Hello good night, I’m a new Hummer owner and this code/issue has been driving me crazy! My hummer drives/runs just perfect, no issues at all, I connected the obd because the engine light will come on all of a sudden and then would go off, first it would tell me engine misfires, o2 sensors and MAF , I’ve replaced everything, everything is brand new, GM parts! I drove 250 miles this past weekend and here and there the engine light would come on , I connected the scanner again and now the code that I have is p0650!
can somebody please tell me what else I need to do/fix so I can get rid of it?
thank you

 

Malfunction Indicator Lamp Circuit Malfunction.
Engine started, engine running, system voltage over 10.0v, and the PCM detected the Actual and Commanded state of the Malfunction Indicator Lamp (MIL) driver did not match.

• MIL control circuit is open or shorted to ground
• MIL control circuit is shorted to system power
• MIL control power circuit is open in the Instrument Cluster
• MIL (the lamp) is damaged or has failed
• Instrument Cluster or the PCM has failed

 

Thank you so much, could you tell me where should I start checking this out?

 

Adding to what hummerz has already posted.

The MIL is what many refer to as the "Engine Warning Light" it's interesting that the GM Service Information starts by saying :-

The malfunction indicator lamp (MIL) is located on the instrument panel cluster (IPC). The MIL informs the driver that an emission system fault has occurred and that the engine control system requires service. The control module monitors the MIL control circuit for conditions that are incorrect for the commanded state of the MIL. For example, a failure condition exists if the control module detects low voltage when the MIL is commanded OFF, or high voltage when the MIL is commanded ON. If the control module detects an improper voltage on the MIL control circuit, DTC P0650 will set.

Conditions for Running the DTC
• The engine speed is more than 400 RPM.
• The ignition voltage is between 6-18 volts.
• DTC P0650 runs continuously when the above conditions are met.

Note the second sentence refers to an "emission system fault" which is interesting since you've had "engine misfires, o2 sensors and MAF" in the past.

By changing "everything" do you mean O2 Sensors and MAF? (what about CATS?)
For a little history, what were the other previous diagnostic codes?

However there seems to be no reference as to exactly what an emission system fault is, it could be a red-herring but definitely cited under the DTC description.

It's seems the Instrument Panel Cluster has some intelligence built-in around the Engine Warning Light (MIL) which may be for security and to protect against tampering e.g. a defective lamp or lamp removal. The IPC Connector Pin-A1 (BRN/WHT) connects directly to the Powertrain Control Module (PCM) Pin 46, the PCM generates the MIL condition and the IPC logic confirms the lamp's activity back to the BCU (probably)

As your lamp is working it probably isn't defective (could be intermittent) it could be the IPC logic that's defective, however its odd that it follows previous error codes.

Depending on your OBD tool, I'd be tempted to get your H2 scanned by a Tech2 which may provide more information and I believe can test the MIL

P0650 seems to be a rare condition, I assume the MIL come on and goes off when the ignition is turned on.

Also I've heard that strange IPC activity being cured by disconnecting the battery for a few minutes, also heard that it can be battery condition or voltage related.

What year Hummer do you have?

 

My hummer is an 04 , and I’ve replaced spark plugs, spark plug wires, ignition coils, MAF , o2 sensors, PCV valve, air filter, should I just replace headers and CATS or do you think is the instrument cluster?

 

Sure, if you got bank, keep throwing parts at it.

 

Save some dough and check / inspect ipc/dic fuse/contacts in the uhfb.

 

It could be an intermittent 10A fuse as hummerz suggests, it's easy to check both IPC/DIC and" IGN E" (fuses 19 & 11) or just replace them.

Any snippets of info could be useful here, previous DTCs (as mentioned) strange activity with the IPC, anything else electrical. What are the engine load conditions when the MIL is set, e.g. travelling up hill, vibration, engine load, etc.?

Any electrical after market stuff, wiring mods?

Is your battery good? Terminals good?

CAT's are expensive, so it's better to track down the fault 1st, as I said a TECH2 would help, unless that's what you have.

 

Thank you so much for this answer! The only aftermarket stuff is the radio that the previous owner installed, also had a light bar on the roof but I took it off! As for the battery it’s brand new! I don’t know if it has any interest but I noticed that my Obd port was working so I replaced the cigarette lighter fuse, it last me 2-3 days and blows out again!

 

thats not normal. maybe the radio install is sub par causing fuses to blow. have you done any work on the drivers side exhaust manifold or the power steering pump? there is a ground there that feeds the coils and a couple other things located on the engine block in that area.