Lots of codes, thing a bad ECM?

Hello,

I have a few codes in my riv, I am thinking the PCM is bad.

They are as followed:

P0123 - "Throttle Position (TP) Sensor voltage high"
P0341 - "Cam/Crank Error"
P0321 - "Spark Reference Circuit"
P1630 - "System Voltage High or low"
P0117 - "Engine Coolant Temperature (ECT) sensor - low temp. indicated"
P0118 - "Engine Coolant Temperature (ECT) sensor - high temp. indicated"
P0140 - No Description Available
P0137 - No Description Available
P1571 - Traction Control Desired Torque Out of Range
P0122 - "Throttle Position (TP) Sensor voltage low"

Parts I have replaced so far Ignition Control Module, Engine Coolant Temp Senor, Crank Sensor, Cam Sensor and I have redone all of the groundings between the battery to body and body to block.

Before replacing any other parts I want to know if someone has seen these before to have caused a problem (sometimes one code leads to another...).

Car does have very limited survivability problems to report with all codes.

Random misfire (once every few minutes on Cylinder 1, can't even feel it but reported by computer), rough idle, and it has a hesitation off of acceleration. Fuel pressure is right around 30 PSI running which seems to be normal, I don't think this car had a required TSB done to it to increase the pressure, but I have no way to tell.

Other than that it has been fine. If anybody has any input it would be appreciated.

Also I want to throw in, every time I shut the car off these codes reset until the next time they come back.

You might wanna tell us the year and which engine it is dude.....

Check your system voltage is between 13-15v running, just to rule out a bad alternator/regulator. Too high/low voltage will screw everything up, possibly effecting the PCM's functions.

...and while you are at it pull out the rear seat and check the battery connections for corrosion; test the battery for voltage - that is when the car is off and you measure voltage with a voltmeter what is it? next, if you have a load tester (most people do not) test the battery's cold cranking amps (CCAs) - many places that sell batteries (GM dealers, Sears auto centers, Goodyear and Firesotone tire stores, AutoZone, Pep Boys, etc.)do. You want to know that the battery will produce a minimum of 450 CCAs when fully charged.

Beyond that as Abaddon said you need to tell us what year/engine this is. Different years/engines matter.

Hello,

As stated above, I redid all of the ground through the car. Load test checked out ok, and the car is a 95 3.8L supercharged. I did various tests throughout and everything checks out ok (through alldata).

Voltage running from the computer is 13.9 to 14.1 volts.

brandonlong wrote:

Hello,

As stated above, I redid all of the ground through the car. Load test checked out ok, and the car is a 95 3.8L supercharged. I did various tests throughout and everything checks out ok (through alldata).

Voltage running from the computer is 13.9 to 14.1 volts.

Sounds like your thermistor (at the battery) is bad or missing & needs to be checked/replaced. The replacement cables are not cheap.

Is the battery original? Does the positive terminal have more than one line off it? Maybe you can post a pic.

Albertj

albertj wrote:

brandonlong wrote:

Hello,

As stated above, I redid all of the ground through the car. Load test checked out ok, and the car is a 95 3.8L supercharged. I did various tests throughout and everything checks out ok (through alldata).

Voltage running from the computer is 13.9 to 14.1 volts.

Sounds like your thermistor (at the battery) is bad or missing & needs to be checked/replaced. The replacement cables are not cheap.

Is the battery original? Does the positive terminal have more than one line off it? Maybe you can post a pic.

Albertj

No Battery is an Ultrapower I think, date on it is 8/10.Can I ask where you got that a bad thermistor would cause the above problems? I'm not saying your wrong I've just never heard of it...

Hi Brandon,

Send me a PM if you want me to look it over with you. I live about 15 minutes away from you.

It's very possible that you have a bad PCM, but you should check everything else first.

-Derek

brandonlong wrote:

albertj wrote:

brandonlong wrote:

Hello,

As stated above, I redid all of the ground through the car. Load test checked out ok, and the car is a 95 3.8L supercharged. I did various tests throughout and everything checks out ok (through alldata).

Voltage running from the computer is 13.9 to 14.1 volts.

Sounds like your thermistor (at the battery) is bad or missing & needs to be checked/replaced. The replacement cables are not cheap.

Is the battery original? Does the positive terminal have more than one line off it? Maybe you can post a pic.

Albertj

No Battery is an Ultrapower I think, date on it is 8/10.Can I ask where you got that a bad thermistor would cause the above problems? I'm not saying your wrong I've just never heard of it...

GM did not use this system much - but the Riv charges the battery faster if it's cool and uses a thermistor to measure battery temp. If the thermistor is missing or fried the alternator will not charge the battery properly. There was another series of posts about this but I can not find the thread, maybe the site admin will point it out?

So the reason I mentioned it is the pattern of failure you have looks a lot like the pattern that showed up in the other guy's case. That's all, really.

Oh by the way I found an Ultrapower card here:

http://www.northeastbattery.com/pdf/Ultrapower_automotive.pdf

It does not show a Group 79 battery for Ultrapower. The Riv battery has to be vented through the floor - there is a plastic vent assembly and rubber grommet in the floor it's vented to. If you do not vent the battery that way, the acid fumes will eat through the floor quickly. Very quickly. Is the Ultrapower battery you have a Group 79 (BCI number is 79) vented through pipes thru the floor of the car?

I don't understand the concern about the battery or thermistor. 13.9-14.1v is normal running voltage.

I feel for ya.

I put over $4k in new crank sensors, ignition cylinders, switches, sensors, etc. just get get the car to start everytime in the winter.


I'm still having issues but not with starting.

I had the car scanned and also have the

Throttle Position low & high codes
MAF low code

This scan was done after I replaced the TPS sensor. Even though it was a plug-in part it got me wondering if I didn't do something extra when installing it.

I had replaced the air filter after that and the engine ran like a dream, all issues gone except the engine light.

And of course something else starting going wrong so a new MAF is in my future.

But I am constantly hearing on here and online that the problems I'm having could be the MAF or something else. Now I'm hearing it could be a battery problem? I'm confused and want to make the right choices.

AA wrote:

I don't understand the concern about the battery or thermistor. 13.9-14.1v is normal running voltage.

At this point I'm suspecting prior damage. I'm also not sure of when the voltage reading was taken or how it changes over time. I don't know what the battery voltage read while car is off --although it is probably fine it is something I would check.

As far as the battery goes, I confess it's only a hunch on my part seeing that he has a recently-installed battery. Part of my hunch is driven by the following: he did not answer my comment about the battery's group number and did not confirm that it's vented properly.

I also suspect Brandon is frustrated (I would be) because with the car running one would think this was an easily-identified quirk or problem. He's done a lot and has not got improvement that seems to correspond to his effort. I really SO get that.

So at this point I don't know much else, I'll wait until more is posted and until then I'll shut up. And I hope he takes Deekster up on the offer to go have a look at it.

Albertj

Hey,

It does have a group series 79 in it, it's an AutoCraft I had the cars backwards. The vent assembly is half there... the tube that runs from left to right is there the downtube is gone.

I was up at the junkyard saturdy and found a newly remanned ECU for this so I picked it up, hey $35 bucks whatever, the codes are still there but my idles improved and the check engine light works properly now.

I am going to pull out all of the connectors between the sensors and the computer and report back, i bet it's something stupid that we are missing.

Now on the 'thermistor', is there a proper way to test it? I don't like replacing parts unless I can test them first.

-Brandon

brandonlong wrote:

Hey,

It does have a group series 79 in it, it's an AutoCraft I had the cars backwards. The vent assembly is half there... the tube that runs from left to right is there the downtube is gone.

I was up at the junkyard saturdy and found a newly remanned ECU for this so I picked it up, hey $35 bucks whatever, the codes are still there but my idles improved and the check engine light works properly now.

I am going to pull out all of the connectors between the sensors and the computer and report back, i bet it's something stupid that we are missing.

Now on the 'thermistor', is there a proper way to test it? I don't like replacing parts unless I can test them first.

-Brandon

OK on the battery. The bit with the vent tube is just to get rid of a headache (corrosion) while you are working on other stuff. Replacement vent tubing is still available for short money from GM dealers and some battery places. If a replacement ECU helped then maybe there is something to my "prior damage" idea. I really can't tell from here.

There was another thread on the thermistor, you can check the resistance with a voltmeter, I will try to find the thread for you but I'm not so great at the "search' function on here. I think this is it --

https://rivperformance.editboard.com/t8426p30-various-idiot-lights-and-intermittent-symptoms

If I remember right the cables with proper thermistor are still available but they are mad expensive. (a poster said they were not available any more). I think it depends on who you ask. If you use the guidance in that thread however you may be able to repair the cable yourself, if it needs repaired, for short money. Or to use common parts and make a thermistor jumper. Deekster posted the last note in that thread about a month ago.

By the way you may want to post a cellphone snapshot of your positive terminal and cable just in case it's already been replaced with a cable lacking the thermistor connection, someone else with a Riv who's worked on the electricals could probably tell in a flash.

I agree with not replacing parts unless you can test them. The only time I violated that rule and won, in recent memory, was when I noticed the pattern failure of my Riv's crank sensor. Without going into deep detail, the pattern is the car will not restart when fully warm and it is tough to diagnose because it simulates "key off" as far as the ECU is concerned. So it does not set a code when it dies, it just $*&#(*$& goes intermittent.

Albertj

Quote :

Now on the 'thermistor', is there a proper way to test it? I don't like replacing parts unless I can test them first.

You know the thermistor is functioning properly if voltage is in the proper range (13-15v), which yours is. I don't see any reason to suspect it.

With the new PCM installed, did all the same codes return, or only a few? Any new ones? What do you mean the SES lamp is working properly now?

I'll get back to you all on the codes friday, I haven't been driving it around.

"What do you mean the SES lamp is working properly now?"

Before these codes would set without a check engine light, now it comes on almost instantly on a warm start and intermittently on a cold start.