SureTrack Real Fix: RAM Shutdown Unlocked

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Real Fixes from SureTrack® provides expert-based knowledge captured from millions of documented repairs and community discussions. Read on to see how SureTrack can help you fix tricky issues that are not easily diagnosed with OEM information alone. SureTrack is available at no additional cost within ProDemand.

This fix illustrates the power of the SureTrack community to quickly help a fellow tech solve a problem. SureTrack community member, Emmer, had a 2014 RAM 1500 SLT in the shop after recent replacements of the lifters and camshaft. Now, the vehicle is experiencing an MDS #1 cylinder shutdown. They posed the question to the community, and with the help of ericsautomotive and Skip, they were able to resolve the issue quickly.

The following Community Fix summarizes the interaction between members of the community that led to the solution.

Vehicle
2014 RAM 1500 SLT 5.7L Eng VIN T

Title
MDS Cylinder #1 Shutdown at Idle

Complaint
The diagnostic scanner shows MDS #1 shutdown is always active and code P1411 is set.

Diagnostic Steps Performed/Parts Replaced
About 4 months ago I replaced all the lifters and camshaft as a lifter roller had failed and it ate into the camshaft. Worked perfectly for 4 months, but now the issue has appeared. KOEO, test cycled all 4 MDS solenoids and listened for clicking, all could be heard clicking when turned on and off. Pulled intake and inspected harness, all look good, tested MDS #1 and reads 9 Ohms at about 20Deg. Tested harness between PCM and Solenoid, no shorts or opens. Pulled valve cover and inspected rockers and springs, all looked good, with no broken springs. Had a good Used MDS solenoid on hand, replaced the #1, and reassembled, but same issue. Back probed the MDS #1 pin on the PCM while running and it showed powered while the engine was idling, the other MDS were unpowered. With KOEO it is unpowered. Pulled the pin to MDS #1 at the PCM to take the power away and a slight tick could be heard from the #1 cylinder area, Bridged the power back and the tick went away.

Cause
The lock pin in the MDS lifter was not locking in and returning the lifter to normal operation, when the lifter was removed it was visible that the pin was not locked in or even visible. After the repair, the PCM removed power to the solenoid on its own. Even though there is nothing in the diagram that I can find, on this particular truck the PCM when detecting a failure to disengage the MDS on a cylinder, will lock that cylinder out electronically to prevent excessive clearance in the valve train.

Correction
Replaced the MDS lifter, allowing oil pressure from the solenoid to push the locking pin in place and free the lifter to collapse and regulate pressure to the valves.

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About the Author

Abagail Lucero

Abagail Lucero is the Product Marketing Manager for ProDemand. She joined the company in 2011 as a member of the SocialCRM shop marketing team and has served in many roles at Mitchell1, lastly as Security and Compliance Supervisor. Abagail holds a Bachelor of Science degree from California University of Pennsylvania.