Fault Code 375: Output Speed

J1939: SA 3 SPN 191 FMI 2, 3, 4, 5, 6, 8, 9, 10, 11, 14, 20, 21, 31

Overview

The Endurant XD Series transmissions are equipped with speed sensors to monitor Input, Countershaft, and Output speeds. The speed sensors provide rotational speed inputs to the Transmission Control Module (TCM) for the purpose of verifying clutch engagement, making shift decisions, and confirming gear engagements. The Output Speed Sensor measures the rotational speed and direction of the Planetary Output Shaft Assembly. The Output Speed Sensor is mounted externally on the rear of the transmission and connects to a 3-Way connector on the side of the Mechatronic Transmission Module (MTM). The 3-Way connector is connected to the Transmission Control Module (TCM) at the 74-Way Transmission Harness Connector.

Detection

The TCM monitors the Output Speed Sensor signal. If a system failure is detected, the fault is set Active.

Conditions to Set Fault Code Active

FMI 2 – Data Erratic: Output Speed Sensor signal out of range for 5 seconds.

FMI 3 – Voltage Above Normal or Shorted High: Output Speed Sensor circuit shorted to power for 5 seconds.

FMI 4 – Voltage Below Normal or Shorted Low: Output Speed Sensor circuit shorted to ground for 5 seconds.

FMI 5 – Current Below Normal or Open Circuit: Output Speed Sensor circuit open or shorted to power for 5 seconds.

FMI 6 - Current Above Normal or Grounded Circuit: Output Speed Sensor circuit supply voltage out of normal operating range (4.75V to 5.25V) for 5 seconds.

FMI 8 – Abnormal Frequency: Output Speed Sensor signal out of normal operating frequency for 5 seconds.

FMI 9 – Abnormal Update Rate: Output Speed Sensor signal frequency out of range for 5 seconds.

FMI 10 – Abnormal Rate of Change: Output Speed Sensor signal rate of change exceeded for 2 seconds.

FMI 11 – Root Cause Unknown: Output Speed value above 1 RPM when known countershaft and J1939 Front Axle speeds indicated 0 RPM for 5 seconds.

FMI 14 – Special Instructions: Output Speed value out of range (near 0 RPM) when compared to calculated output speeds based on known Input, Countershaft, and J1939 Front Axle speeds and gear ratio, for 5 seconds.

FMI 20 – Data Drifted High: Output Speed value greater than expected when compared to calculated output speeds based on known Input, Countershaft, and J1939 Front Axle speeds and gear ratio, for 2 seconds.

FMI 21 – Data Drifted Low: Output Speed value less than expected when compared to calculated output speeds based on known Input, Countershaft, and J1939 Front Axle speeds and gear ratio, for 2 seconds.

FMI 31 – Condition Exists: Output Speed value out of range (near 0 RPM) when compared to calculated output speeds based on known Input, Countershaft, and J1939 Front Axle speeds and gear ratio, for 2 seconds.

Fallback

All FMIs

  • Amber warning lamp on
  • If vehicle is moving - Red stop lamp on
  • If Fault Code 375 and 170 are both Active and transmission is in gear:
    • Coast Mode and Neutral Coast prohibited
    • Urge to Move and Creep Mode prohibited
    • Inertia Brake activation prohibited
    • Upshifts prohibited
    • Clutch engagements prohibited
    • Non-Neutral modes prohibited
    • PTO Mode prohibited
  • If Fault Code 375 and 170 are both Active and transmission is not in gear:
    • Urge to Move and Creep Mode prohibited
    • Inertia Brake activation prohibited
    • Non-Neutral modes prohibited
    • PTO Mode prohibited

Conditions to Set Fault Code Inactive

FMI 2: Output Speed Sensor signal in range for 10 seconds.

FMI 3: Output Speed Sensor circuit not shorted to power for 10 seconds.

FMI 4: Output Speed Sensor circuit not shorted to ground for 10 seconds.

FMI 5: Output Speed Sensor circuit not open or shorted to power for 10 seconds.

FMI 6: Output Speed Sensor circuit supply voltage between 4.75V and 5.25V for 10 seconds.

FMI 8: Output Speed Sensor signal frequency in range for 10 seconds.

FMI 9: Output Speed Sensor speed direction known for 10 seconds.

FMI 10: Output Speed Sensor signal rate of change in range for 10 seconds.

FMI 11, 14, 20, 21, 31: Output Speed Sensor signal matches calculated output speeds for 10 seconds.

Possible Causes

FMI 2, 11, 14, 20, 21, 31:

  • MTM - Output Speed Sensor
    • Internal failure
    • Damaged
  • Internal Transmission
    • Mechanical failure
  • TCM
    • Software issue
    • Internal failure

FMI 3:

  • TCM
    • Internal failure

FMI 4, 5, 6, 8, 9, 10:

  • Output Speed Sensor
    • Internal failure
    • Damaged
  • Output Speed Sensor Harness
    • Wiring shorted to power, shorted to ground or open.
  • MTM - Transmission Harness
    • Wiring shorted to power, shorted to ground or open
  • TCM
    • Software issue
    • Internal failure

Additional Tools

  • Endurant XD Service Manual TRSM0960
  • 3-Way Eaton Diagnostic Adapter - RR1060TR
  • Eaton Breakout Box with 74-Way Eaton Diagnostic Adapter - RR1029TR
  • Digital Volt/Ohm Meter (DVOM)

Component Identification

_Graphics/LineArt/TRTS0960_FC375_ComponentID.png

1. Transmission Control Module (TCM) Cover

2. Transmission Control Module (TCM)

3. 74-Way Transmission Harness Connector (TCM-side)

4. 74-Way Transmission Harness Connector (MTM-side)

5. Transmission Control Module (TCM) Seal

6. 3-Way Output Speed Sensor

7. 3-Way Output Speed Sensor Connector

Fault Code 375 Troubleshooting

A
Purpose:Check for active or inactive fault codes.
  1. Set vehicle parking brake and chock wheels.

  2. Record transmission fault codes, FMIs, occurrences, and timestamps from Service Activity Report created during the Diagnostic Procedure.

  • If Fault Code 375 FMI 3 is Active or Inactive, Go to Step E

  • If Fault Code 375 FMI 2, 4, 5, 6, 8, 9, 10, 11, 14, 20, 21, 31 is Active or Inactive, Go to Step B

B
Purpose:Verify condition of 3-Way Output Speed Sensor Connector and power supply.
  1. Key off.

  2. Disconnect the 3-Way Output Speed Sensor Connector at the MTM by lifting up on the yellow latch.

  3. Verify the connector is free from contamination and corrosion; the terminals are not bent, spread or loose; and there is no damage to the connector body.

  4. Connect the 3-Way Eaton Diagnostic Adapter (EDA) to the 3-Way Output Speed Sensor Connector at the MTM.

  5. Key on.

  6. Measure voltage at the 3-Way EDA between Pin 2 (signal) and Pin 3 (5V). Record reading in table.

    _Graphics/LineArt/TRTS0950_FC215_DVOM2and3.png
  7. Compare reading(s) in table.

Ignition StatePinsRangeReading(s)
Key on2 to 34.75–5.25 V
C
Purpose:Verify condition of TCM 74-Way Connector.
  1. Key off.

  2. Remove TCM from MTM with 20-Way TCM Vehicle Harness Connector and 20-Way TCM Body Harness Connector connected.

    _Graphics/LineArt/TRTS0950_FC511_Check74WayTCM.png
  3. Inspect TCM side of the 74-Way Transmission Harness Connector, verify connector is free from contamination and corrosion; terminals are not bent, spread or loose; and there is no damage to connector body.

  4. Inspect TCM Seal, verify seal is properly installed and not damaged.

D
Purpose:Verify Output Speed Sensor power supply at TCM.
  1. Key off.

  2. Connect Eaton Breakout Box with 74-Way Eaton Diagnostic Adapter to TCM 74-Way Connector.

    _Graphics/LineArt/TRTS0950_BreakoutBoxtoTCM.png
  3. Key on.

  4. Measure voltage at Eaton Breakout Box between Pin 52 and Pin 64. Record reading in table.

    _Graphics/LineArt/TRTS0950_FC215_DVOM52and64v.png
  5. Compare reading(s) in table.

Ignition StatePinsRangeReading(s)
Key on52 to 644.75–5.25 V
E
Purpose:Check for active or inactive fault codes.
  1. Confirm a Service Activity Report was downloaded and sent to Eaton.

  2. Retrieve and record the transmission fault codes and FMI’s, and their occurrences and timestamps.

V
Purpose:Verify repair.
  1. Key off.

  2. Reconnect all connectors and verify all components are properly installed.

  3. Key on with engine off.

  4. Connect ServiceRanger.

  5. Go To “Fault Codes”.

  6. Select “Clear All Faults”.

  7. Operate vehicle and attempt to reset the fault code or duplicate the previous complaint.

  8. Check for fault codes using ServiceRanger.

  • If no fault codes set and vehicle operates properly, test complete.

  • If Fault Code 375 sets Active, contact Eaton Cummins Automated Transmission Technologies at +1 800-826-4357 for further diagnostic instructions.

  • If a fault code other than 375 sets Active, troubleshoot per Fault Code Isolation Procedure Index.