Author Topic: Code 71 and a request to Dave Atherton for C12 Test information  (Read 5113 times)

Bill Borden

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Hey Dave,

When you have time could you post the test information on my motor.  We have a 2000 PAT C12 425, serial # 2KS27870.  We have owned this coach for 6 years and love it, no major problems so far. 

But I do have a couple of questions, one is I that have noticed a higher Oil pressure level on your test data for the different C12 motors than what I see on ours, pressure runs between 40.9 high, low 16.8.  I never let the motor spin higher that 2100 rpm.

And after reading some of the posts regarding recent error codes.  I checked ours for codes today after returning from a 300 mile trip.  I have not seen any codes prior but when I checked today, up came code 71 or a ignition key fault.  I did not have any starting problems or while on the road.

Any thoughts?  And is there a way for me to clear it, to see if it returns?

Thank you in advance, I have enjoy your comments and have learned much from all the Forum members.

Regards,

Bill
Regards,

Bill Borden
2000 Patriot Thunder
C-12 425 hp 
Cool, California

Dave Atherton

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Re: Code 71 and a request to Dave Atherton for C12 Test information
« Reply #1 on: August 31, 2015, 10:28:06 PM »
Bill Bordon, the Code 71 your getting is,  43-02 Ignition Key Switch Fault (71 ) here is what is happening.

A 43-02 Ignition Key Switch Fault (71) may occur when the ignition key switch is toggled repeatedly
within a short time peroid. For diagnostic purposes, the engine control module ( ECM ) monitors the
key switch circuit for intermittent connections. Some normal operating conditions may cause the 43-02
Ignition Key Switch Fault to be logged. Some electronic control modules on the vehicle require the quick
cycling of the ignition key switch as a method of requesting diagnostic information. The problem is most
likely that someone has rapidly cycled the ignition key switch in order to prompt diagnostic codes from
vechicle control module.
Do not replace the ECM and do not spend excessive time attempting any diagnostic or repairing the cause
of the logged diagnostic codes. Codes generated due to cycling of ignition key switch will not cause problems
with engine preformance. Code will clear in time or have a Cat Tech clear the code.

The Question Oil pressure is higher than your C-12. there are ( 3 ) ways for engine testing, Spec's
Nominal: High Oil Pressure 49.3 PSI, Low oil Pressure 15.7 PSI  425 HP  @ 1800 RPM
Ceiling:   High Oil Pressure 87.0 PSI, Low OIL Pressure 87.0 PSI,  429 HP  @1810 RPM
Floor:     High OIl Pressure  36.3 PSI, Low Oil Pressure  10.2 PSI   421 HP @ 1790 RPM
Engine Test:  High Oil Pressure 50.9 PSI, Low Oil Pressure 16,0 PSI, 425 HP @ 1795 RPM
The above means engine at different setting as a shake down, your Oil Pressure Numbers
fall in the above and will vary from engines.  Hope this will answer your questions
Dave Atherton Retired Cat Mechanic
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Bill Borden

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Re: Code 71 and a request to Dave Atherton for C12 Test information
« Reply #2 on: September 01, 2015, 08:16:35 PM »
Thanks Dave,

I appreciate your reply.  So if I turn the key on and off, it could throw up a code 71.  Well, just during the time getting ready to leave, that does happen.  And you have cleared up the high oil question.

Also, thank you for sending me the specs on my C12.  It is nice to be able to review and keep it on file. 

Thanks for all you do, helping out on the forum.

Regards,

Bill
Regards,

Bill Borden
2000 Patriot Thunder
C-12 425 hp 
Cool, California