2006 Monterey Check Engine Light

[Richard Davis]

The Check Engine Light on my 2006 Monterey has come on.  The diagnostic flash code is a "25".  The Cat manual calls it a "Intake Air Pressure Sensor Failure".  My Silverleaf calls it "Boost Pressure Sensor - High Voltage".  The end result is the ECM shuts off the boost pressure calculation for the injectors.  So, I am driving this beast with no turbocharger boost.  I am puzzled by the "High Voltage" statement.  What does that mean?  I  am in Antonito Colorado in the middle of nowhere.  Does anyone have any idea where I can find a new boost sensor and someone to put it in for me?  I have kind of aged out of doing it myself.  I will attempt it if I must, but would prefer to let some one knowledgeable do it.  Also, if anyone knows the part # for a boost sensor for a CAT C9, I would appreciate it.
Thanks.  Richard

[Steve Huber Co-Admin]

Richard,
I replaced the boost pressure sensor in my C9 in 6/19. Part #s as follows.
  Sensor: 266-8650 but I think the updated # is 276-6793  Cost $166..05
  O ring: 214-7566   Cost $3.74
When ordering have your engine serial# handy to ensure the right sensor.
You may want to contact Dave Atherton (his phone# is in then member Directory) regarding your symptoms before throwing $ at the problem.
Steve

[Richard Davis]

Thanks Steve!
I have ordered the updated sensor with new O-ring.  Did you change it yourself?  I am in a National Forest campground and will have to do it myself.  I hope to not have any problems.
Richard

[Steve Huber Co-Admin]

Not too tough. Attached location diagram should help.
Steve

[Miriam Zimmerman]

Hey there!  Fellow 2006 Monterey owner and RV newbie.  I just had the check engine come on recently and not sure where to plug up (looking to buy reader from Amazon) for reading codes.  I was under the dash and can't find any port there.  Am I missing it or do I have to unhook something else to plug up?

Thanks in advance!

[Steve Huber Co-Admin]

See page 252 of the Owners Manual for location and a picture of the diagnostic plugs.
Steve

[Miriam Zimmerman]

Thank you, Steve!  I went to the manual and referred me to the 'engine pod' which I had never even considered removing that Velcro panel and was looking from under.  This was so helpful!  I found it and can get that code checked out.  Very grateful for the help!

[Richard Davis]

Miriam
You can also retrieve the "flash codes" from the ECM using the Engine Diagnostics button on the left console beside the driver.  A description of the process and the meaning of the light flashes is in the manual.  Good luck.
Richard

[Miriam Zimmerman]

I see that switch! Thank you - knowledge is power.  I'll look in the manual now to understand how to use. I'm not seeing the 'how' in manual, so I would assume coach has to be on. (Will wait for wife to do that) I just went through my Aladdin and nothing is coming up, so I'll have her start it later to check if that is why (manual doesn't say)

Does anyone have a suggestion for quality diagnostic reader? (Or not needed with onboard tools)

I have the 6 pin (J1708) but found Amazon has adapters, so I'm looking for a reader and we will keep handy or use the switch to see what code it gives later.

[Joel Ashley]

Miriam, reference this old thread:
http://beaveramb.org/forum/index.php/topic,10101.msg68805.html#msg68805

Joel

[Miriam Zimmerman]

This was very helpful.  I was able to retrieve the flash codes using the provided instruction and my engine diagnostic switch.  It actually came back with 3 codes and I just cross-referenced with the C9 manual provided over on BAC. I am curious if anyone has familiarity with these - and - how I know if they are 'active' codes or stored from prior.

codes are 38, 57, 25 (flashed in that order)

38 - An Inlet Air Temperature Sensor Fault 
I think this is my air heater and that dash light came on about a month ago, but, we are in FL and don't need it and was told it's not really 'important'. True?

57 - Transmission Datalink Engine Derate - and, I am having trouble googling any information on this, but will keep trying.  if anyone has insight, I would love the guidance.

25 An Inlet Air Pressure Sensor Circuit Fault - not sure about this, but the manual doesn't seem to think it's important and we will go to a CAT shop in Jan/Feb to check anyway.

[Richard Davis]

Miriam
The flash code "25" is a reference to the boost pressure sensor.  The manual seems to infer that it is not all that important, but I disagree.  If the sensor fails, your engine will still run, but it will have NO boost pressure.  No boost pressure means it will have very little acceleration.  I would recommend that you verify which sensor is actually installed on your engine.  Last Summer when I needed one, I looked it up on the CAT parts web site and ordered it.  The one they sent me was a newer version that did not fit my engine.  After removing the one on my engine and cleaning it off, I could read the part number printed on the side. My part was # 161-1704.  It has a 3-pin triangular shaped electric connector.  Good luck.
Richard   

[Miriam Zimmerman]

thanks, Richard - I will have to look into that, so thanks for pointing me in the right direction.  I am so grateful for others sharing their knowledge and experience - so invaluable for my learning journey!

[Joel Ashley]

Miriam, be advised that the connectors provided under the dash and in the battery or other area are best used by technicians using dedicated CAT diagnostic devices.  I’ve read that there can be risk of damage by users of aftermarket units.  Rely on the dash codes already available to you, otherwise consult a certified CAT service outlet that uses certified CAT diagnostic tools.

Joel

[Miriam Zimmerman]

thanks for that, Joel - fortunately, through help of others in this forum, I was able to retrieve the flash codes and we are planning on taking it to a CAT service center in Fort Myers when we leave the Keys.