Cummins ISB4.5 CM2150 Fault Code: 2973 PID: 106 SPN: 102 FMI: 2 Intake Manifold 1 Pressure – Data Erratic, Intermittent, or Incorrect.

Circuit Description
The engine control module (ECM) provides a 5 volt supply to the intake manifold pressure sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The intake manifold pressure sensor provides a signal to the ECM on the intake manifold pressure sensor signal circuit. This sensor signal voltage changes, based on the pressure in the intake manifold.

Component Location
The intake manifold pressure/temperature 1 sensor is located in the air intake manifold.

The barometric pressure sensor can be externally mounted on the engine or can be an internal component within the ECM. Check engine wiring diagram for circuit details.

Conditions for Running the Diagnostics
This ECM diagnostic runs in two parts consisting of three separate conditions without keying off between steps:

1. Key ON – Part 1 of this diagnostic runs a sensor rationality check when the keyswitch is initially turned on. If the fault code became active at key ON only, it has failed the first check.

2. Operation – Part 2 of this diagnostic will run a pressure rationality check when the engine is running under normal conditions. The diagnostic runs a check at the following conditions:

>1500 rpm at 100 percent load, for 25 non-consecutive seconds.
<2000 rpm while motoring for 25 non-consecutive seconds with a charge-air pressure < 140kPa or 150kPa depending upon the specific ECM calibration. Exhaust brake must be disabled at all times diagnostic will not run. Service tips: -If key ON has malfunctioned, only rationality needs to run. -If fault code became active>1500 rpm and under load, only the >1500 rpm condition needs to be completed.
-If the fault code became active at <2000 rpm while motoring, only the <2000 motoring condition needs to be completed. Check ECM job image and fault code snapshot window in INSITE™ electronic service tool see if flagged engine was running or at key ON. Check load help determine which part malfunctioned. Conditions for Setting Fault Codes This diagnostic checks value of intake manifold pressure sensor ON is running. If not reading ambient higher lower than expected during normal operation, this logged. Action Taken When Code Active -The illuminates MIL immediately when runs fails ONE trip. -A significant de-rate will occur default OFC fuelling tables protect from damage. Conditions Clearing Code -Run as described above. -Once has completed, go inactive it passes. -As soon completed passed one trip, out immediately. inactive, use “clear all faults” command latest version tool. Shop Talk This consists two parts. At ON, before starts, readings pressure, barometric air exhaust gas are compared each other. This occurs different other readings. check done once after keyswitch turned can also set active too high low present operating conditions The compares turbocharger speed valid. Possible Causes -A damaged -Leaks system between -Restriction charge-air cooler compressor temperature wiring harness cause intermittent codes due resistances. diagram shared supply return circuit on sensors. It possible that more could incorrectly a commonground problem exists circuit. Use log any fluctuation voltagevalues moved. NOTE: In guided steps 2973, gauge may need converted absolute depending you troubleshooting. Barometric approximately 29.92 in-Hg sea level. (Absolute Pressure) The 0 (Gauge Pressure) 1 atmosphere = 1.013 bar Example: (Absolute) reads 31 (Gauge) -5 then difference calculated follows: 1. Convert Absolute (-5 + 29) = 24 in-Hg. 2. Subtract new 24 original in-Hg. (31 – 24) ="7 3." 7 greater specification 3 troubleshooting become active. 4. Barometric Pressure Altitude table following procedure understand altitudes.