Service Electrical System 2005 Corvette, continuing after 2 years
 

I'm lost,... praying someone on here has a solution to this problem that has been ongoing for the last 2 years. I have just lost my second summer and I am starting to get disgusted with this car. To make a long story short my previous tuner installed a ECM out of a GTO after my first one failed. I am told by the current tuner that the drivers had an issue as a result of the incorrect pcm and killed the second one. This took almost a year to diagnose as the car would run fine from time to time, then start missing for no reason. I had GM install a new ECM and had a friend do a very basic tune. Took the car out for a ride in the spring of this year and I am getting a error on the dic for service charging system now. Its an 05 C6 with heads, cam, and a roots blower. It has a standalone fuel system and a DC Power engineering alternator. I just sent the alternator back to DC to have them check it and i'm told its OK. I checked all the grounds in the vehicle and they are all clean. I am running Denso IT22 plugs. Tomorrow I will switch them out to TR6's. My tuner doesn't want to tune the vehicle till this is resolved. The current tune sucks, and I am unable to really drive the car the way I would like. I need some ideas. I'm out of f**king ideas....

Dan

In my haste to unload my problems on this thread I posted "service electrical system." that was the original issue which the new ECM fixed. I'm Currently facing a service charging system issue... this is what I am trying to fix

Is it setting an actual B, C, P, or U code? If so what is the number?

Didn't have any codes a week ago. Just checked again after you posted. I have a code P0622 and no MIL. Wierd. At least I have something to work off of. Anybody see this code before?

What I don't see in all of this, is any mention of whether
the charging voltage is right or wrong. At the battery,
at the PCM (whatever it is today), and at the block as
ground to both of those. Maybe it's just a dumb busted
/ loose / crusty ground strap or something. Old school
voltmeter, poke around, look for anything that doesn't
agree point to point to point.

Also see whether this all pops at any particular operating
point - idle, high RPM, rainy days, whatever. Seems like
any clue would help now.

DTC P0622

CIRCUIT DESCRIPTION
The engine control module (ECM) uses the generator field duty cycle signal circuit to monitor the duty cycle of the generator. The generator field duty cycle signal circuit connects to the high side of the field winding in the generator. A pulse width modulated (PWM) high side driver in the voltage regulator turns the field winding ON and OFF. The ECM uses the PWM signal input to determine the generator load on the engine. This allows the ECM to adjust the idle speed to compensate for high electrical loads.

The ECM monitors the state of the generator field duty cycle signal circuit. When the key is in the RUN position and the engine is OFF, the ECM should detect a duty cycle near 0 percent. However, when the engine is running, the duty cycle should be between 5 percent and 100 percent. The ECM monitors the PWM signal using a key ON test and a RUN test. During the tests, if the ECM detects an out of range PWM signal, DTC P0622 will set. When the DTC sets, the ECM will send a serial data message to the drivers information center (DIC) to display a warning message.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC: DTC P0622 Generator F-Terminal Circuit

CONDITIONS FOR RUNNING THE DTC

Key ON Test

No generator, crankshaft position (CKP) sensors, or camshaft position (CMP) sensor DTCs are set.
The key is in the RUN position.
The engine is not running.

Run Test

No generator, CKP sensors, or CMP sensor DTCs are set.
The engine is less than 3,000 RPM .

CONDITIONS FOR SETTING THE DTC

During the key ON test, the ECM detects a PWM signal greater than 65 percent for at least 5 seconds .
During the RUN test, the ECM detects a PWM signal less than 5 percent for at least 15 seconds .

ACTION TAKEN WHEN THE DTC SETS

The ECM will not illuminate the malfunction indicator lamp (MIL).
The ECM will store the conditions present when the DTC set as Fail Records data only.

CONDITIONS FOR CLEARING THE MIL/DTC

The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using the scan tool Clear DTC Information function.

.....

2xLS1, Thanks for all your help! I have amazing news. I found the problem. After reading over the documents above I decided to trace the F Terminal. At first everything looked fine. After an hour I was leaning over the car pulling my hair out of my head when I noticed that a tiny piece of one of the pins in the connect was sticking out the bottom and didn't look the same as all the rest. When I took apart the connector I realized that the pin was loose and that the wire looked fine from the outside but as I put the connect together the wire was actually moving out of the housing. I pulled the wire forward through the broken connector and put the pin directly into the other side so it was plugged in. Then slid the rest of the connector together. When I started the car 2 years of issues were gone! I can't thank you enough. Sometimes when your caught up in not being able to fix something you need an outside prospective. I can't thank you enough for giving it to me!

Dan

I just handed you the tool. You did the work.