections at the alternator. We gave the harness a good visual inspection for chaffing or pinching, and found nothing.

Faced with the option of accessing and opening the harness to look for the problem, or the more cost-effective choice of running an additional wire from the fuse box to the alternator, the customer chose the less-expensive method. Good work habits and careful routing resulted in a solid repair that should last as long as that truck.

I mentioned that this 2002 Nissan pickup has a simple charging system, and the good news is little has changed in the basic operation of the system. The later-model cars have adopted what Nissan calls “power generation voltage variable controls.” This system monitors battery current and varies voltage to the regulator, reducing the load on the engine and resulting in better gas mileage. If there is any problem with the new system, the fail-safe is to let the internal regulator control output as it did in 2002.

I’ll leave you with the usual words. This article certainly doesn’t have all the answers, but I do hope it gets you thinking. And, if you’re a young tech, I hope it shows you that it’s always easier to diagnose a problem after you’ve looked at and understand the wiring diagram. After all, it’s your map of the system.


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