Mike96z...why do you lie!!?!??
Ill be @ cedar creek today, I told him to come out. Maybe you should come out too. Bring something to run.
Im riding shotgun and am a gambling man...Lets do something...
The Best V8 Stories One Small Block at Time

Its a pretty day for Yellow Belly. Nut up son.
Its a pretty day for Yellow Belly. Nut up son.
P1441 Evaporative Emissions (EVAP) system flow during non-purge
P1641 Fan Control (FC) relay 1 control circuit
P1642 Fan Control (FC) relay 2 and 3 control circuit
Yea I just made these codes up!
Guess that **** will just disappear!

Fans are a relay away from being fixed. Possibly a fuse. Ignition control, replace the coil. Evap...Gas cap away from fixing. So like I said. Nut up! You said you had money. Get it fixed and bring big ***** or stay at home and keep wishing you could beat this LS1.
Fans are a relay away from being fixed. Possibly a fuse. Ignition control, replace the coil. Evap...Gas cap away from fixing. So like I said. Nut up! You said you had money. Get it fixed and bring big ***** or stay at home and keep wishing you could beat this LS1.
Now you gotta remember how long it took us to fix my fans. Dude that **** took like 3.2 minutes so we gotta cut him a little bit of slack.
Fans are a relay away from being fixed. Possibly a fuse. Ignition control, replace the coil. Evap...Gas cap away from fixing. So like I said. Nut up! You said you had money. Get it fixed and bring big ***** or stay at home and keep wishing you could beat this LS1.
Last edited by Mike96z; Apr 15, 2007 at 03:32 PM.
The DTC 1441 is an EVAP system flow during NON_PURGE code. There is a vacuum switch between the engine intake manifold and the evap purge solenoid. When the solenoid is commanded open, the switch opens to let the PCM know the vacuum is flowing. In your case, the solenoid is not commanded open but the switch is still open when it should be closed.
The DTC 1641 is for one of the cooling fan relays and the 1642 is for the other 2 fan relays.
The fans are turned on and off by the PCM. It will provide a ground to the relay when it wants a fan to turn on. This completes the circuit to the relay coil causing the relay to pull in and thus turns on the fan. There is always 12 volts going to the relay coil but it only gets ground (completing the circuit) when the PCM wants the fan on.
In the case of the 1641 or the 1642, the PCM has detected a voltage other than battery voltage on the wire that turns on the relay. It signals by throwing a code.
To explain further, many of the control signals from the PCM are also monitored to be sure they are at the correct potential at times they are not being used. So in the case of the relay control lines, the control line from the PCM to the fan control relays should hover near battery voltage until the PCM pulls it to ground completing the circuit to the relay and thus turning on the relay. Until it pulls the control line to ground, it monitors the line to see if it is at battery voltage.
What you are concerned with here are the dark blue and dark green wires going to the red PCM connector on pins 10 and 11. There should be 12 volts there all the time. If there is no power there, check the 25amp fuse #7 under hood. If it's low voltage but not zero, start by checking the voltage at the battery.
Incidentally, there is one common item that might explain all your symptoms. If the 12 volts supplied by the battery and the alternator were either lower than threshold OR it had too much AC voltage on it. It could cause random PCM failures of varying types. THEREFORE it is a good idea to eliminate the charging system as the cause of weird electrical failures BEFORE going on a wild goose chase.
To do that is simple. Start the vehicle and measure the DC voltage across the battery terminals. It should be around 14 volts. Now to check AC leakage from the alternator, set the meter to AC and measure from the negative battery terminal to the large output post of the alternator. It should NOT be above 0.03 volts AC. If it is above that, the diodes inside the alternator are defective and they are allowing too much AC voltage to get on the 12 volt line. Too much AC can, (notice I said can) make the PCM do strange things.







