w.tx iceman

07 5.9 code 629, a friend has this and truck will not fire up. It is a fuel pump circuit voltage low code from what I have read but you can hear the lift pump running. Thanks for anyones help

doorguy

I would open the drain on the filter housing drain the fuel out, close it then bump the starter a couple times. Then crack open the drain and see if there is fuel there. If there is lift pump is working if not dead lift pump. That is all the help I can be you will have to wait for someone else to chime in.

BigIron70

Are you sure this is the code? P0629-HIGH VOLTAGE DETECTED AT THE FUEL LIFT PUMP
Possible causes are:
DAMAGED WIRING HARNESS
LIFT PUMP DRIVER CIRCUIT SHORTED TO GROUND
ECM
TIPM
I have had several TIPM's go bad and will cause no start condition. Loose connections at the battery terminals will cause these to go out.
The Totally Integrated Power Module (2)(TIPM) is a combination unit that performs the functions of the Power Distribution Center (PDC) and the Front Control Module. The TIPM is a printed circuit board based module that contains fuses, internal relays and a microprocessor that performs the functions previously executed by the FCM. The TIPM (2) is located in the engine compartment, next to the battery (1) and connects directly to the B+ cable (5) via a stud located on top of the unit. The ground connection is via electrical connectors. The TIPM provides the primary means of voltage distribution and protection for the entire vehicle.

The molded plastic TIPM housing includes a base and cover. The TIPM cover is easily opened or removed for service and has a fuse and relay layout map integral to the inside surface of the cover. The TIPM housing base and cover are secured in place via mounting tabs. The mounting tabs secure the TIPM (2) to the battery tray mounting bracket (3).
Should be covered under your warranty, call your dealer.

Bob Wagner

good post BigIron

w.tx iceman

thanks for the help, I will let him know the bad news

BigIron70

You may want to try this but be advised it will clear any stored codes. Wireless control module (WCM) may also cause a no start or no crank condition. If the truck was built on or before (November 30, 2007) (MDH 1130XX). To reset or (unlock) disconnect battery negative cables and waiting 30 sec then reconnecting cables. Refer to tsb:08-007-08. Dry or cold weather may cause a electrostatic discharge (ESD) from ignition key into the wireless control module (WCM) causing the WCM to electronically lockup. If the WCM is electronically locked up, the StarScan will display the WCM as being "off bus" if you have vehicle towed to dealership for repairs.