Jump to content

Recommended Posts

Posted

I'm trying to work through this code. MIL stays on all the time. No other codes. Did a 'check' of the IPC and can turn on all lights in the IPC and turn them off with my Launch scan tool. Once exiting the test, the MIL is still on. I used a flow-chart for a C3500 as I can't find one for the 4500 and the MIL is supposed to be turned on via a signal on pin 46 of ECM Connector #2. Wiring of this connector looks just like the wiring diagram for the 3500. When removing the C2 ECM connector the light says on in the dash. When I unplug the C1 connector the light will go out. So, the MIL is being turned on by something in connector #1. I was wondering if anyone on here has any ideas. Thank you,

Posted

I would disassemble the IPC and look for shorts. Some careful probing with a multimeter ought to be able to track it down. 

 

I suspect the C1 connector has an 'always on' circuit in it that is back feeding the MIL circuit and thus throwing the code.

 

I don't have a diagram to refer to to try narrowing it down further.

Posted
2 minutes ago, asilverblazer said:

I would disassemble the IPC and look for shorts. Some careful probing with a multimeter ought to be able to track it down. 

 

I suspect the C1 connector has an 'always on' circuit in it that is back feeding the MIL circuit and thus throwing the code.

 

I don't have a diagram to refer to to try narrowing it down further.

See this link...

 

https://www.gmupfitter.com/wp-content/uploads/2021/05/2004_MD_CSeries.pdf

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Latest Articles

  • Posts

    • Mediocre, how much did they lose on the poorly conceived EV strategy?   I wonder how much the stock price is being 'inflated' by all the buy-backs?   Cadillac literally looks like a brand without a rudder, no clear goals or product direction - performance or luxury? I guess performance because we can throw a small block in whatever we can and call it a day. Certainly not luxury when a Denali or High Country is reasonably cross shoppable. The Celestiq - no way - no vehicle can command quarter million prices when something wearing the same badge is on the buy here pay here lot across town.   Notice the 'base' Escalade doesn't even come with the 'leather-appointed' seating surfaces.   Hummer EV - fail Silverado EV - fail Sierra EV - fail Bolt/Volt EV (The most successful EV cancelled, restarted, cancelled, whatever its current status it)   Hybrids - none Sedans - none Medium duty - not anymore Minivan - none Coupe - none Convertible - none CUVs - 20+/-   6.2 Recall that landed squarely on the GMs highest seller - and specifically the fattest margin higher trims of the Yukon, Escalade, et. al. The most critical product line they fumbled big time. In the Escalade segment, are those buyers forgiving GM for a bad engine and patiently waiting for the fixes and dealing with the headaches? Nope, they dump them and go straight to the other premium brands.   In the ENTIRE GM portfolio how many aspirational vehicles are there? Corvette, Escalade (quickly being superseded by the obvious better value Denali)...   I posted somewhere else... what if Cadillac left the luxury game and became a performance brand similar to AMG or (gasp) Ferrari? Cut all the entry-level and base models from their line up and focus on the V-series or Blackwing or whatever they call it now. Of course, those would have the pre-requisite luxury and technology as standard equipment. This opens the floor for Buick to step in/up as the luxury brand (like they are in China), no 'performance pretenses' get rid of the 'entry-level' models with equally 'entry-level' power trains and become the Maybach to Cadillacs AMG. With those two brands effectively out of the way Chevrolet, the 'entry-level' brand has the floor to itself and GMC can take over as 'professional grade'.    Now each brand has a focus, no in-fighting, clear direction, and customer targets.   Just need to sneakily slide Corvette into the Cadillac brand and dump the vestigial script writing.
    • I can't get enthusiastic about the 1.5T (or the 1.3 or the 1.2), I won't drive a CVT. But the stupid things sell in volume.
    • There is a big difference in motorcycles and vehicles - nobody needs a motorcycle, they WANT one. That WANT is the most powerful force to drive price upwards.   I've hated every iteration of the Equinox, a prime example of GM laziness. It excelled at absolutely nothing, barely competitive by every metric. At least the latest generation looks decent.    I want to like the Buick Envista, but that pitiful engine plus FWD only is a BIG NO for me, I don't care how good it looks.
    • For as much hate as Ms. Barra receives on here, she sure is a shrewd businesswoman....
    • Love my new 2026 truck - even as a basic WT it's comfy, rides nicely, etc.   Encouraged by the 100K powertrain warranty.   2nd GM I've ever owned (1st was a 2000SLE with Vortec V6 - loved that truck.) Small question - maybe I'm missing it in the manual? - but I seem to need to press the unlock button first, in order to open driver's door.  (Don't care as much about passenger door.) RKIs: is there any mod/setting change, etc such that when I merely pull the door handle it just unlocks + opens? I have minor concerns about ability to exit regardless of electrical performance. (I'm a bit limited agility w/osteoporosis from hyperparathyroidism - big guy, age 62, range of movement etc issues.) Thanks, Bill San Jose CA
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...