New PMD on 2003 Hummer H1 and now Check Engine Light? Need advice please

[VegasHummer]

I just got my 2003 wagon back from being serviced. They installed a remote PMD and cooler on top of my battery mount along with other normal service items. The PMD is the only real "change"

I got about 50 miles and then a red check engine light came on. I had just turned the AC on and it was not blowing out the dash vents, it was coming out of the defrost vents and then suddenly changed to the dash vents. I have read somewhere that this could be indicative of a vacuum issue. Maybe a line was knocked loose while they were working on it? It has very little power suddenly, feels like there is no boost.

When I got home I hooked up my new OBDII scanner and opened the Torque app and found these two engine codes:

P0236 - Powertrain Turbo/Supercharger BoostSensor "A" Circuit Range/Performance

P0251 - Powertrain Injection Pump Fuel Metering Control "A" (Cam/rotor/injector)

These codes make me think it is related to the new PMD. I tracked the cable back towards the engine and it seems to be plugged in down where it will be hard to access. Does anyone have a video showing how to reconnect the original PMD so I can get back on the road?

Any other suggestions of what it could be?

Thanks!

Bill

 

[MrMarty51]

Welcome to the forum VH.
Does this unit have a vacuum pump ? If so, check how many inches of vacuum it is creating.

 

[Wreckinball67]

Did the resistor come over from the last PMD? Disconnect the PMD from the harness and look into the female end. There should be a tiny circuit board looking piece bottomed in the female side of the harness. Note: This also could be at done at the at the other end of the harness since you now have an extension to the original harness. Sometimes guys put the resistor in the connection nearest the injection pump so you don't have to mess with it in the future if you swap out the PMD again.

 

[denata]

From the vacuum pump to the turbine control valve, there is a thin plastic tube, sometimes it cracks or breaks.
Part# 5744652

 

[JMJNet]

Did you connect the extension cable correctly?
There are orientation on those cable but it is not clear on the extension connector.

Where did you buy the cable and PMD from?
The tricky one is the extension cable and some Dorman PMD have been known to be DOA or now working properly even when new.

 

[MrMarty51]

My truck was spitting out that same P0236 code. It was because the vacuum pump had failed.
I did a LOT of diagnosis, cleaning ground terminals, bought new boost control solenoid, baro/boost sensor and then finally checked the vacuum pump output. For some reason I had been thinking that the PO had just recently replaced the vacuum pump. Inches of vacuum was way down.
New vacuum pump and it has performed as it should until this time.

 

[patgallen]

i did away with my vacuum pump and put a manual waste gate control on the turbo. the only thing the vacuum pump controls is the waste gate on the turbo. it took me a few tries at the part store to get the right size belt I needed. i still get a boost circuit code every now and then but I am still adjusting the manual waste gate. my goal is to get it set to around 7 or 8 in of boost when it exceeds 8 it throws a boost sensor code. look over at LeRoy's diesel I believe that's where I got my waste gate condoler.

 

[patgallen]

sorry about the spelling my spell checker sorta over checks my words

 

[dbrannon79]

i did away with my vacuum pump and put a manual waste gate control on the turbo. the only thing the vacuum pump controls is the waste gate on the turbo. it took me a few tries at the part store to get the right size belt I needed. i still get a boost circuit code every now and then but I am still adjusting the manual waste gate. my goal is to get it set to around 7 or 8 in of boost when it exceeds 8 it throws a boost sensor code. look over at LeRoy's diesel I believe that's where I got my waste gate condoler.

You'll need to get you a boost fouler on there to get rid of the code. it's not that the engine doesn't like the 8psi. it's when you let off slightly on the pedal and your still running some PSI's the PCM wants to see little to no boost while cruising. before I tuned in mine, I was considering pulling the boost sensor from the intake leaving it connected to the harness while plugging the hole in the intake. that way the PCM would never see the boost. Not sure how it would have acted like that, I never tried it.

 

[Will L.]

Yeah, l besides the light being on- which Will keep happening. Tow a load up a hill one time and ot will set over-boost on accident.

You are loosing out on the proper power it originally had, and remember the job of the turbo is to take away over working the engine itself and to improve efficiency.
Turbo 6.2/6.5 lasts longer than non turbo, period. So factor that into the cost savings as well.

So options- search on here how to diy a “boost fooler”, or buy one ready made.
The other option is to get a tune which will modify that setting and also can help with whatever your main goal is. Want mpg- get a tune for it. Want power- get a tune for it.

Remember that a turbo can give you both more power and better mpg. Move up to a properly sized turbo with good airflow into and out of the truck- and you can see real nice improvements in both. Now think, if you have it built to handle more power for the few times you need it, but drive it easy and have it dialed in for better mpg… that is a recipe for longest life.