ZZP 3800 1.0 PCM

Get all the benefits from your 3800 GTP or Grand Prix with the ZZP 1.0 PCM. ZZP PCMs ship fast and give the most requested and sought after features from a PCM tune.

zzperformance.com

May be worth a look.

 

decent experience with these folks Bill ?

 

Speaking from experience you can sub in another PCM from the same generation W-body car with the same 3800 engine as a test by first disconnecting the battery and completely unplugging the BCM under the dashboard. All the anti-theft is handled by the BCM and it only sends out a fuel/starter disable to the PCM via the CANbus under a panic event (IGN tamper, VIN mismatch with the PCM) so without it the PCM allows a start and throws a SECURITY message in response to the missing BCM data. I did this on my 03 LS to isolate a bad quad driver pack in the PCM itself.
PCM failures are rare however not unheard of, mine was the result of a pinched wire when I replaced the intake manifold that killed the injector driver IC. Swapping in a junkyard PCM as a test is far cheaper than the $150-$250 for another PCM. A word of caution: if the BCM isn't completly disconnected and it sends a panic stop fuel/start message to the donor PCM it will remain disabled until reset by the BCM on the next start cycle provided it does not see another panic event, found this out the hard way.

 

Thanks for the testing tip Brhat...! I may try to find one out of a local yard and test it. I've got one or two more checks to do, so I can satisfactorily close the loop on an possible broken wire/ missing ground issue, before I pull the trigger on a test PCM or a replacement but that is a grand idea you posed and could prove helpful.
thanks again !

 

I got my pcm from OverKill Motor sports. They no longer support 3.8 or 3.9l V-6. Have had my tune for many years and am very satisfied. ZZP has been around for years and I have purchased from them but not there pcm.
Personally I would trust ZZP over Flagship 1. Check Flagship 1 BBB reviews before you purchase form them.

 

@adm750 : Did you install an ACDelco/GM Cam Sensor? I know I've seen cases on other Forums where using an off-brand Sensor can result in unreliable performance.

 

Wondering if the timing chain has jumped, I learned the hard way one tooth off is enough timing error to prevent a startup.

 

Thank you for all the responses.

@Colt Hero - no, I used an aftermarket one. But the original one is actually good. I only replaced it as preventive (1x fault code) but I've never seen a cam sensor give a cranks/no start. Only a stall at stop, but car always restarts. Maybe these behave differently. Owned plenty of GM's but all pre 90's.
I certainly agree with your views on aftermarket sensors in key places where OEM is well worth the spend. My euro car experience has seen that scenario quite often....unfortunately...

@Brhatweed - shoot... really hadn't thought of that. I've experienced jumped timing, and they've failed to start, but all the elements were there so you get this odd struggling kinda half @$$ attempts to fire the cylinders. I can't get the injectors to turn on, (unless I manually ground them...) but maybe no-start is a symptom if the timing signals aren't correct. I'll have to check that.

@Bill58 - thanks for the feedback. yeah, F1S reviews are interesting reads. LOL. yikes.... 😬

 

@Colt Hero - no, I used an aftermarket one. But the original one is actually good. I only replaced it as preventive (1x fault code) but I've never seen a cam sensor give a cranks/no start.

I think I read somewhere once that the Cam Sensor ... if it fails ... can actually be inferred by the ECU ... but the Crank Sensor is the one that ... if it fails ... can cause an unrecoverable No Start.

The Timing being off could certainly cause the No Start, but what is the history of these Engines with Timing Chains jumping or breaking? Isn't it a single-chain system? I have a Single Timing Chain on my 2002 and it's still the original Chain at almost 255,000 miles. @adm750 : how many miles on this Engine? And has the Oil always been maintained properly?

Can you do a quick Compression Test on the Cylinders? If the Chain slipped (or even broke), you might have zero Compression ... although it seems unlikely sitting still after a successful drive just moments before ...

 

@Colt Hero - thanks again for the info. I have not done a comp test on all cylinders. Agree - unlikely with it just literally having been started / driven, shut off and filled with fuel, restarted / driven back home and turned off again. Might try to do that tonight.

this car has maybe 140k on it. Oil has been done at regular intervals (my in-laws were the PO) and my son and I just changed it about a month and a half ago. No s#!t, like a week before it failed. LOL. It left him stuck the weekend I was at Watkins Glen with the team which was at the end of May. Since then, I've been buried with work and travel so it's been touch and go getting all the testing done to dial in on this. It's been OTR for almost a month now.

I take it you can re-flash a used PCM, right ? I hate to make a $250 guess. Thought of getting a salvage yard unit, pulling BCM, and seeing if car starts on the used PCM. if it does, I know a guy who has the Tech2 and a laptop with the latest updates...lol

 

@Colt Hero -
I take it you can re-flash a used PCM, right ? I hate to make a $250 guess. Thought of getting a salvage yard unit, pulling BCM, and seeing if car starts on the used PCM. if it does, I know a guy who has the Tech2 and a laptop with the latest updates...lol

I'm sure it's doable ... but I've never done it. Don't have the proper tools. Maybe all that needs to be done is just patch in your VIN# somewhere. I've seen where that's worked for people installing a junkyard radio in Gen-2 (2010-2017) Equinoxes. Existing system will reject the "new" radio as an "invader" because its VIN# does not match.

Really hate how Manufacturers make it so difficult for Owners to do their own repairs. We have OBD-2, but they could do so much more. In your case ... you should be able to just plug in the junkyard ECM and it should boot up ... start pinging the other Modules on the vehicle ... and they should respond back with who they are, and what they know about their environment ... and then the ECM should just 'join the group' accordingly. Plug-n-Play ... nice and easy. As long as there are at least two Modules executing with identifying information, the Module trying to join should be able to get that information and assimilate.

 

@Brhatweed - "Speaking from experience you can sub in another PCM from the same generation W-body car with the same 3800 engine as a test by first disconnecting the battery and completely unplugging the BCM under the dashboard. All the anti-theft is handled by the BCM and it only sends out a fuel/starter disable to the PCM via the CANbus under a panic event (IGN tamper, VIN mismatch with the PCM) so without it the PCM allows a start and throws a SECURITY message in response to the missing BCM data. I did this on my 03 LS to isolate a bad quad driver pack in the PCM itself. "

well, I can semi-confirm that this test does not work on 2004 Impala

Found a 2004 Impala 3.8 PCM (under 60k mile vehicle). Disconnected batt, unplugged all connectors to BCM, r/r the original PCM and swapped in the donor unit, reconnected battery. Key on, all dash lights come on and the security light never came on. Tried to start and nothing...no crank at all....no click, no nothing...

swapped everything back to original state.....car cranks and will not start. Security light does not flash, it's steady like usual.

unless the donor PCM is garbage, but...whatever. back to square one.

 

swapped everything back to original state.....car cranks and will not start. Security light does not flash, it's steady like usual.

Forgive me if I'm suggesting something really dumb here, but ... this isn't the dreaded SECURITY (PassLock) problem locking you out, is it?

Whenever my 2002 put the SECURITY message up, it didn't turn over at all ... and then I'd wait 10 minutes ... and it started.

And it never flashed "SECURITY" ... it was always solid/steady.

Are there different "flavors" of the PassLock SECURITY issue?

 

If you were in Minnesota I'd make a service call

 

thought is much appreciated my northern friend.

All good, just getting a bit frustrated with this is all. But....everyone has given me some good things to consider and I appreciate that. Especially for this being my first post. The Impala forum reminds me alot of Bimmerforums and our E39 group. Lots of people with solid knowledge try to help. Now the E70 side of that is like a graveyard for posts to go die a lonely death in. hahaha

 

@Colt Hero - hey Colt ! That's a great thought, and I have been really suspect of that PassLock issue. With everything I have read, the failure has always been described as a no crank (no start of course...) with the security light flashing when it goes into protection mode. Unless I'm missing something, and I well could be.

The bypass methods I've read have more flavors than the ice cream aisle at the grocery store...LOL...so I'm reluctant to try to skirt it. Now that you mentioned it though, I'm going to revisit that potential failure and the repair.

I am going to order a PCM anyways so it has the latest software and take that out of the equation. Why not...they aren't that much. The only missing component here, keeping the car from starting, seems to be grounding the injectors when cranking the vehicle.

Thank you though for keeping the mind juices flowing.

 

@adm750 : just an FYI ... I had the SECURITY issue cropping up with my 2002 (bought brand new, BTW) ... back in 2005-2010 timeframe. It would happen to my wife off an on. First time it happened I had to leave work to go "rescue" her. By the time I arrived (30+ minutes later), the Engine started right up. After that, I found out just waiting 10 minutes allowed the Engine to start, so that's what I told her to do ... while I searched for a solution. I read up on all the "solutions" ... but in every case, I was able to find someone online saying "the problem came back again".

So ... having no faith in any of the solutions ... I did what I so often do : I left well enough alone ... and waited for more information to surface.

But then ... when I bought my 2011 Equinox LT (V6) in January 2011, the wife took that vehicle and my daughter started driving the Impala to high school (2012/2013). The daughter got stuck once at the Mall ... I remember ... and I had to run over there. Again ... by the time I arrived, it started fine ... but she was afraid to drive it home that day. Well, she went off the college and the son started driving it to high school in 2014/2015. I don't remember him ever getting stuck with the SECURITY problem ... just a dirty Throttle Body that caused it to stall ... but I fixed that with some spray and paper towel. No more issues that I can recall.

When he left for school, I started driving it as my everyday work commuter. I've never had the SECURITY problem in 8 years now!

And if you count my son's time driving it ... that's 9 years with no SECURITY problem.

So ... I never cut any wires, replaced any Ignition Blocks, or re-programmed any BCMs ... and the problem just stopped ... seemingly on its own!

To this day ... I still don't know what was causing that SECURITY issue. Maybe it had something to do with my wife's (or daughter's) keychains? They both had several keys and other "ornaments" on their chains, while mine (and my son's) just had what we needed. OR ... it could've been some weird tendency either of them had in how they were starting up the Engine?

Who knows? But because of my experience with this SECURITY issue ... I don't think the "solutions" are the answer ... because ... I've gone almost 10 years now ... doing absolutely nothing! I almost tried the "cut-the-yellow-wire" solution (with the resistor) ... because it sort of made sense to me. Had I done that ... I'd be posting here (the last 10 years) that this "solution" fixed the problem for me ... when, in fact, it really wouldn't have ...

 

I had the same problem, the problem was that my daughter has no patience and could not wait 10 minutes. The more she tried the longer it took to get going lol That daughter has turned into her mother and no longer talks to me. Changed the sensor and no more problems. Dorman 924702. You know there was a recall and advise against hitting potholes would turn the car off when excess junk was hanging from the keys.

 

@Colt Hero - man, that's wild. I know what you mean. The VATS system on our old Vette did us like that. It failed one night and left my wife stuck at the office the night before we were heading out on a roadtrip. I popped over there, installed the bypass pigtail (which was rather gimicky but was all the rage back then and that I'd had in my toolbox for months and been meaning to install since she kept having this issue leaving her stranded...), and the car started right up.

We got it home, loaded for the trip and took off the next day. Left Florida that morning headed for Kentucky. Hit the Vette museum then jumped back in and continued on to Ohio, went all over in Ohio....then drove back to Florida the following weekend. We were gone for a week and put nearly 3000 miles on that car during the trip.

We get home....unload the car....and I get in it to go get ice. It goes into anti-theft and won't start. 😱. We did nearly 3k miles and it failed AFTER we get back home safely.

Needless to say Monday morning I called my long-time parts guy at Chevrolet and ordered a new VATS module.

 

so, to update the ongoing saga of the cranks/no starting Impala:

I did a dry compression test on cylinders 1, 3, and 5. All jumped up to nearly 180 right away and pressure holds. I figure if those 3 are in spec then I'm doubting the engine jumped time.

I was able to get to that 4th ground (unchecked from my original post...) and verify it was good. Retesting everything - I found voltage drop across all four grounds from the PCM, the ground to the block by the starter, the ground to the block under the ICM, and across the common splice, were all 20mV.

Sourced up a used PCM from a local yard out of another 2004 Impala. This one has the same Service No. as the original one in my car.
Got ahold of Keith at PCM for Less in Stow, Ohio. Great dude. He programmed both PCMs with the latest software and flashed the replacement one with my VIN. We talked about how to approach replacing it. "try it first with the old one in case it went 'offline' and was corrected with the software update. Prob won't work but give it a shot. If it doesn't start then fit the replacement, try to start it, and if it does nothing go ahead and do the security relearn"....

I took them home and did just that. The car cranked and would not start with the original PCM just like old times. ok...we kindof expected that result.

I fit the replacement PCM and it wouldn't crank at all so I had to do the security re-learn. Once it took, I'm back to exactly the same place I was before. The engine will crank but it will not start and I have no noid light at the injectors.

I pulled all relevant fuses and did a continuity test to ensure that even though they were unburned, they weren't broken in the plastic bodies. All were good.

I've reintroduced my self to square one. "adm this is square one. Square one this is adm...."

 

...and again, I'm going off the assumption that when PassLock intervenes, the vehicle will not crank at all.... This is what I've understood to be the norm if there is a PassLock / VATS issue. That's the only failure mode I've seen - no crank when it goes into protection. Please correct me if I am wrong...

 

@adm750 : two PCMs and no power at the Injectors ... probably not the PCM ... something common ... like wiring or fuses. Could you have missed a fuse ... like an in-line one?

It sure feels like a SECURITY thing ... if the Injectors are not firing at all.

Can you verify the ECM(s) are trying to output a signal to fire the Injectors? Do you know which output(s) they are? Maybe something is blocking the signal(s) from reaching the Injectors? Does anyone know if these signals go directly to the Injectors from the ECM ... or do they go through one or more "gates" beforehand?

Do we have Wiring Diagrams?

 

Have you tried a shot of starting fluid?

 

Hey Bill ! TBH, I have not. I'll snag a can on the way home tonight and give that a shot (pun intended...) and see what happens.

 

@Colt Hero - I have power to the injectors but the PCM is not grounding them. The noid light will not come on at all when cranking but I do have spark. Looks like each individual injector is grounded inside the PCM. One common power feed to all of them but each one has an individual return line to the PCM.

I do not know of an inline fuse anywhere, but I do NOT have any worthwhile wiring diagrams.

I'm not familiar with the 'bypass mode' (or IC Mode ???) these engines operate in at start-up until the PCM takes over so I'm going to do a bit of research on that too when I get off work.
I think I understand that a 5v signal is sent from the PCM to the ICM that triggers the ICM to switch and allow the PCM to take over spark timing. I'm assuming that might also include injector timing but have NOT confirmed that.

this describes that operation for a 3.4 engine: 2004 Impala 3.4 No Injector pulse

I'm going to try to find the wiring diagrams for the 3.8 and check these 'signals'. I suspect maybe I have a broken wire that may be stopping this hand-over (??) or at least may be interrupting comms between the components in the system. (heck...maybe I have a bad ICM ???)

again...I'm assuming the PCM is getting all the proper data since I can read engine RPM when cranking via my scan tool. Now, what it's actually doing with it is becoming a prolonged agonizing mystery. LOL

*note: not sure if I posted this last night but I checked resistance of all injectors last night (to ensure one wasn't shorted and shutting them all down) and all six were mid 12 ohm range.

 

GM 3.8L Ignition Control Module And Crank (3X, 18X) Sensor Test

GM 3.8L Index of Articles

easyautodiagnostics.com

A lot of reading but good info.

 

@Bill58 - thanks for that ..! I've done those test but reading that test page was a good refresher. This looks nearly identical to the test write-up I found but I manually turned the car over using the crank pully bolt to do the CMP and CKP signal tests. Works just the same and all components tested good, as did the powers and grounds.

But...and harking back to the GM Bypass ignition System signals,

, I need to find a way to find out where these wires below feed to the PCM, and how to test them:

• A- WHITEwire.
  • ECM control of ignition control module (after the 400 RPMs and above are achieved).
• B- TAN with BLACK stripewire.
  • 5 Volt BYPASS from ECM for Ignition Timing Control.
• C- LIGHT BLUE with BLACK stripewire.
  • CRANK Position Signal to ECM.
• D- PURPLE with WHITE stripewire.
  • Fuel Injection Control Signal to ECM.
• L- BLACK with RED stripewire.
  • Ground that ECM gets thru' the ignition control module.

I need to find out if the ICM is sending the reference signal(s?) back to the PCM so it will turn on the injectors.

I'm onto that next.

 

Manual says you can view a “Scan Tool Data List” (using the Tech 2?) that will show the “Ignition Mode” as either “IC” or “Bypass”

And … what are the “Driver Module”s 1-4 used for? What do they do? The “Driver”s are solid-state devices used by (apparently by the PCM?) to ground the control circuit of each Fuel Injector. The Tech 2 can display their state(s) in real-time. Normally, they show “Enabled”, but they can also be “OFF” (High Volts or High Temp) or even “Invalid”

 

@Colt Hero - wow..! thank you !!!

I didn't have a lot of time tonight to get into the trouble shooting. I did get into it a bit but I need to ensure I clarify the terminology. Like what is the "multi-way harness connector of the fuel injectors" . Is that the ICM connector Term P ?? the 80-pin clear PCM connector Term 24 ?? the 2-pin conn at the injector itself..? or the 8-pin connector that looks to come off the ICM right at the manifold on the pass side of the engine ??. So I just need to familiarize myself a bit then will proceed with those test steps.

Just for grins I did get to pull the ICM / coil / bracket assembly off the block tonight just to make sure the ground surface between the ICM base and the bracket was clean. It was a bit of a mess with aluminum oxide. Not the worst, but not my face look for sure. I cleaned that all off and reassembled it. Tried to stat it but it made no change. Didn't expect it to, but at least I took that out of the equation.

thanks again for posting those pages. Even though for a 2002, it's still helpful.

cheers all !!

 

Like what is the "multi-way harness connector of the fuel injectors" . Is that the ICM connector Term P ?? the 80-pin clear PCM connector Term 24 ?? the 2-pin conn at the injector itself..? or the 8-pin connector that looks to come off the ICM right at the manifold on the pass side of the engine ??

I think that’s their all-encompassing term for the harness with all the connectors serpentining between the ICM, Injectors, and PCM. The “P” pin is the “Ignition 1” Voltage from the ICM driving the three Coils.

Good thought cleaning that ICM … wonder if that thing could be failed internally? Not sure yet…

 

Well square-one isn't a bad place to be at this moment. The 20mv differential is not enough to be noticed, the fact you don't have any injectors firing is so with that have you checked for +12v on the injectors themselves? They are all fired via grounded collector and should have a steady +12v available from the pink wire on all the injectors thru the 15 amp FUEL INJ fuse located in the underhood box. Do you have the factory wiring diagram for the 3800 VIN-K cars? It is different than whats found in the Chiltons and other aftermarket DIY books.

 

@Colt Hero - thanks for the suggestion on Square-One's closeout ICM. I'd like to avoid buying things I don't need, but thought a cheap yard part might help me continue to rule out stuff.

I consent it's not the most logical way to approach it, but $30 is worth delaying me tearing the tape and corrugation off a bunch of harness sections looking for broken wires in the chance the output signal from it to the PCM is bad. 😂

Good idea - I will probably ping my friend for that Tech 2 this weekend. Why have 4th of July fun when you can doink around fiddling with non-running cars. haha.

@Brhatweed - I do have steady voltage at each individual injector connector. Just can get the PCM to ground them when it's supposed to. As the one-liner states, they are all at 'G' waiting on 'O'....

This is why I think I am missing that reference signal from the ICM ----> PCM that tells the PCM that firing the injectors is a GO. Just haven't figured out if there is an RPM limit that allows it to be created, or if it's supposed to be there when cranking, or at ignition on. Have not found that test yet. Maybe the Tech2 can see that ? Dunno at this point.

I do NOT have the factory wiring diagram for this model car. Which is rough because I had the full factory GM set for my k1500 truck and for the Vette. Their invaluable. I've searched on-line a very little bit, but my google-fu has been weak and poorly applied. Will dedicate some time to that this weekend as well.

thanks again for everyone's suggestions and help. virtual cheers/beers to all of you !!

 

Interesting find tonight.

I've checked all the inputs to the PCM and ICM from the crank and cam position sensors during my prior adventures with this issue. With the scanner reading engine RPM during cranking, I'm going to say all the input signals from those two sensors to the ICM and PCM are good (this is also based on the test plan Bill58 added and others I've found).

So I go to check all the wiring from the ICM outputs to the PCM for continuity with both the ICM and the PCM connectors disconnected from their respective modules. Checked were ICM terminals:
B to C1 BLUE 53
C to C1 BLUE 9
D to C1 BLUE 8
F to C1 BLUE 7
L to C1 BLUE 48

These all had continuity....so all good.

Next I checked the grounds (which I have verified before), but this time I am strictly isolating the harness by itself.

K to C1 BLUE 56 - good (and good to engine block)
K to C1 BLUE 57 - good (and good to engine block)
K to C1 BLUE 61 - open circuit (no continuity)
K to C1 BLUE 16 - good (and good to engine block)

As noted, they all had continuity EXCEPT for terminal K to C1 (Blue) terminal 61. Now, again, I checked these before and ruled them all out as an issue.

aw damn....I just rechecked the diagram....I was supposed to check terminal 60. I thought I was on to something. 🤣 🤣 🤣

*puts tools away, grabs bourbon and makes stiff drink....

Tomorrow is another day

 

@adm750 : have you verified your CKP inputs at the ICM yet? If the ICM isn’t receiving these, then they’ll be no Injector Pulses.

Also, you can probably force the System to stay in Bypass Mode (with ICM in control) if you can block the IC Timing Signal output from the PCM to ICM (or maybe it’s never getting set to 5V anyway)!

UPDATE: looks like you snuck a Post in just ahead of me … you think your CKP and CMP signals are good … but what if the ICM is “seeing” it but just not using it? I think it’s in control of the Injectors during initial Cranking, correct?

If you had the TECH 2 you could see all the status signals in real-time. I think it would make everything very clear to you … what state the system is in …

I’m no mechanic, but I’m leaning toward a bad ICM.

 

@Colt Hero - ha..! yeah quite a post I put up till you get to the end, right...! LOL.

got your message also. totally respect the concern you noted in the content.

I talked with my guy that has the Tech2 and we discussed forcing the system into bypass mode, we just weren't sure how to pull that off. More learning ahead

 

@Colt Hero - ha..! yeah quite a post I put up till you get to the end, right...! LOL.

got your message also. totally respect the concern you noted in the content.

I talked with my guy that has the Tech2 and we discussed forcing the system into bypass mode, we just weren't sure how to pull that off. More learning ahead

I think you just have to block the PCM’s output on the “IC Timing Signal”. The PCM sets it to 5V as soon as it’s ready to take over Injector Timing (and everything else). Until the ICM sees this input, it stays in “Bypass Mode”.

So … you could cut the wire, or block the pin (if that’s possible).