P0335 Crankshaft Position Sensor A Circuit Malfunction

[lksohm]

I did a continuity test at the PCM while I moved the wiring harness as much as I could and it never failed. I did remove and replace the subframe a while ago before the driving season. Maybe I did something when I did that. I will do a deeper dive inspection.
I will reach out to a semi local Cobalt DIY tuner and ask him to move my tune over if it comes to that. At least the LSJ PCM is available from ZZP unlike many of the other styles.

 

[Gtstorey]

Well, you have replaced the sensor so if it’s not the wiring that only leaves the pcm or the reluctor.

 

[Gtstorey]

I don’t think the $209 option at ZZPerformance is going to fix your problem. At that price they reprogram/tune your existing pcm. They do have a more expensive option with a core charge but that is probably for a working pcm. I doubt yours will qualify if they check it closely. But I might be missing something.

 

[lksohm]

I managed to get a hold of an engine harness from another '07 LSJ car. I tested the CPK circuit as best as I could with a multimeter, no issues found.
I cut this circuit out and transplanted it into my car using all the best methods (solder, heat shrink...).
Did a resistance check at the PCM plug through the CPK. Am getting the same 840 Ohms as I was before. Test start the car and can barely get the engine to sputter after 5 seconds of cranking.
Why would the issue get way worse now?

 

[Gtstorey]

Same P0335 Code all that is showing? Is the new section of the harness routed in a different location?

 

[lksohm]

I work evenings so my schedule is off from most people's.
Can a scanner connect to the computer with just the ignition on? I thought the engine had to be running for some reason.
The wires are routed in a relatively direct route from the PCM to the CPK. I did avoid things like the fuel pump for interference reasons. These wires have no shielding from the factory.
I will dig into this again before work tomorrow.

 

[G Atsma]

Scanning codes is done key on, engine off.

 

[lksohm]

Looks like I need a better OBDII scanner.
The only code beyond the evap ones is still the P0335.

I was able to get the car to fire up this morning after some fiddling with the new lines. It seems that there is an issue with the new wires. I was able to have the car fire right up and purr, then by moving the wires get it to almost die before moving the wires again and keep it running.

I'm not going to mess with used wires anymore, even if they are OEM. I'm going to get a new twisted cable pair copper wire the same size and run a new line. I will try to depin the connector and run it straight to the PCM.

I really appreciate all the input and help with this. I am learning a ton which is a big draw to this project in the first place.

 

[Gtstorey]

A bad wire between the pcm and ckp sensor would cause the P0335 code, but to be clear, you are clearing the codes and allowing them to retrigger when it registers the problem?

 

[Gtstorey]

Something like this is what would be what you need (or more likely, overkill). Unfortunately the order time through Grainger is a month 2 weeks.
CHAINFLEX Continuous Flexing Appliance Wiring Communication Cable: Shielded, Stranded, Gray - 2TZJ1|CF211-05-01-02 - Grainger

 

[Gtstorey]

Something like this would likely work also.
10 FEET 5M2619-20-2SJ TWISTED PAIR PTFE SILVER PLATED SHIELDED 20 AWG WIRE | eBay

Any known good twisted pair wire would likely work, but the shield will add a little insurance from outside interference.

 

[Gtstorey]

One more and I'll stop.
chainflex CF211-05-01-02 20 AWG twisted pair 2 conductor shielded cable | eBay

 

[lksohm]

Haha, I have been looking to get something just like that locally but haven't found anything.
I am going to the local engine builder in the morning and ask if he has anything for me. If I can't get anything shielded I'll get new quality lines and try to get the car up and going til something can get here from the interweb. Maybe just wrap some wires in aluminum foil...? lol

We only get 5 or so months of good driving season here in Iowa and I am tired of wasting it.

 

[Gtstorey]

Any progress?

 

[lksohm]

I have been waiting to post some confirmed good news but I'm not there yet.
I did completely replace the CPK circuit including the pins on the PCM connector. Pulled the connector apart and replaced them with one's from my spare harness. Had to wait a week before weather would let me test drive the car, made it 32.2 miles before it failed again. Same P0335.

I ordered a new computer from Flagship one

https://www.fs1inc.com/?gclid=CjwKCAjw9-KTBhBcEiwAr19ig-asPwAKZOP7RLujiAOOid_gMoL5Awyz5H9VIDp_zOgepSaO0fjWihoCFkYQAvD_BwE

This should be in this week or early next. It will be programmed to my VIN, just need to have someone with HP tuners carry my tune over for me. I was told by a semi local DIY cobalt tuner that he wasn't able to change the VIN on a PCM with HP Tuners. Seems odd but it is possible.

 

[Gtstorey]

It's confusing on what HP Tuners can and can not do on a new ECM. I've came across a lot of post on the HP T forums that make it just that more confusing.
However the Programming for a new ECM isn't just adding in the old VIN, it's loading in all of the info to make it work with the car's original OEM equipment. I don't know how much of this HP T gets with a "write all" but I think a lot of tuners are worried about bricking the ECM and don't want to try it.

 

[lksohm]

Can't say I blame them. The place I ordered from would be a plug and play option if I had a stock tune and stuck hardware.
I just hope this does the trick. If not it is back to the drawing board. Maybe the reluctor wheel is the only other possibility. At that point might as well be a new engine.

 

[Gtstorey]

Yes, after this it is pretty much reluctor wheel or a bad replacement sensor which doesn't seem likely from the checks you did.

 

[lksohm]

I am finally confident that I have this issue resolved.
I have not been updating this adventure as it has been frustrating enough to deal with as I fought it but wanted to give closure to the issue and help anyone with similar issues.

The fix was to replace the PCM. I bought a replacement from flag ship one www.fs1inc.com . I don't recommend these guys to anyone. They took nearly a month wen the guaranteed five business days or less. I used them because they claimed to write my VIN to the PCM and would be a plug and play option for anyone running a stock tune.

Next hurdle: Getting my tune onto the new PCM.
I have a few mods from my donor including a tune. I thought it would be as simple as moving a PDF from one SD card to another for anyone with HP tuners. I assumed wrong. After dealing with self proclaimed expert DIY tuners. I was out $100 for each PCM credits and $100 to the guy who couldn't get it done. Also, wasting over a month of driving season before he quit responding to my messages.

Found a semi local tuner who's shop name is Goblin Garage coincidentally. He did a great job at moving the tune over. He will be my tuner for everything moving forward. He also had to do a relearn on the crank sensor which required his snap-on scanner. HP tuners couldn't get it.

I have since put on about 450 miles with zero hiccups. I am using the car as my daily driver to make up for lost time. I do not know what killed the old PCM but the new one works as it should.

Thank you to everyone who helped me out. This forum is fantastic!