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Intake Manifold 1 Pressure – Data Valid but Below Normal Operating Range – Moderately Severe Level
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Overview
| CODE | REASON | EFFECT |
| Fault Code: 125 PID: 102 SPN: 102 FMI: 0/16 LAMP: Amber SRT: |
Intake Manifold 1 Pressure – Data Valid but Below Normal Operating Range – Moderately Severe Level. Intake manifold pressure is below the minimum operating limit. |
Engine power derate. |
 Intake Manifold 1 Pressure/Temperature Sensor Circuit
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Circuit Description
The 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.
If the ECM detects that the necessary charge flow into the engine is below the minimum limits for a period of time, this fault code is logged.
Component Location
The intake manifold 1 pressure/temperature sensor is located in the air intake horn. Refer to Procedure 100-002 in Section E.
Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine is operating.
Conditions for Setting the Fault Codes
The ECM detects that the intake manifold pressure signal reading is below the expected level for the present engine operating conditions.
Action Taken When the Fault Code is Active
The ECM will set the fault code active immediately after the diagnostic is set.
Conditions for Clearing the Fault Code
The fault code will be set inactive when the intake manifold pressure is reading within the normal operating limits.
Shop Talk
Verify the ECM calibration is correct. Check the calibration revision history found on QuickServe™ Online for applicable fixes to the calibration stored in the ECM. If necessary, calibrate the ECM. Refer to Procedure 019-032 in Section 19.
The intake manifold 1 pressure sensor monitors pressure in the intake manifold. This fault is set active when the intake manifold pressure is too low for the present engine operating conditions. The ECM commands a charge flow command and the VGT and EGR valve move to meet this command. If the engine is unable to achieve the desired oxygen level necessary for complete combustion, this fault code is logged.
Possible causes of this fault are:
- Leaks in the air intake system between the turbocharger and intake manifold
- A damaged intake manifold pressure sensor
- A damaged barometric pressure sensor
- Restriction in the charge-air cooler
- Fuel inlet restriction too high. Normally caused by a restricted fuel filter.
- Restriction in the exhaust gas pressure sensing line.
Refer to Troubleshooting Fault Code t05-125
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