Unsolved mysteries - 06 Diplomat

[Bob Nodine]

Things are a little slow around the house so thought I would seek some answers to things that have stumped me for years.

First let me say that we do not presently have any problems with the engine or ABS and are just trying to satisfy our curiosity.

First Mystery: What does the Eng Diag switch do. See photo. The owner's manual simply says "Checks engine functions" with no other explanation. It is located near the diagnostic port on the left of the steering column so we thought it might be used in conjunction with a device plugged into that port. We have owned this coach for 13 years and for 12 of those years the SilverLeaf has been plugged into that port. There is a port in the FRB and one in the engine compartment. A few years ago Bill Groves connected his laptop with Insight to the one in the engine compartment and the switch in question was not used.

 

Second Mystery: The user's manual says we have an ABS diagnostics center with a switch and indicator for troubleshooting the ABS system. For years I have looked for this module and have never found it. The manual says it is in the FRB but it is not there. The manual also gives instructions on how to use the ABS diagnostics center. There is a diagnostic port near the area where the manual says this diagnostics center should be located but I suspect it is just a third engine diagnostic port. I have attached photos of the manual pages and the port in the front run bay. If anyone who owns a 2006 Diplomat can help with these questions I would appreciate.

Edited December 15, 2020 by Bob Nodine

[Chuck B 2004 Windsor]

On my 2004 Windsor the ABS diagnostic module is located in the front bay below the drivers seat.  See picture.  In order for it to work properly, you need to follow the instruction in your manual.  Several years back, the going thing was to push the button about 25 times to activate it.  All that did was to disable the module leaving you with no ABS when the coach went into a skid on wet pavement.   Send me your PM to jbee99807@gmail.com and I will send you a picture.  Chuck B

ABS_Bendix.pdf

[granvillebarker]

My manual is in the coach in storage, but I think there’s a paragraph about using the engine diag button to get fault codes flashed similar to the abs.   I moved my silverleaf from my Windsor to my Dynasty when I got it 16 years ago, so I’ve never dealt with that either.

[Scotty Hutto]

Well, for once *maybe* I can answer a question for you, Bob.  Here’s how to use the Engine Diagnostic Switch...

Eng Diagnostic: Uses the Engine Warning and Stop Engine dash warning lamps to emit engine diagnostic codes. 

NOTE : To retrieve engine diagnostic codes requires an Insight Diagnostic Display or a Shorting Plug hooked to the engine diagnostic harness. 

To Retrieve Active Fault Codes: 

1. Tum the ignition key OFF. 

2. Hook up an Insight diagnostic display or Shorting Plug to the engine diagnostic harness. 

3. Tum the ignition key ON; observe Engine Warning and Stop Engine lamps. a. If no active codes are recorded, both lamps remain illuminated. b. If an active code is recorded, both the Engine Warning and Stop Engine dash warning lamps illuminate briefly then go out followed by the Engine Warning lamp illuminating briefly. This is an indication one or more fault codes will be displayed by the Stop Engine lamp. A three-digit code group displays as a series of blinks-pause-blinks-pause-blinks-pause. Record the code(s) as a three-digit number. Codes are separated or ended by the Engine Warning lamp flashing once. c. Use the Fast Idle switch to scroll through all ACTIVE faults. d. When codes are retrieved, tum OFF the Engine Diagnostic switch. e. Contact Cummins help line, I-800-DIESELS, or an authorized distributor. 

(from page 294 of the 2006 Dip owners manual) 😁

PS - Am I the only one that noticed the “supposed” location of the windshield washer reservoir?  Thank goodness they didn’t put it there in my coach!

[Bob Nodine]

2 hours ago, Scotty Hutto said:

Well, for once *maybe* I can answer a question for you, Bob.  Here’s how to use the Engine Diagnostic Switch...

Eng Diagnostic: Uses the Engine Warning and Stop Engine dash warning lamps to emit engine diagnostic codes. 

NOTE : To retrieve engine diagnostic codes requires an Insight Diagnostic Display or a Shorting Plug hooked to the engine diagnostic harness. 

To Retrieve Active Fault Codes: 

1. Tum the ignition key OFF. 

2. Hook up an Insight diagnostic display or Shorting Plug to the engine diagnostic harness. 

3. Tum the ignition key ON; observe Engine Warning and Stop Engine lamps. a. If no active codes are recorded, both lamps remain illuminated. b. If an active code is recorded, both the Engine Warning and Stop Engine dash warning lamps illuminate briefly then go out followed by the Engine Warning lamp illuminating briefly. This is an indication one or more fault codes will be displayed by the Stop Engine lamp. A three-digit code group displays as a series of blinks-pause-blinks-pause-blinks-pause. Record the code(s) as a three-digit number. Codes are separated or ended by the Engine Warning lamp flashing once. c. Use the Fast Idle switch to scroll through all ACTIVE faults. d. When codes are retrieved, tum OFF the Engine Diagnostic switch. e. Contact Cummins help line, I-800-DIESELS, or an authorized distributor. 

(from page 294 of the 2006 Dip owners manual) 😁

PS - Am I the only one that noticed the “supposed” location of the windshield washer reservoir?  Thank goodness they didn’t put it there in my coach!

Thanks Scotty. Yes I noticed the windshield washer reservoir but thought it must be a mistake. So you have not found the ABS board either? 

Edited December 16, 2020 by Bob Nodine

[Jeff H]

What does the "shorting plug" look like? 

Great questions Bob.  The ABS diagnostic might help explain the strangled beeping and ABS Light I get on wet roads.

[Steven P]

I learned a little when my transmission went out a month ago.  The transmission tech needed the diagnostic port for his computer to read the codes.  The FRB port and port under the steering wheel did not work.  The port (black, not gray) zip tied to the transmission dip stick under the bathroom access is for the transmission.  Once he hooked there, he had all the tranny info and once he fixed the wire, he rode there (hatch open) for a few miles to monitor the transmission.  

My port under the steering wheel is hooked to my Scan Gauge D and will give engine trouble codes.  I understand the FRB port to do the same, but I do not think I've tried it.  

[Doug Hoegh]

On 12/15/2020 at 4:41 AM, Bob Nodine said:

Things are a little slow around the house so thought I would seek some answers to things that have stumped me for years.

First let me say that we do not presently have any problems with the engine or ABS and are just trying to satisfy our curiosity.

First Mystery: What does the Eng Diag switch do. See photo. The owner's manual simply says "Checks engine functions" with no other explanation. It is located near the diagnostic port on the left of the steering column so we thought it might be used in conjunction with a device plugged into that port. We have owned this coach for 13 years and for 12 of those years the SilverLeaf has been plugged into that port. There is a port in the FRB and one in the engine compartment. A few years ago Bill Groves connected his laptop with Insight to the one in the engine compartment and the switch in question was not used.

 

Second Mystery: The user's manual says we have an ABS diagnostics center with a switch and indicator for troubleshooting the ABS system. For years I have looked for this module and have never found it. The manual says it is in the FRB but it is not there. The manual also gives instructions on how to use the ABS diagnostics center. There is a diagnostic port near the area where the manual says this diagnostics center should be located but I suspect it is just a third engine diagnostic port. I have attached photos of the manual pages and the port in the front run bay. If anyone who owns a 2006 Diplomat can help with these questions I would appreciate.

Bob I also have a 2006 Diplomat and lost an ABS wheel sensor a couple of years ago.  After searching I found the Bendix module under the shift pad and leveling panel.  I was able to trigger the error codes by jumping a couple of the pins on one of the connectors at the box.  I too have always wondered why I don't have the diagnostic board many seem to have in the front run bay.  I do have an extra J1939 and assume it's connected to the Bendix box but have never confirmed.  I have the pdf file of the Bendix box if you would like a copy.

[Bob Nodine]

1 hour ago, Doug Hoegh said:

Bob I also have a 2006 Diplomat and lost an ABS wheel sensor a couple of years ago.  After searching I found the Bendix module under the shift pad and leveling panel.  I was able to trigger the error codes by jumping a couple of the pins on one of the connectors at the box.  I too have always wondered why I don't have the diagnostic board many seem to have in the front run bay.  I do have an extra J1939 and assume it's connected to the Bendix box but have never confirmed.  I have the pdf file of the Bendix box if you would like a copy.

Sure Doug, never hurts to have a document on hand just in case one needs it.

4 hours ago, Steven P said:

I learned a little when my transmission went out a month ago.  The transmission tech needed the diagnostic port for his computer to read the codes.  The FRB port and port under the steering wheel did not work.  The port (black, not gray) zip tied to the transmission dip stick under the bathroom access is for the transmission.  Once he hooked there, he had all the tranny info and once he fixed the wire, he rode there (hatch open) for a few miles to monitor the transmission.  

My port under the steering wheel is hooked to my Scan Gauge D and will give engine trouble codes.  I understand the FRB port to do the same, but I do not think I've tried it.  

Steve,

The diagnostic port of the Allison on our coach is in the front run bay mounted on the right hand side. It has a cover over it and is rectangular in shape. I just happen to have a photo.

[Steven P]

@Bob Nodine

That's crazy.  The tech started there and I do not have that port that you have.  And mine is round instead of rectangular.  How about you @Scotty Hutto?  @Doug Hoegh?  I checked but do not have a pic on me.  

[Doug Hoegh]

4 hours ago, Bob Nodine said:

Sure Doug, never hurts to have a document on hand just in case one needs it.

Steve,

The diagnostic port of the Allison on our coach is in the front run bay mounted on the right hand side. It has a cover over it and is rectangular in shape. I just happen to have a photo.

Bendix EC-60 ABS/ATC/ESP Controllers Service Manual

Bendix EC-60 ABS:ATC:ESP Controllers Service Manual.pdf

1 hour ago, Steven P said:

@Bob Nodine

That's crazy.  The tech started there and I do not have that port that you have.  And mine is round instead of rectangular.  How about you @Scotty Hutto?  @Doug Hoegh?  I checked but do not have a pic on me.  

Steve I have a round J1939 in the front run bay that I assume (I've never tested it) is the connection for the ABS system  This booklet I just posted for Bob shows a diagnostic tool that plugs into such a port. 

[Jeff H]

12 hours ago, Steven P said:

@Bob Nodine

That's crazy.  The tech started there and I do not have that port that you have.  And mine is round instead of rectangular.  How about you @Scotty Hutto?  @Doug Hoegh?  I checked but do not have a pic on me.  

I have that connector in the same place on my Diplomat.

Dumb question but were the Diplomats made in Indiana and Oregon?  Could that be the difference?

[Bob Nodine]

14 hours ago, Doug Hoegh said:

Bendix EC-60 ABS/ATC/ESP Controllers Service Manual

Bendix EC-60 ABS:ATC:ESP Controllers Service Manual.pdf 5.17 MB · 10 downloads

Steve I have a round J1939 in the front run bay that I assume (I've never tested it) is the connection for the ABS system  This booklet I just posted for Bob shows a diagnostic tool that plugs into such a port. 

Thanks Doug, I just downloaded it.

[Doug Hoegh]

4 hours ago, Jeff H said:

I have that connector in the same place on my Diplomat.

Dumb question but were the Diplomats made in Indiana and Oregon?  Could that be the difference?

My understanding is all Diplomats were manufactured in Wakarusa.  We had our floor upgraded a couple of years ago by a company called New Debut. Their shop is in one of the buildings that was part of the original Monaco campus. It’s a big place.

[Dennis H]

On 12/16/2020 at 3:03 AM, Jeff H said:

What does the "shorting plug" look like? 

Great questions Bob.  The ABS diagnostic might help explain the strangled beeping and ABS Light I get on wet roads.