The Diesel Garage banner

1 - 5 of 5 Posts

·
Junior Member
Joined
·
123 Posts
Discussion Starter #1
Hello again. My 2006 f250 has recently developed a weird issue, it will not show what codes I have. I know I have 2 bad glowplugs. I have a scangauge and it still shows all the info from the x-gauges, just wont show me any codes (says there are 3 but wont show me). I tried another local shop that had a scanner and it did the same thing. Any suggestions on how or what to check and look for? Thanks again Mike
 

·
Stuck in Commiefornia...
Joined
·
1,296 Posts
I've only seen something like this when the tune from a programmer doesn't match the strategy. If you have a programmer on the truck, try returning the truck to stock. Then scan the truck. Now, this may clear the codes, but if it's truly bad glow plugs, the code should return after a couple warmups.
 
  • Like
Reactions: MT Pockets

·
Senior Member
Joined
·
3,051 Posts
MT...it's possible 2 of the 3 codes are your glow plug faults...you can test the glow plugs from the harness connector at the "glow plug control module" by "unplugging the connector-s for the glow plugs" and ohming each of the 8 glow plug connector pins to ground with the "engine cold"...each of the 8 glow plug pins should read around .5 to 1.2 ohms max, anything higher and it's a bad glow plug. Also...sometimes, glow plugs will ohm out fine but fail only during the 12v power cycle when they are activated...but usually faulty glow plugs will show up during a cold engine ohm test...if you test them warm it is not a reliable test as the resistance inside the glow plug changes when they are hot-warm.

As far as not being able to read codes, could also be a fault in your OBDII connector or a bad fuse somewhere. Check to make sure none of the OBDII connector pins on the trucks side are not pushed back in the connector or are possibly loose, and check the fuse chart to see if any fuses are related to diagnostics or the OBDII connector.

Harry
 
  • Like
Reactions: MT Pockets

·
Junior Member
Joined
·
123 Posts
Discussion Starter #4
The truck is not tuned. My scangauge was working fine until I left the radio playing overnight( forgot it for a while). Batteries were low but not dead, it still started and charged. The pins all look fine at the port and couldn't find any bad fuses. I will double check everything again tomorrow. Thanks
 

·
Stuck in Commiefornia...
Joined
·
1,296 Posts
Try disconnecting both grounds from the batteries. While they are disconnected, enter the truck, turn the key to all positions, cycle the headlights, tap the brake pedal, cycle the power to the radio and heater, any accessories, upfitter switched devices, brake controller, etc. The idea is to remove all traces of electrical capacitance in the truck. Check all the fuses under the hood and in the dash. Make sure the batteries are at a full charge before you reconnect them. This should reset the KAM (Keep Alive Memory) in the computer and clear any communication issues in the Can Bus communications system of the truck, used by the radio, the instrument cluster and the PCM. If the problem persists, you may need to visit the stealership for programming.
 
  • Like
Reactions: MT Pockets
1 - 5 of 5 Posts
Top