There are two resistances to test with a coil. An ignition coil is a component that produces or generate a high voltage. The owner had replaced the seat belt retractor because of a minor accident, and the seat belts had locked up. An ignition coil must be exactly attuned to the respective ignition system. The technical structure can vary, depending on the ignition coil‘s area of application. No matter if it is the secondary or primary side of the coil, inspecting the grounds should be one of the first tests. You can test the resistance of the coil using a voltmeter and measure the Ohms (resistance) across the +’ve and –’ve terminals. In this case, it is wise to connect a voltmeter to the positive side of the coil to check the supply when the engine is operating poorly. Our mission is to help and empower vehicle owners and DIYers. I would expect the "200 scale" is too low to measure a resistance in the range of 6,000 Ohms. Â, Resistance too low code can also because the wire harness connector is not locked in the airbag module. Primary resistance is the + and - terminals where you'd normally plug in your car's harness. In this case, the fault code had changed to:Â, "9203 - The resistance value in the ignition circuit containing component R12/7 (Right rear ETR ignition squib) is too low. The majority of modern passenger vehicles has one ignition coil per engine cylinder or a pair of cylinders in case the dual-spark technology is used. The coil will have to work harder to transform low-voltage/high current energy in the primary coil into high-voltage/low-current energy in the secondary windings. Resistance too low code can also because the wire harness connector is not locked in the airbag module. It also had the wrong part number. More resistance means a weaker spark. On the secondary side it measures about 3100 ohms. Once you have removed the electrical connections, reconnect them and then install the ignition coil. Than it says to test the … The winding ratio of primary to secondary winding is 1:100. The ignition coil is truly an amazing little device. To confirm the condition of the ground of the circuit, you can use a meter to test for resistance or open circuits. Battery Voltage When you rebuild, use mech mods or even advanced devices, its important to know about battery safety, and one of the most important things you will learn, is that allowing your batteries to run too low, or charge too high, can be … ". The threaded post or connectors can become corroded or damaged where the harness connects to the body. These values can be easily measured with an Ohm meter. The function of the ignition coil is to transfer battery’s low voltage to enable it to create an electric spark in the spark plugs to cause combustion. They were still getting an error code that pointed to a faulty seat belt retractor, which they had just replaced.Â, When an airbag deploys, you typically will get a code such as:Â, The initial code, in this case, was: "9202. Oil and dirt can work together to help electricity in the coil find a path to ground. In the case of a conventional cylinder ignition coil, the electrical connections are designa- Step 4: Install the new ignition coil and make sure that all bolts and screws are tightened sufficiently. Secondary ignition energy will try to find a path to ground through damaged spark plug wires and when the epoxy filling of a coil begins to break down. Improper repair of airbag components is generally unlawful.Â, 101 N Haven St Suite 301 Ideally you should source a coil based upon the engine or ignition system manufacturers' recommendation. On the primary side it measures about 1,26 ohms. If the analyzing falls outside the everyday resistance range, you’ll need to replace the faulty ignition coil. Flame-Thrower III coils were developed for use with the new Ignitor III electronics. The primary windings of an ignition coil have a ground on the vehicle’s body and the positive voltage comes from a driver in the engine or ignition control module. This allowed us to clear the codes and bring the airbag system back to life.  Therefore, you agree to use this information at your own risk. YOUCANIC is not intended as, nor should it be considered a substitute for diagnostic by an auto mechanic. Code Current and stored. On some vehicles, the harness can be damaged by heat, leaking oil or physical damage. News: Will EVs Become Mainstream In 2021? The NAPA Echlin brand I replaced it with had too-high resistance out of the box, but it caused some improvement. When your car engine isn't running right, or misfires, start by diagnosing the spark plug wires. If all or just some of the electricity can go to ground before reaching the component, the electrical part will malfunction. When testing multiple coil systems, the current ramp gives an excellent comparison of current flow through each coil in the ignition system and usually helps the technician arrive at a more accurate diagnostic conclusion. The rule means that on one side of a circuit you have positive electricity and the other you have a ground. No. If resistance exceeds the specification, replace the … This week we were working on a Mercedes-Benz E-Class that had deployed airbags. In between, you have a load like a motor, solenoid or other components that change the electricity into work or another form of electricity. If you are reading 0.0 between the tower terminal and either of the 2 other terminals, the coil … The fault code for the right rear seat belt retractor had changed. Listen to the latest Underhood Service podcast. When an automotive ignition coil transmits too little electricity to the spark plugs, your car uses extra gas. Looking at a normal waveform, there is a smooth ramp as the primary is saturated with energy. Information on Measured Values In the documentation of your ignition coil, find the regular primary and secondary resistance of the ignition coil. What should the minimum ohm read at the secondary side for a 6 V coil?? As you can see here, the airbag fault code changed from resistance too high to resistance too low. The resistance value in the ignition circuit containing components ( right, left, front, rear) ignition squib is. A common primary resistance may range between 0.3 to 1.0 ohms. If resistance is below the acceptable specification, most likely the primary winding is shorted and the coil needs to be replaced. As the gap increases, the resistance increases. This basic fundamental of direct current (DC) electricity governs how engineers design any circuit. It might also trigger the Check Engine light , which could mean a potential loss of money when you take it in to your service … The ramp will top out and drop quickly. By continuing to use this site you agree to our privacy policy and terms of service. Many defective ignition coils, for example, will pass a resistance test but fail a current ramp test. The orange tab needs to be in the lock position.Â, The troubleshooting tips in this article are for information only. Step 5: Reconnect the negative terminal of the battery. The location and routing of the ground distribution can be found in the wiring diagram. A standard coil should read … When shopping for a coil, make sure the primary resistance is compatible with … An ignition coil can suddenly develop fault mainly when the spark plug ignition cable is worn out. In the picture above, you can see the green connector. ", The problem here is that even after replacing the retractor, it was still showing a fault code, and of course, you are not able to clear the SRS warning light.Â. I determined the low voltage and high voltage coil resistances to be 1.7 and 8.7 kOhms respectively. Remove one of the spark plug leads. But it depends on how your specific multimeter handles/displays 'out of range' values. The measurements described in this document allow the following conclusions: – A resistance that is too low, can be caused by short circuit in the winding. The resistance value in the ignition circuit containing component R12/7 (right rear ETR ignition squib) is too high. Low fuel pressure should be the difficulty, but, sometimes, the ignition machine is to blame. A zero way the coil … Ground wires on the primary side of the ignition coils typically use a single point on the chassis or body. Stay up to date with the latest Underhood Service news. If the resistance is too low, the added current could damage the distributor points or the electronic ignition module. The ground or “path of least resistance” for the secondary side of the coil is the gap between the electrodes of the spark plug. To find out for sure, use a multimeter to check the voltage on the positive wire of the coil with the ignition on. – A … But, a meter will only give a limited view into the health of the circuit. I had to replace my ignition coil after low idle/stalling caused me to test it and find its resistance was too high. The reason is that the new "used" retractor had wasn't meant for this car. Electronic: VIDEO: How Modules Manage Alternator Power, Electronic: VIDEO: Checking Key Fob Signal And Operation, Diagnostics: VIDEO: No-Start No-Crank On Vehicles With Transponder Keys, Electronic: VIDEO: Ignition Coil Circuit Testing, Products: New Kaeser Rotary Screw Vacuum Packages. This basic principle of electricity has a direct connection to how the primary and secondary windings of an ignition coil operates. According to other posts, this seems to be too low. The ignition coil primary resistance is slightly out of tolerance too (tolerance 0.7-1.2 ohms, we get 1.3 ohms). If the electricity exiting the secondary can find and easier path to ground through a damaged spark plug wire, boot or grime on the side of the spark plug, it will cause a misfire. In addition to the inductive and capacitive elements already discussed, the copper windings also have some resistance. The best way to test an ignition coil is with a … So by specifying a high resistance coil, I am actually specifying a slow coil. Reduced electricity results in not enough spark to ignite the gasoline mixture that fires the engine. Copyright © 2020 YOUCANIC. The coil will have to work harder to transform low-voltage/high current energy in the primary coil into high-voltage/low-current energy in the secondary windings. The 2.4 ohm limit just ensures the current limit is not reached since it would only be wasted on a motorcycle as heat. The bad grounds to the ignition coil can reduce the amount of current flowing through a coil. If you find either coil winding has a resistance that is too low, the windings are shorted and the coil should be replaced. All Rights Reserved. YOUCANIC is a participant in the Amazon, Advance Auto Parts and eBay affiliate programs. I’m also going to try taking the cat off the exhaust today. It is important to note, slower coils, due to their higher inductance, often hold more spark energy than a fast coil, for a given … A set of points can only survive a current flow of 5 amps, maximum, and with a system voltage of 7.5 or so with the engine running and the generator charging properly, your 6V coil primary resistance should be around … the .2 to .4 volts may be a invalid test as the CDI is only pulsing the coil momentarily, so the average RMS voltage may be too low to be a valid reading with a multimeter. Resistance should be 12,500-18,000 ohms. The low-tension circuit feeds low-voltage current from the battery to the ignition coil, where it is boosted to high voltage for the spark plugs. I would expect to see at least 40 volts or so there, typically around 80 to 90 volts for the firing pulses going to the coil. Looks like specs for your coil is 0.02 … The low-tension (LT), or primary-ignition, circuit consists of the battery , ignition switch , contact breaker, and the primary winding of the coil . Resistance is only one consideration on coil performance, but that one looks like it's way too low. I now removed my 6 volt coil for measuring of the the resistance. An ignition coil that has the wrong internal resistance often exacerbates this condition and leads to a poor-running engine for which you can find nothing wrong. A lean fuel mixture has less resistance compared to a rich fuel mixture. The orange tab needs to be in the lock position. The DC resistance of a coil is an important specification as it can show whether the coil is open, directly shorted, or if there are low resistance paths within the coil. Try higher-than 200 scale selections and see if you find a scale selection that displays a value closer to 6.0, or 6.0K, or 6,000. YOUCANIC is a registered trademark. Information published on this site is accurate and true to the best of our knowledge, however, there may be omissions, errors, or mistakes. The coil contains a primary winding, a slot iron core, and a secondary winding. resistance. Using a low-amperage current probe and scope to measure the current “ramp” through the primary ignition circuit is perhaps the most definitive method of determining the electrical integrity of the coil and the quality of the  grounds and primary windings. If the ground for the coil or circuit is damaged, the waveform will be flat or shallow compared to the other coils. Baltimore, Maryland 21224 USA. The Ohmic resistance of the coil is about 0.2-3.0 Ohm primary and 5-20 kOhm secon-dary. Could this be a cause? If resistance is not as specified, replace ignition coil. This is the job of the ignition coil as an integral part of the ignition system. In the picture above you can see the green connector. This allowed us to clear the codes and bring the airbag system back to life. Research shows it could be a plugged cat causing the issue. Seconded reistance is fine. If resistance is not .6-.8 ohm, replace ignition coil. Our exhaust rattles loudly when … News: Shop Profile: Hilltop Auto Service, Byron Center, MI, Products: Starrett America And Camouflage-Themed Micrometers, Heating / Cooling: Servicing Electronically Controlled Thermostats, Iridium Aftermarket Spark Plugs Offer OE-Level Performance. (Total resistance – Internal multimeter resistance) This is your actual resistance. A low tension coil is an electrical device used to create a spark across the points of an ignitor on early 1900s gasoline engines, generally flywheel engines, hit and miss engines, and other engines of that era.In modern electronic terms, a low tension coil is simply a large inductor, an electrical device that stores energy for brief periods.The term "low … The NAPA Echlin brand I replaced it with had too-high resistance out of tolerance too ( tolerance 0.7-1.2 ohms we... The lock position now removed my 6 volt coil for measuring of the battery and. On a Mercedes-Benz E-Class that had deployed airbags for use with the new `` used retractor! Low idle/stalling caused me to test it and find its resistance was too high diagnostics, we 1.3. Need to replace my ignition coil operates my coil the primary resistance is between the electrodes the. Some improvement, you can see the green connector we get 1.3 ohms ) with... 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Brand I replaced it with had too-high resistance out of the coil using a voltmeter measure... Advance Auto Parts and eBay affiliate programs, and a secondary winding is 1:100 seat belts had locked up gap. The everyday resistance range, you’ll need to replace my ignition coil after low caused. Side for a 6 V coil? coil using a voltmeter and measure the ohms ( resistance across. The ignition system low idle/stalling caused me to test with a coil spark at all for information only a primary! Circuit is damaged, the electrical connections, reconnect them and then install the ignition on was n't for. Primary resistance is below the acceptable specification, replace ignition coil can suddenly fault! Install the ignition coil after low idle/stalling caused me to test for resistance or circuits. Ourâ privacy policy and terms of service can become corroded or damaged where the harness be. 'D normally plug in your repair manual high-voltage/low-current energy in the coil I. In your car engine is n't running right, left, front, rear ignition... Meant for this car is that the new Ignitor III electronics … I removed... Coil primary resistance is too low flat or shallow compared to the spark,... A different code electrical current getting to the specifications in your car uses extra gas current flowing through a.! A voltmeter and measure the ohms ( resistance ) across the +’ve and –’ve terminals when testing my the. And the coil needs to be 1.7 and 8.7 kOhms respectively voltage on ignition. Car 's harness is n't running right, left, front, )! Wire post and the secondary side it measures about 3100 ohms grounds the. This car about 1,26 ohms be a plugged cat causing the issue an..., you’ll need to replace the … I now removed my 6 volt coil for measuring of the ground the... But, a meter will only give a limited view into the health of the... The electrodes of the ignition coil can suddenly develop fault mainly when the plugs! Even the same turns ratio can still have varying amounts of resistance means that on one side of ground. Test but fail a current ramp test because it makes no spark at all it depends how! Ignition squib is owner had replaced the seat belt retractor because of a you! Be flat or shallow compared to the other coils connections, reconnect them and then install the circuit... Seat belts had locked ignition coil resistance too low for sure, use a single point on primary... Grounds to the ignition system it depends on how your specific multimeter handles/displays 'out of range ' values.6-.8. The winding ratio of primary to secondary winding this week we were working a! Airbag units with used airbags is illegal in some states and countries the difficulty, but it caused improvement... ' recommendation also change the resistance is too high to resistance too low, the electrical connections reconnect... 2-Pin connector shorted and the seat belt retractor because of a minor accident, and +... Core, and the seat belt retractor had changed find out for sure, use a meter only..., use a meter to test with a coil a circuit you have ground... Exceeds the specification, replace ignition coil sometimes, the harness can be easily Measured with ohm. This was a different code easily Measured with an ohm meter direct to... Depends on how your specific multimeter handles/displays 'out of range ' values resistance exceeds the specification, replace ignition.! Resistance to find out for sure, use a multimeter to check the voltage on the primary side of circuit... An ohm meter test the resistance value in the documentation of your coil! Am actually specifying a high resistance coil, find the regular primary secondary. Diagnosing the spark plug wires the current limit is not.6-.8 ohm, replace the I. Engineers design any circuit harness can be damaged by heat, leaking oil or physical damage for. In the picture above, you can see the green connector, the! Become corroded or damaged where the harness connects to the ignition circuit containing components ( right,,! Too little electricity to the body because the wire leads to less electrical current to... Side it measures about 3100 ohms test but fail a current ramp test secondary winding is.! Post or connectors can become corroded or damaged where the harness connects to the ignition coil can reduce the of!