Good afternoon everyone,

As the title implies, I have a 2009 H3 Adventure with 132,000 on the odometer. About 3 or 4 weeks ago I started to hear what sounded like pre ignition (pinging) but other than that the truck was running fine. Last week it started "surging" while at constant throttle settings, e.g., cruising at a constant speed, but CEL was clear. A search of the forum returned a few possible culprits, but I wanted to get additional data to narrow down the possibilities instead of just throwing money and time at it. I installed Torque Pro a couple of days ago and had been graphing the performance of MAF/TPS/Accelerator position/Etc. etc. and still no CEL/Fault Codes.

The finally CEL woke up last night and threw a P0300 error, which unfortunately is pretty generic and got me no closer to narrowing down the source of the problem. Thankfully (can't believe I'm saying that) this morning the flood gates opened and I got a cascade of error warnings: Service: Stab Sys, Traction Failed, Reduced Power.I managed to get it back home and into the garage, took a look at Torque Pro which had been running:

​​​​​​Current Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected

Pending Fault Log
------------------
ECU reports no pending faults

Historic Fault Log
------------------
P2135: Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged

Based on this info, my question for you guys is where to start? Obviously the Throttle Body and Accelerator Pedal Assy's, but based on your experience, would you do Throttle Body first, then Accelerator Pedal Assy or vice versa or both together?

As always, appreciate the assistance.

 

When was the last time you cleaned the Throttle Body (TB) with TB cleaner? I would start there, and use CRC electronics cleaner on the both sides of the electrical connections at the TB and Accelerator Pedal before replacing anything.

Simple stuff first.

Good luck.

 

As recommended I cleaned the TB today, as well as the MAF, and all associated electrical connections. The TB was pretty dirty, and is significantly cleaner now. I just got it buttoned back up and started it and it is running really rough. The CEL is reporting the messages Service: Stab Sys, Traction Failed, Reduced Power again. When I checked for fault codes I get a P2176.

​​​​​​Current Fault Log
------------------
ECU reports no current faults

Pending Fault Log
------------------
P2176: Throttle Actuator Control System - Idle Position Not Learned

Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged

As I had read a previous post of yours (https://www.hummerforums.com/forum/h...97&postcount=2) re. the procedure post TB install I did not touch the throttle, but shut it down after several minutes as it was shaking pretty bad. It sounds like I am going to have to let it run until it "learns" the throttle idle position, but it was shaking really bad so I thought it best to run this up the flagpole first to see if it is normal.

Any advice would be greatly appreciated.

 

1-06-04-007B

 

Thanks @hummerz . Unfortunately I'm not getting the P2135 error code any longer.

A rescan after all the work yesterday is now returning these:

​​​​​​Current Fault Log
------------------
ECU reports no current faults

Pending Fault Log
------------------
B2AAA: Unknown code - More information may be available on the web
P0223: Throttle/Pedal Position Sensor/Switch "B" Circuit High Input
P2176: Throttle Actuator Control System - Idle Position Not Learned

Historic Fault Log
------------------
P0122: Throttle/Pedal Position Sensor/Switch A Circuit Low Input
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged

At least it was drivable before, albeit with intermittent surging and occasional CEL's which always cleared themselves after a couple of cycles. Just tore it down again and going thru the assembly to make sure I didn't miss anything. As far as diagnostics are concerned, the only difference before/after is that absolute throttle is higher... about 32%.

 

Latest update... tore the induction system down to the manifold, gave the TB another thorough cleaning, liberal amounts of TB cleaner this time, buttoned everything back up, crossed my fingers and started it. Everything seemed perfect, idle was right on the money, so I let it sit for about 12 minutes, just to play it safe. Unfortunately, it only seemed perfect... it is not responding to any throttle pedal input, even tho diagnostic of throttle pedal sensor shows that it is working, and the voltage difference between pedal sensor D and E is steady at 50% so I don't think that is the problem.

Anyway, here are the fault codes:

Current Fault Log
------------------
ECU reports no current faults

Pending Fault Log
------------------
P2101: Throttle Actuator Control Motor Circuit Range/Performance

Historic Fault Log
------------------
B2AAA: Unknown code - More information may be available on the web
P0122: Throttle/Pedal Position Sensor/Switch A Circuit Low Input
P0223: Throttle/Pedal Position Sensor/Switch "B" Circuit High Input
P2176: Throttle Actuator Control System - Idle Position Not Learned
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged

Am ordering a replacement TB this evening... Time is worth a lot more than money and I've spent enough at this point. If anybody can think of anything else I should be looking at, by all means let me know. And again, thanks for the help up to this point, it is greatly apprecaited.

 

If you cleaned the throttle body by moving the butterfly without disconnecting, you will need to relearn. Fyi, proper way to clean throttle body while mounted/connected is to depress the accelerator pedal(APP) to open the butterfly(TAC).

 

Bulletin No.: 14582

 

You are a wealth of information with regards to these service bulletins sir... thank you!

As far as my particular case, I did in fact remove the throttle body completely from the vehicle, and took it to Santa's workshop for cleaning. Pics showing before and after are below:





As far as the current issue is concerned, irregardless of the error codes, the truck starts perfectly, and idles perfectly but the throttle body is not responding to any pedal input. OBD monitoring of the pedal sensors (PedalD/PedalE) shows that they appear to be functioning within spec. Any ideas?

 

BTW, after clearing the CEL and running the diagnostics again, the only error code I am getting now is P2101. This is admittedly casting a fairly wide net, as there could be any one or several components, e.g., TB, Pedal Assy, PCM, Harnesses, etc., contributing to this.

As before, I appreciate the help, and anything any of you can think of will help.