BAC Forum
General Boards => Technical Support => Topic started by: Bill Laatz on September 21, 2016, 04:56:00 PM
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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
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Bill, disconnect connector at actuator and plug in and out several times may be dirty connection
Dave Atherton Retired Cat Mechanic
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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!!
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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
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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???
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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
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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.
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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
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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
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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
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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
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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??
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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.
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Bill, can you call me 605 999-0720 and will try to take you through problem over phone.
Dave
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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
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Bill, now that we know what going on here is the information for wiring of Accelerator
Actuator. Actuator first, sensor/switch sensor common. bK. B
+ 8 Volt. RD. A
Actuator Petal Position. WH. C
J-1 ECM H-975. PK. Sensor/switch common
C-985. BU. 8 Volt
C-986. BR. Actuator Pedal Position
Check and see is Allen Hex bolt on J-1 ECM 70 pin connector is tight ( looking at ECM closest to front )
Take each wire at actuator and follow to connection. check the ground wire BK for good ground
The voltage you can check with engine running. Dave Atherton Retired Cat Mechanic
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Dave, thanks a million for all your help and information both on and off the forum. I had to give up because some of the items to check were to difficult to get to. I had it towed to a Caterpillar shop, and they found one of the connectors to the ECM had coolant in it and one of the pins was corroded off - you said to check this connector-great call!!! They replaced the ECM $$$$$ and also replaced the connector to the ECM and the connector to the coolant level sensor. The throttle position sensor and the coolant level sensor that I replaced were both still good. Because of removing the axle shaft for the tow, and my draining the coolant reservoir, I had both drained and replaced. My total bill was$2,720.66 parts and $1,960.00 labor and $229.36 misc for a total of $4,910.02 plus the parts I purchased and installed cost $283.28 for a grand total of $5,193.30 to get back on the road, and $450 for towing which will be covered by AAA. Attached is a picture of the main problem - still do not know how the coolant got into the connector.
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Bill, thanks for update on engine problem. One thing that seems to be questioned, Dave
Provides factual information with his Caterpillar background but not knowing how much a
person can do himself information is present. I feel the BAC Forum is a great tool to choose from.
Something a person does not know when Dave uses Cat ET computer on members motorhome,
and gives Diagnostic ECM fault code readout and printout. The Cat ECM configuration is printed out
as backup for events as above pictures show when programming new replacement ECM. The
Caterpillar Dealer was very fair with total billing for work. Dave Atherton Retired Cat Mechanic