6.7L Engine Issue, Chassis Cab Only

[HBarlow]

Well, I guess I shouldn't have reported last week that my truck had 20,000 troublefree miles on it.

Last Thursday morning I had my son-in-law's new Haulmark Car Hauler trailer hooked up and was leaving town when I got a chime and a check engine light. No messages were displayed in the EVIC, the truck started and ran normal, gauges all read normal, coolant and oil levels were normal, fuel filter was fresh, and the air filter was clean. I was on my way to Charlotte, NC to pick up a vintage Corvette my s-i-l had just bought on eBay and time was critical so I decided to go anyway.

I ran the truck hard for five days, almost 3,000 miles pulling an empty trailer outbound and a loaded trailer inbound without incident.

This a.m. I took the truck to a local Dodge dealer and reported the problem.

This afternoon about 2:30 the service writer called and said the problem was a P0191 code which identified an intake temperature sensor error.

About 4:30, after I picked my wife up from work in her car that I had borrowed, I stopped by the dealer to check on the truck. My truck repair had made a sharp left turn this afternoon after the service writer called.

The bottom line is the truck is not repaired, is not currently repairable, and may be or may not be repaired in October. It is, however, driveable and drives completely normally.

After interpreting the P0191 code earlier today as an intake temp sensor error and notifying me, the tech apparently learned that was not correct.

When I stopped by this afternoon to check on the truck the service writer said the tech learned later that a P0191 means intake sensor on a pickup, but has a different meaning on a chassis cab. I don't know if this is correct or not but, if true, sounds like a bad idea. He explained that a P0191 code in a chassis cab means fuel pressure error or fuel pressure sensor error.

He gave me a printed page from their computer which reads:

"Part Number 68002436AB"
"Part Description: Sensor, Fuel Rail Pressure"

"2007/2008 Ram 3500 Chassis Cab and Ram 4500/5500 with a 6.7L Cummins diesel: If ordering this sensor for a P0191 fault, please be aware that in the majority of cases this fault is being driven (in error) by the engine software, not a faulty sensor. We are working on a software update to correct the issue and will release the software via a TSB. TSB release is tentatively targeted for October 2008. Contact xxxxx xxxxxx of Cummins at: (xxx) xxx-xxxx if you have further questions." (Name and number deleted by me)

The tech said he measured fuel pressure and it is normal and thinks the sensor is okay, the software just thinks it is not. He couldn't explain why this suddenly occurred at 20,000+ miles.

The tech attempted to clear the fault code but it immediately returns and remains on. So, I guess I'll keep driving it and waiting for a software update which I probably don't want because it may involve unwanted fuel curve changes. I hope not. The tech told me this morning he was not aware of any TSB software changes for 2008 C&Cs when I told him I didn't want any reflashes.

The tech told me today, without sounding certain, that when a fault code is set, the engine does not regen and advised me to watch the EVIC for a warning that the DPF is becoming full. He says if this happens return the truck and he will do a forced regen.

This event today makes me wonder why Cummins refused to answer a regen question several months ago but told me to ask Dodge. Based on the message quoted above I am less convinced that Dodge is responsible for the engine software and components. I asked the tech today and he did not know who makes and is responsible for the software but clearly, from the message I quoted above, it appears Cummins is.

I did learn one useful thing today. It IS possible to read out the codes in the odometer of '08 trucks. It is done by turning the key on and off three times rapidly without pause. Some have reported that it can't be done on new trucks. I watched the tech do it repeatedly.

Do any Dodge technician/TDR members have anything to contribute to a broader understanding of this issue?