Overview
| CODE | REASON | EFFECT |
| Fault Code: 125 PID: P102 SPN: 102 FMI: 1/18 LAMP: Amber SRT: |
Intake manifold pressure is below the minimum operating limit.
|
Possible reduced engine performance. |
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 1 pressure/temperature sensor is located in the air intake manifold.
Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine is running.
Conditions for Setting the Fault Codes
The Engine Control Module (ECM) detected the intake manifold pressure reading was below the expected level for the engine operating conditions.
Action Taken When the Fault Code is Active
- The ECM illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.
- Exhaust gas recirculation (EGR) valve operation will be disabled.
- Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.
Conditions for Clearing the Fault Code
- To validate the repair, use the recommended Cummins® electronic service tool or equivalent to perform the “Air Handling Performance Test” found in ECM Diagnostic Test.
- The fault code status displayed by the recommended Cummins® electronic service tool or equivalent will change to INACTIVE immediately after the diagnostic runs and passes.
- The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
- The “Reset All Faults” command in the recommended Cummins® electronic service tool or equivalent can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.
Shop Talk
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 code include:
- Leaks in the air intake system between the turbocharger and intake manifold
- A damaged intake manifold pressure sensor
- Malfunctioning or damaged barometric pressure sensor.
- Restriction in the charge-air cooler
- Leaks or restrictions in the EGR system plumbing
- Fuel inlet restriction too high (normally caused by a restricted fuel filter).
Troubleshooting Summary
Solution: S00000794
Verification
Conditions
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
Action
- Use the recommended Cummins® electronic service tool or equivalent to read the fault codes.
Specification
Before troubleshooting this fault code, troubleshoot any fault code that is active or has more than one inactive count within the last 25 engine operating hours from the following list:
- Intake manifold: 122, 123, 2973
- Barometric pressure: 221, 222, 295
- Turbocharger: 629, 687, 2387, 2449, 2634, 2635, 2636, 3348, 3616
- EGR: 1228, 1896, 1898, 2198, 2272, 2349, 2353, 2357
Linked Solutions
- None
Repair
- Perform a search on the appropriate fault codes.
Validation
- None
Solution: S00007879
Verification
Conditions
- Turn keyswitch OFF.
Action
Only refer to the technical service bulletins for the fault codes being diagnosed.
For all applications proceed to the next action.
- Technical Service Bulletin is available for the following fault codes: 1866, 3361, 3382, 3383, 3389, 4729, 7232, 7233
- Technical Service Bulletin is available for the following fault codes: 125, 743, 2191, 2973, 1664, 5989
- Technical Service Bulletin is available for the following fault codes: 7232
If this is a Navistar application, then proceed to the next action.
- Technical Service Bulletin is available for the following fault codes: 125, 1866, 3361, 3382, 3389, 4729
If the engine was operating in cold weather, then proceed to the next action.
- Technical Service Bulletin is available for the following fault codes: 3542
Specification
- Proceed to the Repair section if the Technical Service Bulletin is applicable.
Linked Solutions
- None
Repair
- Complete the action outlined in the Technical Service Bulletin.
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the “Conditions for Clearing the Fault Code” found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
Solution: S00009149
Verification
Conditions
- Reconnect previously disconnected components.
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
Action
- Use the recommended Cummins® electronic service tool or equivalent.
- Perform the Air Handling Performance Test.
Specification
- If the Air Handling Performance Test does not pass, then reset the search to Air Handling Performance Test Did Not Pass. Only select the solution title that matches the error messages in the recommend Cummins® electronic service tool or equivalent.
- If the Air Handling Performance Test will not start, then reset the search to Air Handling Performance Test Did Not Start.
- If the Air Handling Performance Test does not complete, then reset the search to Air Handling Performance Test Did Not Complete.
Linked Solutions
- None
Repair
- No additional action is required for this solution.
Validation
- None
Solution: S00000443
Verification
Conditions
- Connect all components.
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
Action
- Use the recommended Cummins® electronic service tool or equivalent to read the fault codes.
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revision listed in the ECM calibration revision history for applicable changes.
Specification
- If a calibration update for this fault code is available, the ECM calibration revision must be that revision or higher.
Linked Solutions
- None
Repair
- Prior to downloading the ECM calibration, check to see that all job images and all other troubleshooting has been documented as downloading an ECM calibration will remove the fault codes on the ECM.
- Download the updated ECM calibration code.
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the “Conditions for Clearing the Fault Code” found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
If all steps have been completed and no root cause has been identified, then follow the technical escalation process.