2004 TJ P0351, P0352, P0353 Codes. Jeep will Idle but won't go above 2K RPM.

[Mike Patterson]

I’m having an issue with my 2004 TJ, Manual Trans 4.0. The Jeep sat for about a year(Needed a clutch and a few other things) and when I test drove it around the block, it felt like it had a Miss but had no codes. I figured I would try changing the plugs. I changed the plugs and now it idles good but once I go beyond 2000 rpm's, the engine sputters and the CEL Light comes on and throws the P0351, P0352 and P0353 or a combination of at least 2 of them.

I’m on my 3rd set of plugs, I’ve tried 3 different Coil Packs, I have now sent the PCM off to get checked. It checks out as Good. I’ve changed the Coil Pack Connecter, I’ve Changed the Fuel Injectors, Battery is Charged. The TJ has Fresh Fuel. Does anyone have ANY Idea what the issue might be?

I’m wondering if anyone else has run into this issue and how you resolved the issue. Please let me know. Thanks.

 

[ItchyDong]

Have you followed the troubleshooting steps in the manual? I just read through them and they’re actually pretty good. Usually they suck.

Something I would add to this is to be certain your battery is in good condition, but more importantly that the alternator is providing 13.5 volts to the battery posts while running. If you have an underperforming alternator and a junk battery, she's going to have trouble making a healthy spark.

EDIT: Make sure to use an incandescent test light. NOT LED.

EDIT 2: You can probable skip step 2 if you don't have a bi-directional scan tool. It can be assumed you have 12 volts to the coil rail through the ASD being that it runs.

 

[TJ Jim]

Sounds like you need to chase the wires from the coil pack back to the pcm.

 

[ItchyDong]

Sounds like you need to chase the wires from the coil pack back to the pcm.

I suspect that's exactly what the troubleshooting guide would have him do.

 

[macleanflood]

ODB live data would help a lot with troubleshooting.

-Mac

 

[Mike Patterson]

Have you followed the troubleshooting steps in the manual? I just read through them and they’re actually pretty good. Usually they suck.

Something I would add to this is to be certain your battery is in good condition, but more importantly that the alternator is providing 13.5 volts to the battery posts while running. If you have an underperforming alternator and a junk battery, she's going to have trouble making a healthy spark.

EDIT: Make sure to use an incandescent test light. NOT LED.

EDIT 2: You can probable skip step 2 if you don't have a bi-directional scan tool. It can be assumed you have 12 volts to the coil rail through the ASD being that it runs.

Over the weekend I did jump the powered coil wire(Dark Green/Light Green Stripe) directly to the Battery and still had the same issue. In my opinion the only thing that I haven't done yet is to swap out that part of the Harness. I know I have to get either a 03 or 04 Harness but does the donor have to be a Manual Trans as well or no?

 

[ItchyDong]

Why did you jump power? Were you missing power to the coil? If so... that's a huge clue.

I have no clue on the harness. I wouldn't replace a harness before I had a reason to. Who knows what condition the donor harness is in.

 

[Mike Patterson]

Why did you jump power? Were you missing power to the coil? If so... that's a huge clue.

I have no clue on the harness. I wouldn't replace a harness before I had a reason to. Who knows what condition the donor harness is in.

I jumped it to have a consistent voltage with the thought that there might have been a short/voltage irregularity to the coil pack that was possibly causing the issue. I've been just trying to rule things out as far as what the issue is.

 

[ItchyDong]

Well, if it were in my shop, assuming everything you've said is correct up until now:

• I'd, one at a time, back probe pins 1,3,4 with a t-pin on the coil connector while disconnected. With the key off and incandescent test light connected to battery positive, touch the t-pin on each of the control wires. Test light SHOULD NOT light. You're testing for a control wire shorted to ground. 99.9% this isn't your issue, but it's too easy to test.

• Connect connector. With incandescent test light still connected to battery positive, touch the t-pin. (CHOCK THE WHEELS) Have a helper start it, turn the A/C on, turn the bright lights on (load the electrical system), put in drive, stand on the brakes, and raise the rpm slightly. Put the engine under a load. The test light should flash on each of those pins (1,3,4).

• If it doesn't flash, you either have a broken wire, corrosion/bad connection, the PCM is losing 12 volts via a bad power source or faulty alternator/battery dropping below 12v under load, PCM is losing ground when under a load, bad crank or cam sensor (goes bad when it gets hot or certain rpm, further troubleshooting required) or lastly, a bad PCM.

I don't have a go-to answer for you. These troubleshooting procedures are all assuming your ASD relay circuit is in good condition as you've described, and the coil pack/coil plug/spark plugs are installed correctly and working properly. This test will take you no more than 10 minutes.

I wouldn't discount the cam and crank sensors. They have a lot to do with spark and fuel delivery. I'd test those under load with a warm engine as well before I blindly threw a junkyard harness or PCM at it.

 

[Mike Patterson]

Well, if it were in my shop, assuming everything you've said is correct up until now:

• I'd, one at a time, back probe pins 1,3,4 with a t-pin on the coil connector while disconnected. With the key off and incandescent test light connected to battery positive, touch the t-pin on each of the control wires. Test light SHOULD NOT light. You're testing for a control wire shorted to ground. 99.9% this isn't your issue, but it's too easy to test.

• Connect connector. With incandescent test light still connected to battery positive, touch the t-pin. (CHOCK THE WHEELS) Have a helper start it, turn the A/C on, turn the bright lights on (load the electrical system), put in drive, stand on the brakes, and raise the rpm slightly. Put the engine under a load. The test light should flash on each of those pins (1,3,4).

• If it doesn't flash, you either have a broken wire, corrosion/bad connection, the PCM is losing 12 volts via a bad power source or faulty alternator/battery dropping below 12v under load, PCM is losing ground when under a load, bad crank or cam sensor (goes bad when it gets hot or certain rpm, further troubleshooting required) or lastly, a bad PCM.

I don't have a go-to answer for you. These troubleshooting procedures are all assuming your ASD relay circuit is in good condition as you've described, and the coil pack/coil plug/spark plugs are installed correctly and working properly. This test will take you no more than 10 minutes.

I wouldn't discount the cam and crank sensors. They have a lot to do with spark and fuel delivery. I'd test those under load with a warm engine as well before I blindly threw a junkyard harness or PCM at it.

Itchy, thank you for the well thought out reply. Much better than most. The Cam and Crank sensors are also new. I forgot to add those to the "List" of things that I've tried so far. I'll go through your suggestions tomorrow. I'll let you know how it goes.

 

[ItchyDong]

No problem. Keep me posted. I'll help walk you through the next steps too. There's always a way to test and isolate this stuff.

 

[Mike Patterson]

Well Itchy, I went through the harness on the passenger side. Everything looked good. I went through your test's and everything checked out. I had a buddy looking over the motor after everything was done. Still had the same issue. Hit 1900 rpm's, got the 2-3 coil codes. Crazy! My buddy then grounded the PCM to the tub, AAAAAANNNNNDDDDD... everything went back to Normal! So for whatever reason, the 2 wires from the PCM that ground the PCM don't seem to be working. So I'm just going to run a wire from one of the bottom screws on the front of the PCM and secure the other side to the Tub.

Thank you for your input. I really do appreciate it!

 

[ItchyDong]

Well Itchy, I went through the harness on the passenger side. Everything looked good. I went through your test's and everything checked out. I had a buddy looking over the motor after everything was done. Still had the same issue. Hit 1900 rpm's, got the 2-3 coil codes. Crazy! My buddy then grounded the PCM to the tub, AAAAAANNNNNDDDDD... everything went back to Normal! So for whatever reason, the 2 wires from the PCM that ground the PCM don't seem to be working. So I'm just going to run a wire from one of the bottom screws on the front of the PCM and secure the other side to the Tub.

Thank you for your input. I really do appreciate it!

Excellent job! LOADED Powers and Grounds, people. Beautiful.

 

[ItchyDong]

It's cool to run a separate ground, but I would also clean up G105. After looking at the print, that's what your PCM grounds to, and there's a whole lot of stuff that grounds there as well.

 

[Mike Patterson]

It's cool to run a separate ground, but I would also clean up G105. After looking at the print, that's what your PCM grounds to, and there's a whole lot of stuff that grounds there as well.

Do you by chance know where those 2 ground wires that are grounded/bolted at G105 pin out within the 3 PCM connectors so that I can check them for continuity?

 

[ItchyDong]

Sorry for the delay. Looks like C1 pins 31 and 32 are your two grounds. I only breezed over this because I'm currently in the middle of something myself, but I attached all 3 PCM connector pinouts for you to verify.

Edit: Pin 4, C1 is your sensor ground. Hit that one too. Don't test for continuity with a multimeter. It'll burn you. USE A TEST LIGHT connected to battery positive.

 

[Mike Patterson]

Sorry for the delay. Looks like C1 pins 31 and 32 are your two grounds. I only breezed over this because I'm currently in the middle of something myself, but I attached all 3 PCM connector pinouts for you to verify.

Edit: Pin 4, C1 is your sensor ground. Hit that one too. Don't test for continuity with a multimeter. It'll burn you. USE A TEST LIGHT connected to battery positive.

It winds up to be a false alarm. After I jumped a wire from the firewall to the PCM, another jumper from the Neg Battery to the PCM, the issue still exists. I will check those pins for continuity and see what the result is.

 

[ItchyDong]

You need to be doing all tests while recreating the set condition. If you're doing any of the tests with the engine off or idling, the results are useless. Get it to fail, while testing.

 

[Mike Patterson]

You need to be doing all tests while recreating the set condition. If you're doing any of the tests with the engine off or idling, the results are useless. Get it to fail, while testing.

Got it.