2006 APPS Code P2127 need wiring info

[navyjoe]

I am still having a problem with this code popping up. The code reads "Throttle /pedal position sensor / switch E circuit low". I seem to recall that this assembly apove the accelerator has 2 components. A switch and a variable resistor. This sounds like it is the switch part of the circuit. I have unplugged and reconnected the connector on the pedal, now I would like to investigate the wiring associated with it. What other common components share this wiring with this connector pin? Could it be a ground connection? Anyone have a wiring diagram of this? I can't find one on the internet anywhere. I hate to start parts replacement without a little more trouble shooting.

Another question. Is it ok to disassemble this plastic box above the pedal. Are there more connectors inside of it?

Thanks, Joe

 

[Bob4x4]

Sensor-accelerator pedal position (5.7l/diesel) - black 6 way cav circuit function
1 f856 20yl/pk 5 volt supply
1 k854 20vt/br (diesel) 5 volt supply
2 k29 20wt/br apps no. 2 signal
3 k400 20br/vt apps no. 2 return
4 k167 20br/yl apps no. 1 return
5 k23 20br/wt apps no. 1 signal
6 f855 20pk/yl 5 volt supply
6 k852 20br/vt (diesel) 5 volt supply

 

[sag2]

View attachment 2006 APPS.pdf

Here is a diagram. Check the inline connectors.

 

[navyjoe]

Thanks sag2,

Now I have more work to do, really do appreciate the diagram. I guess I'm going to have to buy the service manuals. I suspect I will have more and more electrical problems as time goes on. The truck is now 7 years old so age is takinging its toll.

 

[Prairie Dog]

Judging from the attachment Sag posted, there's no switch in it. The average APPS (or what ever a manufacturer wants to cal it) has two hall effect sensors in it that should always match so if one has a failure then the ECM see's a difference between them and throws a code. They were made with variable resistors years ago but as far as I know, nobody does it that way anymore - there was just too to go wrong. Someone correct me if I'm wrong about the Dodge application ( I know Dodge has a hard time letting go of old technology sometimes).
If it still throws the same code after replacement then either the new APPS is bad or more likely, the wiring or connections are at fault.

Scott

 

[Bob4x4]

The Accelerator Pedal Position Sensor (APPS) provides the Engine Control Module (ECM) with two DC voltage signals which change as the position of the accelerator pedal changes. One of the DC voltage signals will be half the voltage of the other signal.

 

[Bob4x4]

The k29 and f856 ckts are the ones critical to this dtc

 

[navyjoe]

Judging from the attachment Sag posted, there's no switch in it. The average APPS (or what ever a manufacturer wants to cal it) has two hall effect sensors in it that should always match so if one has a failure then the ECM see's a difference between them and throws a code. They were made with variable resistors years ago but as far as I know, nobody does it that way anymore - there was just too to go wrong. Someone correct me if I'm wrong about the Dodge application ( I know Dodge has a hard time letting go of old technology sometimes).
If it still throws the same code after replacement then either the new APPS is bad or more likely, the wiring or connections are at fault.

Scott

I think you are correct. I read in another post that Dodge uses a tecnique called differential signaling. It basically uses 2 wires for the same signal as a safey measure. So each line, 5 volt, signal 1 and signal 2 use 2 wire technology so the computer can detect if there is a wiring issue. It also minimizes noise.

 

[sag2]

As far as I know the APPS is not a hall effect, it is a variable resistor. Two circuits are used as a safety, as Bob said, one voltage is always 1/2 of the other. That gives two inputs as well as a rationality piece so the ECM can detect failure on one or both circuits. This is no different than most other vehicles use in the industry.

 

[Prairie Dog]

I kinda suspected Dodge would still be using that technology.

 

[navyjoe]

As far as I know the APPS is not a hall effect, it is a variable resistor. Two circuits are used as a safety, as Bob said, one voltage is always 1/2 of the other. That gives two inputs as well as a rationality piece so the ECM can detect failure on one or both circuits. This is no different than most other vehicles use in the industry.

Take a look at this. Looks familiar from some of the parts pictures I've seen for the APPS.

http://www.wellsve.com/video_cummins_tps.html

Also using 2 wires for each terminal of a device is a pretty common technique for failsafe wiring. I allows for electronic monitoring of the conductor independent of the signal passing thru it. I suspect this is the case here too.