nissan4x4 Posted December 13, 2007 Share Posted December 13, 2007 I got a error code 21 today, and my chilton manual says it caused by the power transistor not sending a signal to the ECU. Where is the power transistor located and are they cheap and easy to replace. Link to comment Share on other sites More sharing options...
yozsi Posted December 13, 2007 Share Posted December 13, 2007 its actually the ignition module, its the gray box thing located near the coil with one connector and 3 wires. Link to comment Share on other sites More sharing options...
nissan4x4 Posted December 13, 2007 Author Share Posted December 13, 2007 its actually the ignition module, its the gray box thing located near the coil with one connector and 3 wires. could the power resistor cause a weak spark if it went out Link to comment Share on other sites More sharing options...
Simon Posted December 13, 2007 Share Posted December 13, 2007 Absolutely. Link to comment Share on other sites More sharing options...
nissan4x4 Posted December 13, 2007 Author Share Posted December 13, 2007 Absolutely. is it located on the mounting bracket with the coil or is it somwhere else. if you could please post pics of it location thanks Link to comment Share on other sites More sharing options...
Simon Posted December 13, 2007 Share Posted December 13, 2007 It's right behind the coil. It's a little grey box. It's got 1 electrical plug going into it, and is mounted with 2 screws. You can't miss it. Link to comment Share on other sites More sharing options...
nissan4x4 Posted December 13, 2007 Author Share Posted December 13, 2007 It's right behind the coil. It's a little grey box. It's got 1 electrical plug going into it, and is mounted with 2 screws. You can't miss it. i see this black box with fins on it thats right below the coil Link to comment Share on other sites More sharing options...
Simon Posted December 13, 2007 Share Posted December 13, 2007 Behind man. Toward the firewall. Link to comment Share on other sites More sharing options...
nissan4x4 Posted December 13, 2007 Author Share Posted December 13, 2007 Behind man. Toward the firewall. dude im bad at finding things but i dont see a gray box towards the firewall if you could please post a pic. thanks for helping a newb like me. Link to comment Share on other sites More sharing options...
Simon Posted December 13, 2007 Share Posted December 13, 2007 I'll see what I can dig up.... Link to comment Share on other sites More sharing options...
yozsi Posted December 13, 2007 Share Posted December 13, 2007 it will either look like this: or like this depends on what year and engine it is. Link to comment Share on other sites More sharing options...
Simon Posted December 13, 2007 Share Posted December 13, 2007 I didn't know there was 2 different types..... Maybe the one you described is the type you have. Link to comment Share on other sites More sharing options...
nissan4x4 Posted December 13, 2007 Author Share Posted December 13, 2007 (edited) it will either look like this: or like this depends on what year and engine it is. it the black one with fins on it. if it went out would you still get voltage thru it?cause my voly meter says 12.56 volts. would this stop the computer from receiving the signal as in a error 21.thanks so much Edited December 13, 2007 by nissan4x4 Link to comment Share on other sites More sharing options...
yozsi Posted December 13, 2007 Share Posted December 13, 2007 what do you mean voltage through it? you cant test the module just by reading the voltage, the only 2 tests are a resistance test, and a KV test using a scope. Its a transistor, so it is an amplifier, its there to increase the power sent to the coil. they can completely fail, or stop working when hot. i would just replace it, its cheap. Link to comment Share on other sites More sharing options...
nissan4x4 Posted December 13, 2007 Author Share Posted December 13, 2007 what do you mean voltage through it? you cant test the module just by reading the voltage, the only 2 tests are a resistance test, and a KV test using a scope. Its a transistor, so it is an amplifier, its there to increase the power sent to the coil. they can completely fail, or stop working when hot. i would just replace it, its cheap. i just priced one at $80.00 does that sound about right for price. Link to comment Share on other sites More sharing options...
yozsi Posted December 13, 2007 Share Posted December 13, 2007 yep, thats about going rate. maybe snag one from a JY first, prolly get one for 5 bucks. Link to comment Share on other sites More sharing options...
nissan4x4 Posted December 13, 2007 Author Share Posted December 13, 2007 what dont get is the coil has a bright fire, but when it gets to the distributor it gets weak spark. and the distributor cap and rotor is all new. would this ignition module cause this. Link to comment Share on other sites More sharing options...
yozsi Posted December 13, 2007 Share Posted December 13, 2007 if you are getting a code for it its probably on its way out. did you make sure all of ignition wires are okay? maybe you need a new set, how are you confirming a strong/weak spark? Link to comment Share on other sites More sharing options...
nissan4x4 Posted December 14, 2007 Author Share Posted December 14, 2007 (edited) For the coil we stick a spark plug in the coil wire end and ground it on the engine block.all the ignition wires are about a 1,000 miles old, for the distributor we just take a spark plug out with the wire on it and ground it. Edited December 14, 2007 by nissan4x4 Link to comment Share on other sites More sharing options...
yozsi Posted December 14, 2007 Share Posted December 14, 2007 well, you are not gonna get as strong spark at the plugs than at the coil. there is so much resistance in the wires that the spark energy has dropped significantly. what are your symptoms, engine stumbling, low power, etc.... Link to comment Share on other sites More sharing options...
nissan4x4 Posted December 14, 2007 Author Share Posted December 14, 2007 well, you are not gonna get as strong spark at the plugs than at the coil. there is so much resistance in the wires that the spark energy has dropped significantly. what are your symptoms, engine stumbling, low power, etc.... engine doesnt start just turns over getting gas really weak orange spark from the distributor. Link to comment Share on other sites More sharing options...
yozsi Posted December 14, 2007 Share Posted December 14, 2007 well i would replace the ignition module, and make sure your ignition timing is good. Link to comment Share on other sites More sharing options...
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