2010 Wrangler Sport 3.8 had a misfire on cylinder 6. Replaced coil, wires, and plugs and still had misfire. Figured I’d check the injector because I needed to do intake gaskets anyway. Found 4 of the 6 injector plugs corroded with cylinder 6 being the worst with a broken pin from the corrosion. Replaced all 6 injectors and their pigtails. Got it all back together and still has a miss on cylinder 6. Checked the codes and it has a P0206 injector 6 circuit open. Checked resistance and voltage drop of the circuit it was all good. Ohmed the new injector and it is in spec as well. Could the corroded injector have caused enough resistance to burn out the injector driver in the ECM?
2010 3.8 P0206
- Thread starter dbsnyder97
- Start date
Given the circumstances, it is possible that the corroded injector and the broken pin could have caused enough resistance to damage the injector driver in the PCM. Corrosion and bad connections can lead to incorrect signals being sent, which might overheat or stress the driver circuit over time.
Here are a few steps to further diagnose the issue:
Inspect the PCM: Check for any visible signs of damage or corrosion. If you have a multimeter, you can also test the output of the injector driver directly from the PCM to see if it is providing the correct voltage to the injector.
Wiring Inspection: Double-check the wiring harness for any other potential issues. Look for frayed wires, poor ground connections, or any other signs of damage further down the line.
Swap Injectors: If possible, try swapping the injector from cylinder 6 with one from a different cylinder (like cylinder 5 or 4) to see if the code changes to the new cylinder. If it does, then the issue could indeed be with the ECM.
PCM Reprogram or Replacement: If you've confirmed the wiring and injector are good, and you're still getting the P0206 code, it may be time to consider the possibility of needing to reprogram or even replace the ECM. @Wranglerfix can hook you up with a new PCM (https://wranglerfix.com)
Hopefully, one of these steps will help you pinpoint the issue. Good luck!
Thank you for the reply!
Do you have any info on the procedure to check the injector driver output directly off the pcm?
The only bit of wiring I haven’t verified is load testing the injector power from the injector plug to the splice in the harness. All the injectors are powered off the ASD relay and each injector just branches off the same brown white wire. If there were an issue on that side of the circuit it would have to be from the splice to injector 6 because I don’t have any issues with any other injectors. I will verify it just to check it off the list but at this point I am really leaning towards the ECM.
Unless something has changed, historically, the ASD output provides 12v+ to the coils and injectors, and the ECM controls the ground triggers. All the ground wires are connected to the ECM and switched on as needed (aka when it needs to inject fuel or fire the coil). You should - again unless something major has changed (I've rewired and made a few JTEC swap harnesses over the years) - you should see 12V+ at the harness with the ASD jumped (or keyed-on for the first few seconds). I have seen in a handful of situations where considerable corrosion has worked into a cracked/broken wire and go down a few inches of wire, causing some issue (if that's the case, just cut it out and replace).
You can use one of those Noid-light setups to see if the injector is firing. AutoZone used to rent them at one time, though I don't think this is the case anymore.
Yeah that’s how the circuit works. Power is supplied by a brown white wire off the ASD relay and each injector is spliced into that wire. The other 5 injectors, and everything else supplied power by that wire, are working fine so the issue would have to be from the splice to injector 6. The wire looked good when I put the new injector pig tail on so I don’t think the corrosion made its way into the harness. I still need to physically test that end of the circuit when I get off work just to be sure though. I was hoping there is a way to test the driver in the ECM with a multi meter so I have an actual measurement and I’m not condemning the ECM just based on process of elimination. As long as I’m right and the power side of the circuit is good the only thing I can think of that’s left is the ECM.
I agree with you, unless you noticed some serious corrosion, it's unlikely that just that wire from that splice is causing you grief. If you had one of the older DRB tools, I do think you can indeed fire individual circuits on the PCM (this is where those Noid lights are handy, though I'd imagine you could use any LED light, or even just a small LED diode itself... My old Snap-On one could do similar as well.
We used to (dangerously!) pull an injector and put the tip inside a clear hose and point that into a bucket, then fire up the engine and see if it was spraying (using an appropriately sized rubber plug for the hole in the manifold). Not the safest method, but at least we could somewhat quickly (and redneck-ly) determine if the computer was telling the injector to open up...
We used to (dangerously!) pull an injector and put the tip inside a clear hose and point that into a bucket, then fire up the engine and see if it was spraying (using an appropriately sized rubber plug for the hole in the manifold). Not the safest method, but at least we could somewhat quickly (and redneck-ly) determine if the computer was telling the injector to open up...