Baffling problem with a '97 Cummins M11

clavin transport · Mar 19, 2013

I had the same problem and fixed it today with a new pressure sensor located on the head by the firewall..passenger side of the valve cover...where the fuel tubes go into the head. there is two sensors, one slightly larger and closer to the firewall is the one I changed....all power came back, I have a '95 cummins M-11... hope it helps

clavin transport · Mar 19, 2013

Now I need to know what it means when my computer reads "reserved 500" and check engine light came on....500 miles after the first fix. When I shut the engine off and turned it back on it went out...

San Diego tds · Dec 22, 2016

Heavyd said: ↑

SAE fault 102 - 2 for a M11 is for the intake manifold pressure circuit. The Cummins fault code number is 433. SAE codes get mis-read all the time. Like Bender said the actual code should be retrieved using Insite to get the actual Cummins code. I also don't like the code description it is telling you and that may be leading you astray. If it is 433, this means the ECM is reading boost pressure that is higher than it thinks is physically possible given the current engine operating characteristics. The ECM will only log this code at idle. When the ECM logs this code it will derate to the "No air" setting, or basically no or low boost. There is not thing wrong with your turbo, or air to air. Your boost gauge is only a mechanical gauge reading actual manifold pressure. Your boost is low because the ECM is cutting back power until the 433 code becomes inactive. This is usually an electrical problem with intake manifold pressure sensor or related wiring. You said you replaced the sensor in the turbo. This makes no sense as there are no sensors in the turbos. The intake manifold pressure sensor is located at the back of the intake manifold. It should be a 3 wire sensor. Is this the sensor you are talking about? Your truck is 15 years old, the engine wiring could also be the problem. Wiring gets brittle over time, rubs through, and shorts out. You also need to thoroughly inspect the wiring and the terminals inside the connectors for any bend or worn pins. Also look for corrosion. All these will send false signals. The intake pressure sensor is supplied with 5 volts, and a return circuit that is also shared by the oil pressure sensor, ambient air pressure sensor and the coolant level sensor. If any of these other sensors are shorting out it could also be causing this problem and not necessarily causing a fault of their own.
Click to expand...

I have the same problem , did you found how to fix it ?

San Diego tds · Dec 22, 2016

Heavyd said: ↑

SAE fault 102 - 2 for a M11 is for the intake manifold pressure circuit. The Cummins fault code number is 433. SAE codes get mis-read all the time. Like Bender said the actual code should be retrieved using Insite to get the actual Cummins code. I also don't like the code description it is telling you and that may be leading you astray. If it is 433, this means the ECM is reading boost pressure that is higher than it thinks is physically possible given the current engine operating characteristics. The ECM will only log this code at idle. When the ECM logs this code it will derate to the "No air" setting, or basically no or low boost. There is not thing wrong with your turbo, or air to air. Your boost gauge is only a mechanical gauge reading actual manifold pressure. Your boost is low because the ECM is cutting back power until the 433 code becomes inactive. This is usually an electrical problem with intake manifold pressure sensor or related wiring. You said you replaced the sensor in the turbo. This makes no sense as there are no sensors in the turbos. The intake manifold pressure sensor is located at the back of the intake manifold. It should be a 3 wire sensor. Is this the sensor you are talking about? Your truck is 15 years old, the engine wiring could also be the problem. Wiring gets brittle over time, rubs through, and shorts out. You also need to thoroughly inspect the wiring and the terminals inside the connectors for any bend or worn pins. Also look for corrosion. All these will send false signals. The intake pressure sensor is supplied with 5 volts, and a return circuit that is also shared by the oil pressure sensor, ambient air pressure sensor and the coolant level sensor. If any of these other sensors are shorting out it could also be causing this problem and not necessarily causing a fault of their own.
Click to expand...

Did you found the problem ? please let me know . I have the same problem , thanks

tony97905 · Dec 25, 2016

Like HD stated, the first thing I would look at is the engine harness on these older engines. Without being able to monitor ecm readings you will "flying blind" looking for cut/chafed wires within the harness.

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