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2021 Ram 1500 MDS Sensor Failure

Miketc31

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Hello all,

Well it started out as a simple oil change and tire rotation. Started driving and noticed my check engine light had turned on. From what the shop said, it a MDS sensor in cylinder 1 that is shot. I did notice the tuck did not enter the ECO mode anymore.

I have been trying to read ip on this issue and it does not seem like an uncommon issue. I was possibly looking at getting the sensors replaced, the price is crazy!

I have seen some forums talking about just disabling the MDS. Seen alot suggesting the Pulsar tune.

Wondering if I should just get the Pulsar (cheaper option) to just disable the MDS, or get the sensors replaced?

Thank you in advance!
 

stevj

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While you decide, you can manually turn off 4-cylinder mode this way:
After shifting into DRIVE, use the manual shift buttons on the steering wheel. Press (-) to enable the manual shift gear number display, then press (+) repeatedly until numerical display to right of current gear shows 8.
You have to do this every time you select Drive, but it keeps all 8 cylinders active.

I'm told enabling Tow/Haul will also disable 4-cylinder mode, but have not verified.

Steve
 

HemiDude

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Some specs on your truck might be of some help. The first thing I would do is inspect under the hood to see if something was disconnected or pinched.
 

Scooter4x

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Holley just released the Pulsar XT for Ram pickups, it does not require a new PCM and installs inline under the dash and removes the need to shift the gear into 8. Mine is arriving today and will install tomorrow. Will update with results.
 

HemiDude

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Holley just released the Pulsar XT for Ram pickups, it does not require a new PCM and installs inline under the dash and removes the need to shift the gear into 8. Mine is arriving today and will install tomorrow. Will update with results.
Is that for the diesel?
 

bigdodge

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Holley just released the Pulsar XT for Ram pickups, it does not require a new PCM and installs inline under the dash and removes the need to shift the gear into 8. Mine is arriving today and will install tomorrow. Will update with results.
very interesting
 
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Holley just released the Pulsar XT for Ram pickups, it does not require a new PCM and installs inline under the dash and removes the need to shift the gear into 8. Mine is arriving today and will install tomorrow. Will update with results.
I installed mine today and it gave me two codes P2127 (Pedal Pos Validation Switch 2 Low) and P2122 (Throttle/ Pedal Pos Sens/Switch D Circ Low Input) showed up.
I disconnected the battery, check engine light was gone but it came back again. I made sure the connections were done right but the light is still on.
Let me know please if you get the same.
Thanks!!
 

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