What is pcm diode. 1st off, what is a diode? MY buddy told me it was to direct current in one direction. Test the diode with a multimeter for proper function. Oct 4, 2011 · After start-up, the voltage at this wire should be 0 volts, as the PCM grounds this circuit to allow the secondary coil to fire the intake-side plugs per normal operation. Essentially prevents back-feeding the PCM while Jump Starting if incorrectly attached cables are attached or similar. com FREE DELIVERY possible on eligible purchases Jun 3, 2015 · What is the purpose of the PCM Diode located in the underhood fuse box. I want to check the pcm power diode. After doing either of these tests, if you have battery voltage (between 12-14 volts), this should be a good indicator that your PCM is on and working. I can walk out in the cool mornings and start and drive my truck just fine. I went to ford to replace the diode and it had no continuity and What is the difference between F57B-14A604-A and F5TZ-14A604-A? The one in my car rn says F57B-14A604-A on it. I only have the one for the PCM Posted by Customer: 2009 Ford Crown Victoria Jun 30, 2019 · My 2002 ford explorer 4. First, we'll cover some basic information about what a PCM is and what it does. I went to ford to replace the diode and it had no continuity and Jul 21, 2023 · 1997 - 2003 Ford F150 - PCM Diode - I have a 2002 F150 with the 4. Jun 25, 2017 · The PCM power diode is put into the fuel pump and PCM relay power circuit to prevent power surge feedback into the circuit called flyback voltage then can be higher than normal operating voltage. Jul 27, 2009 · The engine compartment fuse box has a diode for the PCM. Learn how to do it right and ensure optimal engine performance. Mar 9, 2020 · The Diode is a Fuse Type (Single) located in the front of the Under-hood Fuse Panel. I only have the one for the PCM Posted by Customer: 2009 Ford Crown Victoria Feb 2, 2015 · The diode is nothing more than a one way check valve, it allows current to flow one way, I have gotten water in my PCM due to a leak in my windshield, blew dryed it out and I was back on the road. 0L keeps blowing fuse 41 under the hood. 3 6 speed. Dec 18, 2023 · Our comprehensive guide to identify and address Powertrain Control Module (PCM) issues in your Ford F-150. Even with good fuses and relays, a failed diode blocks power flow to the PCM, disabling engine start. We should have 12 volts on both sides. This article will explain how to test your PCM using a multimeter. Dec 17, 2003 · my diode for my PCM is melted. Have only driven it maybe 5 miles and parked it. Next day let my truck sit in the 100 degree Jun 14, 2017 · It is the diode under the hood in the fuse box number 36 or 37. When it comes to testing your PCM, you can use a variety of methods. Once this happens the diode will blow within a few days and require replacement before the Jul 21, 2020 · Maintenance Shop - Pcm power diode - Hey guys I'm trying to locate the pcm power diode on my 05 f150 and drawing a blank. Jul 21, 2023 · 1997 - 2003 Ford F150 - PCM Diode - I have a 2002 F150 with the 4. It had continuity so I put it in the pcm diode slot and truck runs good. Jul 6, 2021 · 1997 - 2003 F150 - No power to pcm diode or the top fuses - This is kind of strange as all fuses are good in this truck and relays, but the PCM diode, fuses 18,23,24 have no power over them with the key on or off. I am having issues with my PCM diode located in the fuse box under the hood. How can you tell if its good. If the diode is bad, it's possible the pcm relay is defective and shorted, as the diode provides power to the coil in the relay if I remember correctly. i know its stupid to mess with Jun 30, 2019 · My 2002 ford explorer 4. due to a backup camera short my pcm diode blew. 7 volts. Next day let my truck sit in the 100 degree See full list on mechanicbase. Check for aftermarket accessories causing overloads. The PCM circuit diode should show low resistance in one direction (forward bias) and high resistance in reverse. 2 V-6. Is it somehow integrated into the fuse box or am I missing something?. Learn about common symptoms, diagnostic steps, and Nov 10, 2007 · I found out this is called the PCM relay protection diode. Inspect wiring harnesses for damage or corrosion near the PCM and fuse box. where can i get another diode. The computer may get flyback voltage surge and may damage power circuits inside the PCM is the diode was not used or is shorted across letting voltage to flow both ways. Can someone please tell me what it is and where it is located? I suspect the reason for my problem to be a short in 02 sensor circuit. . Buy Ford F5TZ-14A604-A - DIODE ASY: Diodes - Amazon. I will check the diode outside of the BJB on the ohm scale. I have a 1999 f250 7. Replace faulty diodes with OEM parts to prevent recurrence. I took the one next to it from the a/c diode slot under the hood and tested continuity with my meter. Then, we'll walk you through the steps of testing your PC The PCM diode is located in the battery junction box. So if I go to my pcm power diode and trace the red/yellow What is the difference between F57B-14A604-A and F5TZ-14A604-A? The one in my car rn says F57B-14A604-A on it. To troubleshoot, test the diode with a multimeter for continuity and replace if faulty. We can exchange the PCM May 23, 2025 · A power-train control module, abbreviated PCM, is an automotive component, a control unit, used on motor vehicles. The PCM relay has the power to one side and a good ground. Next, I will need to check the PCM for power. 5-0. 3 Powerstroke PCM. Use a multimeter to test the diode by placing probes across it; a typical forward voltage drop is about 0. All did the same job, protect the system from reverse voltage. it's still working. Regardless of what name, size, or type it’s, a car fuse is a Nov 10, 2013 · 1999 - 2016 Super Duty - PCM diode NO START - ok so im new to diesels but my truck will not start. i recently was messing with the truck and pulled out the pcm diode and as i was putting it back in something sounded as if it grounded something out. I need one for my A/C currently I am missing the diode for the compressor. but if i take it out it won't start. I got the part number from the Ford Truck Enthusiasts forum but I didn't keep it because I can go to radio Shack and get a 6V 25Amp Diode for about a buck and put some male battery spade terminals on it and put the band end toward the incoming +12 and I'd be set. Fuse 30 under the dash is good and has power. I know it sends the voltage for the secondary air inj May 12, 2014 · Hello. My truck runs fine except it will not start on the hot days here in So Cal. the dealer? why did it melt? thank's!! A bad PCM power diode can interrupt the ignition circuit, preventing the 1996 F350 from cranking. One of the most popular is using a multimeter. Dec 2, 2022 · From your understanding of what the PCM is and does, you can tell what the PCM fuse means. 2nd, do I really need it? Jan 28, 2011 · Re: Ford F150 PCM Power Diode Depending on the year, it was a chronic issue for Ford. it is a 2000 7. Sep 26, 2020 · Hi. A hot, blowing PCM diode in the fuse box usually indicates a short circuit or excessive current draw. Every four months or so the truck will begin surging while pressing on the gas pedal. com What is the PCM diode? The PCM power diode is put into the fuel pump and PCM relay power circuit to prevent power surge feedback into the circuit called flyback voltage then can be higher than normal operating voltage. (Some blew for no reason) It can go anytime there is a reverse voltage, bad ground in the shop, triggered through the lift, spark from an air chisel on the frame, welding, jumper cables hooked up May 15, 2025 · I replaced the neutral safety switch (twice, the first replacement resolved the issue for a week), the ignition switch, the starter relay, and the PCM relay prior to finding that the diode was blown. You had an ugly oily mess, one quick test completely unplug the alternator all the wires replace the diode and see what happens. Get the most comprehensive guide for replacing 7. So if I go to my pcm power diode and trace the red/yellow Sep 26, 2020 · Hi. Using the meter, I will check for power on these fuses with the battery connected. Depending on the year, they had different types. 3 6 speed dually. I will check for continuity (ohm measurement) on circuits/components that are isolated. exe5e 9ecmgtej tf2zf vn81m jhcsj j093ush ge3nri 9qz2 ehfk fywym