That was intended as a compliment in case you happen to stumble on this thread, Bill. I've seen a lot of respect for your electrical prowess.

The quick of it: '99 FRC, car had no electrical issues last fall the last time it ran. Over the winter, removed engine, rebuilt engine, reinstalled engine. During engine rebuild, PCM was reprogrammed by Speed Inc in Schaumburg, basically a mail order tune based on all of the motor upgrades.

Now the issues:

1) Starter was incorrectly wired with a ground wire added to the starter solenoid output, so when i turned key to run for first time, obviously it shorted to ground, and had the associated tick-tick-tick-tick sound that you might hear when your battery is low.
2) The reverse lockout solenoid is cycling rapidly, maybe 8-10 cycles per second. As memory serves, this was happening (I think) before the first short was introduced in #1 above. It's almost like it's getting a square wave signal from the PCM.
3) When I key-on to run, I get the following issues

Car doesn't start (it ran briefly for 10-15 seconds after we got starter wired correctly and were going through process of making sure oil was getting to all parts of engine.
o Sound is like it's out of gas, as in there is the occasional fire once every 2-3 seconds. I know it's not out of gas, plenty of fuel at the rail, i can smell the gas, etc.
Gauges:
o All gauges run through needle-check at key-on as normal, after that:
+ Fuel gauge reads empty (I know there's fuel in the car)
+ Coolant gauge is pegged at H
+ Oil pressure gauge pegged at 0
DIC messages:
o Reduced Engine Power
o Low Coolant (this is OK, there's no coolant in the car yet)
o Service Traction System
o Service Vehicle Soon
o Service Active Handling
o Low fuel
o Oil Pressure and Coolant Temp in the DIC show "Coolant Temp: *F............. i.e. it's blank, no number. Oil temp reads out normally at 73* / ambient temp.
DTC's that show up:
o PCM
+ P1638 HC - I"m guessing that this is tied to the starter short circuit, and the alternator (regulator) got toasted
o TCS
+ U1255 HC
o BCM
+ B2587 H
+ B2592 H
+ U1255 HC
o SDM
-U1000 HC
-U1016 HC
o RFA U1000 HC
o IPC, SCM and Radio - no codes
Reverse lockout solenoid cycles rapdly


I've cleaned/checked all under hood grounds that I could find (1 behind each headlight on frame rails, 1 splice pack behind battery on frame rail, 1 engine ground to negative battery cable, 1 ground stud on frame rail next to battery) as well as splice packs in each of the footwells. All splice packs were clean, no corrosion. I've checked all fuses in the in-car box and the under hood box. Removed the connector cap from the 4-wire STAR / bus in the passenger footwell per Bill's post to another question about helping to isolate the issue. It wreaks of a comm issue, but interesting that the PCM doesn't show any codes for that.

Any folks like Bill or otherwise who can help? The car's electrical system is going nuts, and I"m about to as well. Thanks guys.

 

Did you reconnect the black ground wire/s on the passengers and drivers side of the block????????????? G-106 near the starter an G-105 near the oil filter housing

If NOT,, GET HOT!

 

Yep!! the driver side braided wire is connected to frame rail, the passenger side insulated cable appears to be the one coming from battery box.

 

G-107 on the back side of the drivers head connected??

 

Yep, two ground wires going into a ring terminal on back face of driver's side head.

Based on your description, I was thinking that was G-114? It provides ground to the ignition coils?

 

Bill is the Master, but I'll chime in here, because the OP's response is not complete. There are two connections at G106(above starter), NOT just the battery cable. The smaller wire that connects to G106 provides the grounds for the PCM.

Also, you only mention the braided wire on the left side of the block(G105). There are two connections there as well. The other connection provides a ground for SP122, which in turn provides grounds for the oil level sensor, O2's, and the fuel pump relay.

 

I've never seen a ground location G-114.......Bill is correct.


http://forums.corvetteforum.com/c5-t...e-grounds.html

 

I"d just been going off of what I thought was an FSM's electrical page... 57 pages of it to be exact. Thankfully the majority of number references are correct, including splice packs and their associated components.

Due to the headers, it was tough to get a hand down to G106 above starter but in fact both grounds are there. Checked the driver side, too, and that also has both grounds in place.

 

That P1638 code seems to be related to the alternator so I'm wondering if he toasted the fuseable link.

 

DTC P1638
Circuit Description
The PCM 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 PCM uses the PWM signal input to determine the generator load on the engine. This allows the PCM to adjust the idle speed to compensate for high electrical loads.

The PCM 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 PCM 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 PCM monitors the PWM signal using a key ON test and a RUN test. During the tests, if the PCM detects an out of range PWM signal, DTC P1638 will set. When the DTC sets, the PCM will send a class 2 serial data message to the IPC to illuminate the Charge System Fault message.

Conditions for Running the DTC
Key ON Test
No generator, CKP sensors, or 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 3000 RPM.
Conditions for Setting the DTC
During the key ON test, the PCM detects a PWM signal greater than 65 percent for at least 5 seconds. OR
During the RUN test, the PCM detects a PWM signal less than 5 percent for at least 15 seconds.
Action Taken When the DTC Sets
The PCM will not illuminate the Malfunction Indicator Lamp (MIL)
The PCM 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.
Step
Action
Yes
No

Schematic Reference: Starting and Charging Schematics

1
Did you perform the Engine Electrical Diagnostic System Check?
Go to Step 2
Go to Diagnostic System Check - Engine Electrical

2
Install a scan tool.
Start the engine.
With a scant tool, monitor the DTC information for DTC P1638 in Engine Controls.
Does the scan tool indicate that DTC P1638 has passed?
Go to Testing for Intermittent and Poor Connections in Wiring Systems
Go to Step 3

3
Turn ON the ignition, leaving the engine OFF.
Disconnect the generator harness connector.
Connect a test lamp to battery positive voltage and repeatedly probe the generator field duty cycle signal circuit in the harness connector while monitoring the GEN F-Terminal Signal on the scan tool.
Is the Generator PWM display affected?
Go to Step 5
Go to Step 4

4
Test the generator field duty cycle signal circuit for a short or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
Go to Step 8
Go to Step 6

5
Inspect for poor connections at the harness connector of the generator. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?
Go to Step 8
Go to Charging System Test

6
Inspect for poor connections at the harness connector of the PCM. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?
Go to Step 8
Go to Step 7

7

Important
The replacement PCM must be programmed. Refer to Powertrain Control Module (PCM) Programming in Engine Controls 5.7L.


Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement in Engine Controls 5.7L.

Did you complete the repair?
Go to Step 8
--

8
Review and record the scan tool Fail Records data.
Clear any DTCs.
Operate the vehicle within the Fail Records conditions as noted.
Using a scan tool, monitor the Specific DTC info for this DTC.
Does the scan tool indicate that this DTC failed this ignition?
Go to Step 2
System OK



--------------------------------------------------------------------------------
Document ID# 726036
2002 Chevrolet Corvette

 

With all the U series DTCs you have and comms issues, its most likely caused by a power issue to those modules. Check all your fuses and make sure that there not blown. You also meed to make sure tha you have power to those fuses. REMEMBER! Some fuses are hot at all times and some are only powered when the curcuit is ON. EXAMPLE: The IGNITION SWITCH powered fuses.

Do you have a service manual and a meter??




BC

 

New PCM and I'm good to go!! Thanks to Bill and Lucky for all of the help. Seriously... this forum has been a great help!

 

I always feel good when I see issues fixed like this. They can be so traumatic when you are going through them. Gotta love this forum.