Troubleshooting Starter Problems With a Hyundai Sonata

by Don Bowman


The electrical wiring system for a Hyundai Sonata starts from the battery and runs to a buss bar that distributes the power to multiple circuits. From the buss bar, the power is directed to the fuse for the starter and then to the starter relay. When the ignition switch activates the relay, the power will pass through the relay to the starter and operate the starter. The activation side however is somewhat more complex. In order to activate the relay the power goes from the accessory fuse to the ignition switch and then to the security alarm device. From the security alarm it must go to the neutral safety switch which prevents the car from starting in any gear except park or neutral. From this point it passes to the starter relay and to ground. When the starter relay is activated by the key the power passes through to the starter. A volt meter will be needed to perform these tests.

Checking the Battery

Set the voltmeter to 20 volts dc. Check the battery---it should have 12.5 volts or more. If it has less than 12.5 volts, the battery or charging system is suspect. It is possible for a battery to show 12.5 or better on voltage and a bad cell, which would kill the amperage output. Amperage output is needed to activate the starter. Put the voltmeter's negative lead on the negative battery post and the positive lead on the positive post. Have a helper turn the ignition to the start position. As he does, check the battery for voltage drop. The battery should not drop below 10.5 volts when the key is turned to start. If it does, it means that the battery has a bad cell and needs to be replaced. If it does not have a huge drop in voltage, the battery is fine.

Checking the Fuses and Relays

Check the fuse for the starter and the starter relay in the under-hood relay box on the driver's side fender well. If the fuse is OK check for voltage across the fuse. If there is no voltage, look at the main fuses in the box. If they are OK, then pull the starter relay and check to make sure that one female terminal has power. If not, there is a fuse block problem. If there is power to one terminal, have the helper hold the key in the start position and check for voltage to a second terminal. The second terminal will have voltage only when the key is in the start position. If there is no power then the problem is now in the ignition switch, security alarm or neutral safety switch. If there is power to the second terminal, skip to the procedure for checking the starter.

Checking the Starter

Turn the key off and check to make sure that there are 12.5 volts at the starter on the large diameter line. If the starter does not have 12.5 volts, there is a problem with the main positive wire from the battery or the battery terminal. If there was power, remove the small 16 gauge wire from the solenoid on the starter. Check this wire for power---it will only have power when the helper turns the key to start. If there is power, the starter is bad. If it does not have power, then there is a break or open in the wire from the relay to the solenoid.

Checking the Neutral Safety Switch

If there was no power at the second terminal at the relay, check the neutral safety switch on the transmission. Pull the electrical connector and check for power at one terminal just when the helper holds the ignition in the start position. If there is power, have him release the key from start and plug the connector back in. Have the helper step on the brake and hold the ignition key in the start position and move the gear shift slowly into drive and just wiggle it back and forth. If the starter will work when the gear shift is moved then the neutral safety switch needs to be adjusted or replaced. Some are adjustable and some are not. If it is adjustable when the bolts are loosened it should turn right and left a small amount. If so have the helper make sure the car is in park and hold the key in start while you move the neutral safety switch until the starter engages. Lock it down with tightening the bolts. Have the helper start the car. If the neutral safety switch does not turn left and right, it is not adjustable and the switch will need to be replaced.

Checking the Ignition Switch

If there was no power at the switch, then go to the ignition key, which is the next step in line. Remove the bottom cover on the steering column and check the yellow wire for power when the key is in start. If there is no power, replace the ignition switch electrical side. If there was power, now its time for the dealer because it is in the security system or computer. This requires expensive and specific computers to reprogram. When the car is taken in make sure that you bring your registration to prove you own the vehicle or they will not work on it if the problem is a security alarm situation.

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