Codes after throttle position sensor change

After posting this, I was told by a mechanic that I need to reset the PCM by pulling the negative battery post off. I did this. Left it off for fifteen minutes. Now my truck will not crank at all. I need some serious help here.

Good morning.

If you did something wrong with the TPS, it would have coded for the TPS which it has not.

The 171,174 looks like a vacuum leak. That is the main cause for those codes. The engine is running too lean.

430 is a catalytic converter code. Bank 2 catalytic converter is bad and has to be replaced.

Resetting codes does nothing. The issues need to be addressed, diagnosed, repairs made and then they can be cleared.

From the looks of it, nothing had to do with your repair. Before you cleared the codes, did you notice when they were set? The number of counts on the codes?

Most likely they were there prior to the repair from the symptoms that you described. Rough running is not the TPS sensor. That is engine related.

As far as the no start, does it crank over or does do nothing when you turn to start?

Roy

430

P0430
Descriptor
Catalyst System Efficiency Below Threshold (Bank 2)
Probable Causes
Catalytic Converter Damaged
Cylinder Misfire
Downstream Heated Oxygen Sensor (HO2S) Wires Improperly Connected
Exhaust Manifold Damaged
Exhaust System Pipe Damaged
Fuel Pressure Incorrect (Excessive)
Heated Oxygen Sensor (HO2S)
Ignition Timing Retarded
Leaded Fuel
Malfunctioning Engine Coolant Temperature (ECT) Sensor
Muffler and Tailpipe Assembly Damaged
Oil Contaminated

171,174

P0171
Descriptor
System To Lean (Bank 1)
Probable Causes
Air Leaks After Mass Air Flow (MAF) Sensor
Cam Timing
Cylinder Compression
Exhaust Gas Recirculation (EGR) Valve Stuck
Exhaust Leaks Before or Near Heated Oxygen Sensors (HO2S)
Fuel Injectors Leaking or Contaminated
Fuel Pressure Excessive
Fuel Pressure Regulator Leaking
Gasket Leaking
Improperly Seated Engine Oil Dipstick
Leaking Diaphragm or EGR Vacuum Regulator (EVR)
Low Fuel Pressure or Running Out of Fuel
Oil Overfill
Positive Crankcase Ventilation (PCV) System
Vacuum Leaks
Vapor Recovery System

c016

There were no codes prior to resetting the PCM. I was told to do it after I changed the TPS. The truck was running fine. The mechanic told me to change the TPS due to the rough idle on cold starts and reset the PCM afterwards. If the repair does not have anything to do with this, then why did I not have the codes show up before?

Yes, it cranks over but will not start.

I wonder if the PCM compensated from the errors before and I erased the adaptive memory.

You did not erase the adaptive memory. You just made the PCM forget the codes.

Did you check for fuel pressure and spark?

Roy

I do not have the proper equipment to test it. I just cannot understand for the life of me why it runs great. Then after the part install and quick code reset, the fuel pressure or any other problem would occur. Nothing really changed.

What is the likelihood that it could have blown a fuse?

This is why you need to check for spark and fuel.

Try spraying some starter fluid in the air filter and see if it start and stalls.

When you crank the engine, does the tachometer move up a little to reflect rpm?

It could be a fuse, but you would also need to find out why it failed. Just replacing it does nothing as it will happen again.

Roy

So I sprayed some starter fluid in the air filter and it finally started. I am getting a P1121 code and that is all. So I take it for a drive and it does not get out of first gear. What could be causing this?

I cut the truck off and now it will not start back.

I would check the fuel pressure. It sounds like you have low fuel pressure.

1121 is for TPS. Make sure it is mounted correctly, the connector is tight and clean and it is adjusted correctly. This is the sensor that controls transmission shifting.

Key on, engine off, you should have .5 volts on the signal wire. Push down the fuel pedal and the voltage should rise to 4.8 volts at full throttle.

Roy

P1121
Descriptor
Throttle Position (Tp) Sensor Inconsistent With MAF Sensor
Probable Causes
Air Leak (Vacuum Leak) Between Mass Air Flow (MAF) Sensor and Throttle Body
Mass Air Flow (MAF) Sensor Damaged
Throttle Position (TP) Sensor Damaged
Throttle Position (TP) Sensor Not Seated Properly

It was mounted by two simple screws and its tight. As far as adjusted, I did not adjust anything. I just mounted it.

You will need a scan tool to monitor the actual voltage at idle and full throttle or back probe the signal wire and check with a volt meter.

Roy

Thanks Roy.

You are welcome.

Glad to help.

Oh, also what is your opinion as to why my transmission is in safe mode and not getting out of first gear? There is plenty of transmission fluid. I will get to the bottom of the fuel and spark testing but will a brand new installed TPS cause activation of transmission safe mode? How does this get fixed?. Like I said, I am getting p1121 so how do I get the TPS and MAF into sync? Give me your full thoughts on this please and I will get out of your hair, lol.

The TPS is the main sensor that controls transmission shifting times. If you did not have an issue prior to your repair and you now have this issue, it may be the brand TPS you are using. I would get an OEM sensor and you will need to check the voltages as I suggested a couple of times.

The transmission is not in safe mode, it is just not shifting due to lack of signal to allow it to shift.

Roy

Everything you suggested is getting done. I cannot personally do it because I do not have that type of scan tool.

What are the chances that the new TPS can cause the crank but no start?

Just want to report back to tell you the conclusion. The TPS was not calibrated when I put it on. The PCM also had to learn it. So, this the cause of not getting out of first gear and cranking but no start. Now it is running like a champ like it did before, although the TPS was never the idle issue.

Yes, like I said before, the TPS had nothing to do with the rough running.

Glad to hear you are running.

Roy