TucsonDiesel

Just finished replacing the VP44. All hooked up, system has been bled.

Engine runs fine. Disconnected the neg battery terminals for 1/2 hour.

The Check Engine light is still on. I hooked up the scan tool, and there isnt any codes.

What did I miss?

Thanks

Mike

dozer12216

Have a scanner erase codes.

TucsonDiesel

I did. Hooked the scanner up, and forced it to clear the codes. There are no codes being reported by the scan tool, yet the Check Engine light is still on.

dkenny

what scan tool? if the CEL is on there is a code..
maybe you need a better scanner? try the free one at advance auto parts

-dkenny

TucsonDiesel

More info

My scan tool still gets some codes intermittently, but they are the same codes that were read out when the VP44 died a hard death

P1688, P0251, P0252, P0253

Exact same codes at time of death

But, the LP works good (replaced), and the VP44 is putting out good pressure, lots more power than before.

I do have an old scan tool, going to AutoZone after work to have them hook up and clear codes, and reset MIL light.

I did remove the neg side of each battery for over 1/2 hour, this should have cleared everything, but didnt, thats why I am corn fused.

Mike

Joe Diesel

what year rig? did you try to cycle the key?

TucsonDiesel

1999 120K miles

Any recommendation on which scan tool to buy?

Anybody still have codes present after new VP44 and LP?

ted_pulliam

On my 01.5, I found out that disconnecting both + and - connections from both batteries for 2 hours does nothing to clear the codes. I recently replaced my head gasket and incurred an 0122 (apps voltage to low due to my having left the apps sensor disconnected) and 0217 (engine overheated) - due to air bubble in cooling system. Both of these codes are still present after disconnecting and reconnecting the battery for hours on end. I asked AutoZone to scan and clear the codes and they wouldn't. The Autozone guy ran the scantool to find the codes but said he might get fired if he cleared them!

I am sure the codes on my truck are not being re-added, since my apps sensor is and has been connected since I first got the code, and since the truck has not run past 190 degrees since these codes were stored. The computer must have its own power source.

TucsonDiesel

Or they are latched in flash memory that doesnt need power. If the Autozone guy wont clear them, I will buy their scan tool for $80, and clear them myself in their parking lot.

Thanks for the feedback.

BTW, the replace/install went fairly straight forward via the Diesel Dan videos, but their was some detail that the manual and the videos couldnt resolve.

Video says that the gear should remain loose while tightening the nuts, and the manual says to put the main lock washer and nut on during the tightening process. All of which cinches the keyway to the slot, locking the gear in place.

Manual says that the flange should be flat against the block before tightening nuts, but I had about 1/8th of inch gap before tightening the nuts, and the keyway was dead on in the slot. That is normal because remember, you needed that gear puller to take they gear off the keyway. Little stuff.

manual doesnt say anything about using the scan tool to clear codes, but that might be a normal step at the dealership.

TucsonDiesel

Ok, went to Autozone, they loaned me their scan tool. Erased the codes and the Check Engine lite went away. Codes must be stored in computer memory, unaffected by removing battery power.