6.7L Cummins Forum

I was reading that it is possible to disable the OBDII monitoring system when using a PTO system to prevent false illumination of the CEL. So I was thinking, if the OBD II system just happened to be disabled by using a permanent signal, not just on PTO operation, but during all times of engine operation, would it be possible to unplug the EGR and not get the CEL? Has anybody looked into this?

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2008 Dodge Ram 3500 SLT QCLB SRW 4X4 6.7L Cummins Turbo Diesel 6 Spd Manual

I would like to see the links to the references you read this on. Sound interesting and I would like to read more about it ! ODBII is a diagnostic and reporting subsystem of the on-board computer. Its not a separate device that can be disable and the main computer still runs. However I can see where a trigger is set that causes it to ignore everything .... Very interesting ....

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Straight from the Dodge Bodybuilder website:

PTO and ODB II monitoring systems

2008 Dodge Ram trucks, except 3.7L powertrain options, has a provision that allows ODB II monitoring systems to be disabled while the PTO is being operated. This will prevent "false" lighting of the "Check Engine" lamp due to the engine-PTO driven accessories.

For gasoline applications, ODB II monitoring is disabled by applying a 12-volt ignition feed to circuit G113. This circuit is provided in the engine harness as a "splice" point at the left hand, rear corner of the engine. Approximately five inches of an orange 18 gauge is folded back and taped. To aid in identification, a white plastic tag is attached to the wire and is labeled "PTO".

For diesel applications, the PTO circuit needs to be installed from the power train control module (located on the lower driver side of the engine) pin 38 of the 50 position connector to the PTO device. See your dealership for the proper terminal part number. To disable ODB II monitoring, a ground level signal needs to be applied to this circuit.

http://www.dodge.com/bodybuilder/2008/docs/dr/rcn.pdf - Bottom of page one, top of page two.

So what is a ground level signal?

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2008 Dodge Ram 3500 SLT QCLB SRW 4X4 6.7L Cummins Turbo Diesel 6 Spd Manual

Thanks for the link and very interesting !! Ground level signal is zero and common to all other circuit grounds.

Grounding pin #38 (via a switch) turns off ODBII monitoring .... Can not be that simple .... Really cool if does

Next time I am under the dash, will have to look at it !

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