Accelerator not responding

[Bill Laatz]

URGENT NEED OF HELP!!
Ready to leave a MI campground, started engine, check engine light flashes, accelerator does not respond, engine idles fine.  Silverleaf says
"eng pid 91 8 Accelerator pedal position   frequency error".  Transmission will shift into gear and move.  2006 Beaver Marquis C-13 Cat

[Dave Atherton]

Bill, disconnect connector at actuator and plug in and out several times may be dirty connection
Dave Atherton Retired Cat Mechanic

[Bill Laatz]

There is no connector at the pedal, I followed the 3 wires up under the dash where they are in mass with others.  I will try to follow it.  Thanks!!

[Dave Atherton]

Bill, location should be around pedal upper part. Looking now at Cat Sis for more information.
What I do know engine will remain at idle untill we can clear code. Will take a few minutes to
get information. Dave

[Bill Laatz]

I unwrapped all the wires under the dash and found the connector, unplugged several times, tried the accelerator with it plugged together and also unplugged - no change from engine idle.  The wires are white-cat 66, red-cat 04, black-cat 05.  There are two large philips screws on what I would call the sender box on the accelerator pedal - I tried to remove them, they turn, but do not release the cover.  Any more ideas???

[Gerald Farris]

Bill,
If you can not locate a bad connection in the wiring to your accelerator pedal, you may have a bad sensor in the pedal assembly, but it will require a computer connection to the coach at a Cat repair facility to verify that. However, you can monitor the accelerator position on your Silverleaf and possibly determine by it's signal there if the pedal sensor is at fault (intermittent signal as pedal is moved) or if it is in the wiring (no signal or intermittent as connectors are moved).

Gerald   

[Bill Laatz]

Prior to this problem, I had a failure of the engine coolant level switch, which I disconnected, the "check engine" light came on blinking, but I ignored it and monitored the coolant temperature and stopped to check the reservoir level on my trip to the camp.  I was going to replace the sensor upon returning home 80 miles away.  Is this related in any way??

Cat Engine Info
serial   KCB47905
AR   260-2870
core AR   259-8885
OEM #   01807698
FLS intercept   -18
ECM software   272-3131
perf spec   OK-6293

Also, my silverleaf PC just stopped giving me engine data and I am rebooting the computer.

[Dave Atherton]

Bill, accelerator pedal position sensor sends a pulse width modulated signal to ECM.
The part Number for throttle position sensor  266-1466 . Would suggest remove the
Two little bolts that holds sensor in place and remove, these are not known to be
problematic. Along side of sensor you should see the actuator where it get it movement
move that with engine running to see if responding many times out of adjustment.
Dave

[Dave Atherton]

Bill, yes the coolant would present problem and keep engine in the Cold Mode which would affect
Acceleration Response. Think we are going in wrong direction here. Dave

[Bill Laatz]

Is there any way I can bypass the level sensor?  It has 4 white wires that look like cat 54, cat 49, cat 18, cat 02.  The level sensor was leaking a small amount of coolant into the electrical plug, so I disconnected it, blew it out with air pressure, and let it set in the sun for three days to dry out.  I have reinstalled it, added the coolant back in the reservoir, and tried the accelerator with the electrical plug both connected and disconnected.  Still no RPM increase

[Dave Atherton]

Bill,  wire on engine side ( not level sensor ). G 879 OR    5 volt ,  C 983 WT Coolant level normal,
C 984 YL  Coolant Level Low,  H 795 PK.  On female side of connector top will have flat and pin
At  top is A,  pin at bottom is B,  pin at middle right is C,   Pin in middle left side is D

Pin A is coolant level low,   Pin B is sensor / switch sensor return,  pin C. 5 volt sensor supply,
Pin D coolant level level normal.  Turn key on and measure voltage. Pin C to pin B sensor switch
return. The measured voltage should be between 4.5 Volt and 5.5 volt  if voltage is not in above
range the problem is with sensor supply. Create a short or bypass  to normal coolant level
connect jumper wire to pin A and Pin B  Dave Atherton Retired Cat Mechanic

[Bill Laatz]

Dave, thanks for all your help so far - I owe you!!!
The voltages check at:
A-B   7.08
A-C   7.08
A-D   5.02
B-C   4.63
B-D   6.70
C-D   2.07
Should I now jumper A to B??

[Bill Laatz]

The attached photo shows the plug.  I considered the upper pin next to the notch A, directly under it B, to the right C, and on the left D.  I tried the A to B jumper with a paper clip, and no change. 

[Dave Atherton]

Bill, can you call me 605 999-0720 and will try to take you through problem over phone.
Dave

[Bill Laatz]

Dave,
What if I increase the idle speed with the cruise control buttons and put it in gear?  Will the transmission be able to deal with the set rpm and shift through the gears?  Is there any way I can limp home 80 miles with some stop-and-go traffic and 60 miles of interstate?
Bill Laatz