Electronic throttle issues

[xyrob]

This might be a really quick fix:
The electronic throttle on my 2015 Ram 1500 5.7 stopped working after I did some other work (probably was going bad and I bumped it a few times). The position sensor outputs weren't changing even if I moved the throttle plate by hand so I replaced it. With the new throttle body, the position sensor is responding correctly to movement, but the truck is still stuck in limp home mode and has electronic throttle control faults.

Looking at alfaOBD, I see a bunch of codes but they all say test not complete. I also haven't seen the throttle plate move at all. Is the throttle just locked out until it passes the tests, and is there a way to get it to run those? Or is it more likely still having a real problem?

 

[Ken226]

Done a electronic throttle relearn?

You can do it with Alfa, a scan tool, or if you search you'll find a procedure to do it without Alfa or a scan tool.

 

[xyrob]

Yep, I tried doing it with Alfa. It didn't seem to change anything.

 

[Ken226]

I'm not sure.

Tried removing the battery terminals, touching them together? To reset the whole system

 

[xyrob]

I will try that in a bit. I did try disconnecting the battery for a few minutes, but it's possible it wasn't enough to reset everything.

Also, the faults are:

Error code: P2135
Throttle Position Sensor 1/2 Correlation
Test not complete
Error present
Error warning lamp 'ON' requested
Error code: P0642
Sensor Reference Voltage 1 Circuit Low
Test not complete
Error present
Error warning lamp 'ON' requested
Error code: P2122
Accelerator Pedal Position Sensor 1 Circuit Low
Test not complete
Error present
Error warning lamp 'ON' requested
Error code: P2167
Accelerator Pedal Position Sensor 2 Maximum Stop Performance
Test not complete
Error present
Error warning lamp 'ON' requested
Error code: P2166
Accelerator Pedal Position Sensor 1 Maximum Stop Performance
Test not complete
Error present
Error warning lamp 'ON' requested
Error code: P2116
Accelerator Pedal Position Sensor 2 Minimum Stop Performance
Test not complete
Error present
Error warning lamp 'ON' requested
Error code: P2115
Accelerator Pedal Position Sensor 1 Minimum Stop Performance
Test not complete
Error present
Error warning lamp 'ON' requested

That does seem like a calibration issue.

I attached a graph of the throttle signals when opening the throttle plate by hand. They seem correct based on what I've read, though it looks like the calculated throttle position % is stuck at 167% (probably just not calibrated).

 

[Ken226]

I'm assuming the learn procedure you did?

I think the other is just a sensor calibration.

 

[xyrob]

Yep. I've tried it a few times. I'm not 100% sure whether it wants me to turn the ignition off and on, or start and stop the engine when it get to "Cycle ignition" at the end, but I've tried both.

 

[diymirage]

I should have a stock throttle body from my '17 5.7 kicking around, if you need to replace yours

 

[xyrob]

Thanks for the offer and the help! I think the throttle body is good (fingers crossed!) and it's all working now. I disconnected the battery and grounded the 12V bus to discharge everything. THAT solved the throttle body related codes and the truck would idle well but not accept accelerator pedal input. I then had to run the "Learn ETC,Learn ETC (NGC4)" to get the pedal re-calibrated. That got back throttle control, then I just had to reset a related transmission code to clear the check engine light.

As a bonus, I think I'm getting stronger startups and smoother idling now. The old throttle had some carbon buildup and something was obviously going bad on the sensor board. That might explain why it would occasionally die at startup.