Hi Bruce and others
I notice your in Plano, Tx
I just moved from Oregon to Greenville, Tx which is just east of you
I used to work for GM at the Tech center in Warren, Mi back in mid 1980s to early 1990s
Frankly you need to find a better dealer or shop as their diagnostics game plan is lacking
So just doing some thinking
1. PCM uses a 5 volt ref to several engin sensors such as CAM, Crank, TPS, APP, MAF, AIR, etc. So if the fuse for 5 volt (of PCM) or the PCM itself was faulty there would be a lot more problems and DTCs tripped so to me that leaves it is not a PCM issue
2. You did not mention if the engine goes into limp mode, if it does I would go right to diag APP (gas pedal and TPS) as 2 of your DTCs are drive by wire issues. Depending on model year APP consists of 2 or 3 pots, the TAC (DBW controller) is doing multi checks to assure APP is not faulty and would cause a run away vehicle and cause a crash. Simply with a good OBD-II scanner (as I show below ) even with just key on, engine off APP and TPS can be seen if APP and TPS agree or not.
3. Also, can use the scanner to see if 5 volt ref is functional
4. Should be checking for TSBs for that vehicle as many times the problems are weak crimps of wiring pins or the wiring loom has no slack such as to APP and causes stress to wiring pins connections
As example :
Update for Inventory and Customer Vehicles Main Engine Harness Wire Chafe Expires with Base Warranty
MODELS:2016 Cadillac ATS-V
This service update includes vehicles in dealer inventory and customer vehicles that return to the dealership for any reason. This bulletin will expire at the end of the involved vehicle's New Vehicle Limited Warranty period.
This bulletin provides a service procedure to inspect and, if necessary, reposition the main engine-wiring harness on certain2016 model year Cadillac ATS-V vehicles.
In some of these vehicles, the orientation of the main-engine wiring harness could cause the wires to contact and chafe against the right-front valve cover bolt and washer. If the engine-wiring harness insulation is compromised, the vehicle’s tachometer, powertrain, and automatic-braking systems could be effected. While this condition could—if uncorrected—cause a loss of propulsion or the activation of the automatic braking system, GM has no reports indicating that either event has occurred on a vehicle in the field.
This service procedure should be completed as soon as possible on involved vehicles currently in dealer inventory and customer vehicles that return to the dealer for any type of service during the New Vehicle Limited Warranty coverage period.
So check for other TSBs such as
VEHICLES INVOLVED 16 ATS-V TSBS
Check for how the DTCs are defined will help zoom into the areas to look at first such as :
Symptoms of a P2135 code can range from stalling when you come to a stop, total lack of power, no acceleration, sudden loss of power at cruise speeds or stuck throttle at current rpm.
Additionally, the check engine light will illuminate and the code will be set. Potential Causes of P2135 DTC It's been my experience that the wiring connector or "pig tail" on the throttle body gives problems in the form of a poor connection.The female terminals on the pigtail corrode or pull out of the connector.
Possible bare wire on pigtail shorting to ground.
The top cover on the throttle body distorted preventing the gears from turning properly. The electronic throttle body is faulty. The accelerator pedal sensor or its wiring failed.
The engine management computer has failed.
The TPS sensors were not correlating for a few seconds and the computer needs to be cycled through its relearn phase to restore active response to the throttle body, or the computer needs reprogramming at the dealer.
Diagnostic / Repair Steps A few points about the electronically controlled throttle.
This system is incredibly sensitive and vulnerable to damage, more than any other system. Handle it and its components with extreme care. One drop or rough handling and it's history. Apart from the accelerator pedal sensor, the remainder of the components is in the throttle body.
On inspection, you will notice a flat plastic cover on the top of the throttle body. This houses the gears to actuate the throttle plate.
The motor has a small metal gear protruding up through the housing under the cover. It drives a large "plastic" gear attached to the throttle plate.
The pin that centers and supports the gear fits into the throttle body housing and the top pin fits into the "thin" plastic cover.
If the cover is distorted in any way, the gear will be compromised requiring total replacement of the throttle body.
Pull the electrical connector out of the throttle body. Inspect it closely for missing or bent female terminals. Look for corrosion. Clean any corrosion using a small pocket screwdriver. Place a small amount of electrical grease on the terminals and reconnect it.
If the terminal connector has bent or missing pins you can pick up a new "pigtail" at most auto parts stores or from the dealer. Inspect the top cover on the throttle body for cracks or warping. If any are present, call the dealer and ask if they sell just the top cover.
If not, replace the throttle body. With a voltmeter, probe the accelerator pedal sensor. It will have 5 volts for reference and next to it a varying signal.
Turn the key on and slowly depress the pedal. The voltage should climb from .5 to 5.0 smoothly.
Replace it if the voltage spikes or it has no voltage at the signal wire.
Look online for wire terminal identification on the throttle body of your vehicle. Probe the throttle body connector for power to the throttle motor.
Have a helper turn the key on and slightly depress the pedal. If no power is present, the computer is at fault. If there is power the throttle body is malfunctioning.
If problem is resolved, problems still might happen but it could be now that APP and TPS are NOT rezoned to PCM
Some GM makes to rezone TPS as to angle of TB butterfly is with key on, engine off, disconnect the wiring connector of TPS
PCM will trip a TPS DTC and set TPS angle at zero angle, go key off, plug TPS connector back in, turn key back on and PCM will rezone TPS angle to zero, Clear any DTCs
JR _ Team ZR-1 Corvette Racing - Custom GM PCM and TCM Tuning