4x4 doesn't engage, P0171 and P0174 when switch to 4LO... IWE Solenoid?
01-25-2017, 11:55 PM
#1
4x4 doesn't engage, P0171 and P0174 when switch to 4LO... IWE Solenoid?
Hi All,
An interesting problem I am having, but feel someone on here may have had the issue before.
Just recently replaced the driver side 4wd actuator. When testing the system to see if it was working, I noticed that in 2wd everything seemed to be in order (wheel spun without the half shaft, no grinding noises on test drive, seemed good to go).
However, when I switched to 4hi, the dash light "4HI" would come on but the wheel still spun freely without the half shaft. When the truck was off, the wheel and half shaft spun together as they should when vacuum is released from the actuator. When I switched to 4lo, the dash light did not come on and the check engine light came on. Pulling codes revealed P0171 and P0174.
Could these codes be caused by a bad solenoid? Is the solenoid not switching the vacuum off and that's my issue? Are there other possibilities?
Thanks all in advance!
An interesting problem I am having, but feel someone on here may have had the issue before.
Just recently replaced the driver side 4wd actuator. When testing the system to see if it was working, I noticed that in 2wd everything seemed to be in order (wheel spun without the half shaft, no grinding noises on test drive, seemed good to go).
However, when I switched to 4hi, the dash light "4HI" would come on but the wheel still spun freely without the half shaft. When the truck was off, the wheel and half shaft spun together as they should when vacuum is released from the actuator. When I switched to 4lo, the dash light did not come on and the check engine light came on. Pulling codes revealed P0171 and P0174.
Could these codes be caused by a bad solenoid? Is the solenoid not switching the vacuum off and that's my issue? Are there other possibilities?
Thanks all in advance!
01-26-2017, 05:34 AM
#2
Mark
iTrader: (1)
I would replace the IWE solenoid on the firewall if you have not replaced it yet.. what year truck we working on ?. not sure where the lean codes are coming from.. could be a vacuum issue. You may want to inspect the vacuume box and all lines.
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nddragon01 (01-26-2017)
01-26-2017, 12:39 PM
#3
Thanks techrep, can always count on you for some good advice.
Some clarification and updates:
Truck is a 2006 FX4 SuperCrew, the solenoid has been changed before to the new style back in 2008, but who's to say it hasn't died again... I have another on order to try tomorrow and return if not the problem.
I forgot 4LO only engages when in neutral with foot on brake...my bad. 4LO sounded like it's working this morning. I only hear one loud "thunk" like it's engaging, should there be two loud "thunks", one for each side? It also "un-thunks" once when switching back to 4HI or 2HI.
Actually spinning the hubs, I only checked the truck driver side since that was the side I replaced the actuator. While truck was off the hub spun with the axle shaft, while truck was on and in park and in 2wd the hub spun without the axle shaft (so I don't think there is a vacuum problem?), while truck was on and in park and in 4wd the hub still spun without the axle... does the truck need to be in neutral in order to spin the wheel to see it engage with the axle shaft?
Driving around town and to work today I did not hear any grinding, so I'm thinking my issue is the vacuum is not releasing, which is what led me to believe it is the solenoid again.
I'm planning to test more hopefully tonight, spinning both hubs one at a time, truck in 4HI and neutral, then truck in 4LO and neutral. Friday night testing will be with the new solenoid installed.
As far as the codes, they may be coincidental, but so not to ignore them, where exactly is the vacuum box located? Is that a short term for a specific part?
Thanks again!
Some clarification and updates:
Truck is a 2006 FX4 SuperCrew, the solenoid has been changed before to the new style back in 2008, but who's to say it hasn't died again... I have another on order to try tomorrow and return if not the problem.
I forgot 4LO only engages when in neutral with foot on brake...my bad. 4LO sounded like it's working this morning. I only hear one loud "thunk" like it's engaging, should there be two loud "thunks", one for each side? It also "un-thunks" once when switching back to 4HI or 2HI.
Actually spinning the hubs, I only checked the truck driver side since that was the side I replaced the actuator. While truck was off the hub spun with the axle shaft, while truck was on and in park and in 2wd the hub spun without the axle shaft (so I don't think there is a vacuum problem?), while truck was on and in park and in 4wd the hub still spun without the axle... does the truck need to be in neutral in order to spin the wheel to see it engage with the axle shaft?
Driving around town and to work today I did not hear any grinding, so I'm thinking my issue is the vacuum is not releasing, which is what led me to believe it is the solenoid again.
I'm planning to test more hopefully tonight, spinning both hubs one at a time, truck in 4HI and neutral, then truck in 4LO and neutral. Friday night testing will be with the new solenoid installed.
As far as the codes, they may be coincidental, but so not to ignore them, where exactly is the vacuum box located? Is that a short term for a specific part?
Thanks again!
Last edited by nddragon01; 01-26-2017 at 12:42 PM.
01-27-2017, 06:08 AM
#4
Mark
iTrader: (1)
Go barrow a vacuum pump from your local auto parts store and test the system properly.
With the engine running this will provide vacuum to the wheel ends and should not spin your CV shafts unless you have selected 4WD and the solenoid has vented the IWE's. IWE's also are spring loaded to aid in engagement when vacuum is vented. A vacuum pump test will bring all this to light without having to toss parts at the problem.
With the engine running this will provide vacuum to the wheel ends and should not spin your CV shafts unless you have selected 4WD and the solenoid has vented the IWE's. IWE's also are spring loaded to aid in engagement when vacuum is vented. A vacuum pump test will bring all this to light without having to toss parts at the problem.
