Cummins X12 CM2350 Fault Code 1894 |SPN 641 |FMI 9/9 |PID S27

Uncategorized

FAULT CODE 1894

VGT Actuator Driver Circuit – Abnormal Update Rate

Overview

 

CODE REASON EFFECT
Fault Code: 1894
PID: S27
SPN: 641
FMI: 9/9
LAMP: Amber
SRT: 

 

No communications on the J1939 data link between the engine ECM and the smart VGT controller.

 

 

Possible reduced engine performance.

 
VGT Actuator Circuit

Circuit Description

The variable geometry turbocharger (VGT) is electronically activated by the VGT actuator. The VGT actuator is a smart device and receives information via the J1939 data link from the primary engine control module (ECM). The VGT actuator performs its own diagnostics and reports malfunctions back to the primary engine ECM, using the J1939 data link. The ECM then decodes the error message and converts it to a fault code.

Component Location

The VGT actuator is located on the turbocharger bearing housing.

 

Conditions for Running the Diagnostics

This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes

The Engine Control Module (ECM) did not receive a valid J1939 data link message from the Variable Geometry Turbocharger (VGT) actuator for more than 1 second.

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.
  • VGT actuation will be disabled.
  • 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, perform a key cycle, start the engine and let it idle for 1 minute.
  • 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.
  • For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where 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

Possible causes of this fault code include:

  • A weak or damaged battery.
  • Battery connections are loose or dirty.
  • Malfunctioning or damaged fuse.
  • Malfunctioning or damaged aftertreatment power relay.
  • Malfunctioning or damaged OEM wiring harness.
  • Malfunctioning or damaged engine wiring harness
  • Malfunctioning or damaged datalink terminating resistors.
  • Malfunctioning or damaged J1939 data link component.

Troubleshooting Summary

  1. Check for primary fault codes
  2. Multiple Technical Service Bulletins are available
  3. Low battery voltage
  4. Battery load test
  5. Ground inspection
  6. Variable geometry turbocharger actuator voltage check
  7. Variable geometry turbocharger actuator voltage check at the ECM
  8. Circuit Load Test
  9. Fault Code 1894 triggered by a malfunction in the J1939 data link with multiple OEM fault codes
  10. Variable geometry turbocharger actuator has incorrect J1939 terminating resistance
  11. J1939 data link terminating resistance is incorrect
  12. Variable geometry turbocharger actuator has incorrect J1939 terminating resistance
  13. Engine wiring harness has incorrect J1939 terminating resistance
  14. OEM wiring harness has incorrect J1939 terminating resistance
  15. ECM calibration revision history check

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:

  • Turbocharger: 1897,1962,1976
  • Voltage: 1941

Linked Solutions

  • None

Repair

  • Perform a search on the appropriate fault codes.

Validation

  • None

Verification

Conditions

  • Turn keyswitch OFF.

Action

Only refer to the technical service bulletins for the fault codes being diagnosed.

All of the technical service bulletins listed may not apply to your application. Refer to the list of affected products in each technical service bulletin.

  • Technical Service Bulletin is available for the following fault codes: 2771, 3232
  • Technical Service Bulletin is available for the following fault codes: 3868, 4572, 4677
  • Technical Service Bulletin is available for the following fault codes: 3868, 4277, 4572, 4677
  • Technical Service Bulletin is available for the following fault codes: 1894, 2771, 3232, 3868, 3911, 4151, 4152, 4572, 4677, 5177, 6688
  • If this engine is not in a PACCAR™ application, then proceed to the next solution.
  • Technical Service Bulletin is available for the following fault codes: 3868, 4572, 4677
  • If this engine is not in a Navistar application, then proceed to the next solution.
  • Technical Service Bulletin is available for the following fault codes: 4277

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.

Verification

Conditions

  • Turn keyswitch OFF.

Action

  • Visually inspect the batteries and the battery cable connections for corrosion.
  • Measure the voltage from the positive (+) battery terminal to the negative (-) battery terminal.
  • If this vehicle has been repaired within the last 30 days for the same fault code, then proceed to the Linked Solutions section.

Specification

  • If the battery voltage is at least 10.8 VDC (12 volt systems) or 21.6 VDC (24 volt systems), then proceed to the Linked Solutions section.
  • If the battery voltage is below 10.8 VDC (12 volt systems) or 21.6 VDC (24 volt systems), then proceed to the Repair section.
  • If the battery or battery cables show signs of corrosion or damage, then proceed to the Repair Section.

Linked Solutions

  • Battery load test
  • Ground inspection

Repair

Repair or replace only the components that were found to be out of specification.

  • Charge or replace the batteries.

Refer to OEM Service Manual

  • Clean corrosion or tighten battery cable connections.

Refer to OEM Service Manual

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.

Verification

Conditions

  • Turn keyswitch OFF.

Action

  • Disconnect the batteries from each other.
  • Connect a load tester separately to each battery.
  • Measure the voltage from the positive (+) battery terminal to the negative (-) battery terminal.

Specification

  • For a 12 volt system, proceed to the Repair section if the battery voltage is below the following specification: 11 VDC
  • For a 24 volt system, proceed to the Repair section if the battery voltage is below the following specification: 22 VDC

Linked Solutions

  • None

Repair

  • Charge or replace the batteries.

Refer to OEM Service Manual

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.

Verification

Conditions

  • Turn keyswitch OFF.

Action

  • Visually inspect the ECM ground for damage, corrosion and loose connections.
  • Visually inspect the aftertreatment interface wiring harness ground for damage, corrosion and loose connections.
  • Visually inspect the OEM wiring harness ground for damage, corrosion and loose connections.
  • Visually inspect the grounds for proper routing.

Specification

  • If damage, corrosion or incorrect routing of grounds are found, then proceed to the Repair section

Linked Solutions

  • None

Repair

  • Clean or replace connections.

Refer to OEM Service Manual

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.

Verification

Conditions

  • Turn keyswitch OFF.
  • Disconnect the variable geometry turbocharger actuator from the engine wiring harness.

Action

  • Inspect the pins and connectors for damage.
  • Turn keyswitch ON.
  • Measure the voltage between the variable geometry turbocharger actuator battery SUPPLY pin and the variable geometry turbocharger actuator battery RETURN pin at the variable geometry turbocharger actuator engine wiring harness connector.
  • Refer to the circuit diagram or wiring diagram for connector pin identification.

Specification

  • Proceed to the Linked Solutions section and perform the voltage check at the ECM if voltage is not within the following specification: 1 VDC

Linked Solutions

  • Variable geometry turbocharger actuator voltage check at the ECM

Repair

  • No additional action is required for this solution.

Validation

  • None

Verification

Conditions

  • Turn keyswitch OFF.
  • Disconnect the engine wiring harness connector from the ECM.

Action

  • Inspect the pins and connectors for damage.
  • Turn keyswitch ON.
  • Measure the voltage between the variable geometry turbocharger actuator battery SUPPLY pin and the variable geometry turbocharger actuator battery RETURN pin at the ECM.
  • Refer to the circuit diagram or wiring diagram for connector pin identification.

Specification

  • A malfunctioning engine wiring harness has been detected if the voltage is within the following specification of battery voltage: 1 VDC
  • A malfunctioning ECM has been detected if the voltage is not within the following specification of battery voltage: 1 VDC

Linked Solutions

  • None

Repair

Repair or replace only the components that were found to be out of specification.

  • Repair or replace the engine wiring harness.
  • Replace the ECM.

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.

Verification

Conditions

  • Turn keyswitch OFF.
  • Disconnect all components on the wiring circuit being tested.

Action

This test is NOT for checking the J1939 data link (+) and (-) pins since it may cause damage to the J1939 smart devices or sensors.

This test is NOT for checking the OEM wiring harness since it may cause damage to OEM smart devices or sensors.

  • Perform the Circuit Load Test for the circuit being tested.
  • Refer to the circuit diagram or wiring diagram for connector pin identification.

Specification

  • If the voltage drop is not within specification, then a malfunctioning wiring harness has been detected.

Linked Solutions

  • None

Repair

Repair or replace only the components that were found to be out of specification.

  • Repair or replace the engine wiring harness.
  • Repair or replace the OEM wiring harness.

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.

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.

Specification

  • Proceed to the Linked Solutions section if a fault code from the following list is not active or does not have more than one inactive count within the last 25 engine operating hours: 2771, 3232, 3868, 3911, 4151, 4152, 4572, 4677, 6688

Linked Solutions

  • Variable geometry turbocharger actuator has incorrect J1939 terminating resistance
  • If the above checks are all within specification, then proceed to the Repair section.

Repair

  • Refer to your technical escalation process.

Validation

  • None

Verification

Conditions

  • Turn keyswitch OFF.
  • Disconnect the variable geometry turbocharger actuator from the engine wiring harness.

Action

  • Inspect the pins and connectors for damage.
  • Measure the resistance between the variable geometry turbocharger actuator SAE J1939 data link (+) pin and the variable geometry turbocharger actuator SAE J1939 data link (-) pin at the variable geometry turbocharger actuator.
  • Refer to the circuit diagram or wiring diagram for connector pin identification.

Specification

  • A malfunctioning variable geometry turbocharger actuator has been detected if the resistance is not within the following specification: 108 Ω – 132 Ω

Linked Solutions

  • None

Repair

  • Replace the variable geometry turbocharger actuator.

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.

Verification

Conditions

  • Turn keyswitch OFF.
  • Wait for 90 seconds.
  • Disconnect the INLINE adapter from the 3-pin service data link connector.
  • Reconnect the variable geometry turbocharger actuator if it has been previously disconnected.

Action

  • Inspect the pins and connectors for damage.
  • Measure the resistance between the SAE J1939 data link (+) pin and the SAE J1939 data link (-) pin at the 3-pin service data link connector.

Refer to Procedure 019-417

  • Refer to the circuit diagram or wiring diagram for connector pin identification.

Specification

  • Follow your technical escalation process if the resistance is within the following specification: 54 – 66 Ω
  • Proceed to the Linked Solutions section if the resistance is not within the following specification: 54 – 66 Ω

Linked Solutions

  • Variable geometry turbocharger actuator has incorrect J1939 terminating resistance
  • Engine wiring harness has incorrect J1939 terminating resistance
  • OEM wiring harness has incorrect J1939 terminating resistance

Repair

  • No additional action is required for this solution.

Validation

  • None

Verification

Conditions

  • Turn keyswitch OFF.
  • Disconnect the variable geometry turbocharger actuator from the engine wiring harness.

Action

  • Inspect the pins and connectors for damage.
  • Measure the resistance between the variable geometry turbocharger actuator SAE J1939 data link (+) pin and the variable geometry turbocharger actuator SAE J1939 data link (-) pin at the variable geometry turbocharger actuator.
  • Refer to the circuit diagram or wiring diagram for connector pin identification.

Specification

  • A malfunctioning variable geometry turbocharger actuator has been detected if the resistance is not within the following specification: 108 Ω – 132 Ω

Linked Solutions

  • None

Repair

  • Replace the variable geometry turbocharger actuator.

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.

Verification

Conditions

  • Turn keyswitch OFF.
  • Reconnect previously disconnected components.
  • Disconnect the INLINE adapter from the 3-pin service data link connector.
  • Disconnect the aftertreatment intake NOx sensor from the engine wiring harness.
  • Disconnect the engine wiring harness from the OEM wiring harness crossover connector.

Action

  • Inspect the pins and connectors for damage.
  • Measure the resistance between the SAE J1939 data link (+) pin and the SAE J1939 data link (-) pin at the 3-pin service data link connector.
  • Refer to the circuit diagram or wiring diagram for connector pin identification.

Specification

  • A malfunctioning engine wiring harness has been detected if the resistance is not within the following specification: 108-132 Ω

Linked Solutions

  • None

Repair

  • Repair or replace the engine wiring harness.

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.

Verification

Conditions

  • Turn keyswitch OFF.
  • Disconnect the engine wiring harness from the OEM wiring harness crossover connector.

Action

  • Inspect the pins and connectors for damage.
  • Measure the resistance between the SAE J1939 data link (+) pin and the SAE J1939 data link (-) pin at the crossover of the OEM wiring harness connector.
  • Refer to the circuit diagram or wiring diagram for connector pin identification.

Specification

  • Proceed to the next solution if the resistance is not within the following specification: 108 – 132 Ω
  • Follow your technical escalation process if the resistance is within the following specification: 108 – 132 Ω

Linked Solutions

  • None

Repair

  • No additional action is required for this solution.

Validation

  • None

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.