UltraShift PLUS
TRTS0940 EN-US
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July 2024 - A

Fault Code 41: Range Failed to Engage

J1587: MID 130 SID 35 FMI 7

MID 130 SID 36 FMI 7

J1939: SA 3 SPN 768 FMI 7

SA 3 SPN 769 FMI 7

Overview

Most Heavy-Duty UltraShift PLUS Transmission models are equipped with a 2-speed range system in the auxiliary case. The ability to select an auxiliary range gear independently from a main case gear allows the transmission twice the number of overall gear ratios. Main case gearing can be used once in auxiliary low range and again in auxiliary high range.

The range system is equipped with a Range Solenoid Valve. The Range Solenoid Valve is an electric-over-air solenoid controlled by the Transmission Electronic Control Unit (TECU).

During operation, the solenoid directs air pressure to either port in the Range Cylinder based on the need to activate the auxiliary low range or high range gearing. The applied air pressure directs the fore-and-aft movement of the Range Piston within the Range Cylinder, facilitating the mechanical engagement of the Range Synchronizer into either low or high range. Fault Code 41 indicates the transmission is unable to complete a range shift.

Detection

When toggling the Range Solenoid Valve, the TECU verifies the new range position by calculating the overall transmission gear ratio, using the Main Shaft and Output Shaft Speed Sensor signals. If the calculated ratio does not match the expected ratio for the new range position, the auxiliary case gearing did not change as expected and the TECU sets the fault code Active.

The TECU detected a range system failure, but was unable to detect the specific root cause.

Conditions to Set Fault Code Active

FMI 7 – Mechanical System Not Responding: Transmission is either stuck in its current range position or it cannot engage the desired range position after five consecutive attempts.

Fallback

FMI 7

  • Transmission remains in the range where the failure occurred.
  • Transmission may attempt to shift into low range when the vehicle comes to a stop.
  • Until the fault becomes Inactive, driver may have to shut off engine with transmission in gear.

Conditions to Set Fault Code Inactive

FMI 7: Transmission successfully attains the requested range for 2 seconds.

Possible Causes

FMI 7

  • Vehicle Air System
    • Low vehicle air pressure
    • Contamination in air supply
    • Air leaks
    • Filter-Regulator failure
  • Range Solenoid Valve
    • Mechanical failure
  • Mechanical Transmission
    • Range Synchronizer failure
    • Range Cylinder, Piston or Yoke wear or damage
    • Range Cover Gasket failure
    • Tone Wheel damage
    • Failed auxiliary case components
  • Main Shaft Speed Sensor
    • Internal failure
  • Output Shaft Sensor
    • Internal failure

Additional Tools

  • Two 0–100 PSI Air Pressure Gauges
  • 0–150 PSI Air Pressure Gauge

Component Identification

_Graphics/LineArt/TRTS0940_FC41_ID1.png

1. Range Solenoid Valve (LAS / VAS / MHP / VHP / MXP / LSE / VXP)

2. Range Solenoid Valve (VCS / VMS)

_Graphics/LineArt/TRTS0940_FC41_FC42_ID2.png

1. Range Solenoid Valve (LO)

2. Cylinder Port (Exhaust)

3. Exhaust Port

4. Regulated Port (Air)

5. Shift Yoke

6. Piston

7. Filter-Regulator

8. Range Solenoid Valve (HI)

9. Regulated Port (Air)

10. Cylinder Port (Exhaust)

Fault Code 41 Troubleshooting

A
Purpose:Check for Active or Inactive fault codes.

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

  • If Fault Code 41 FMI 7 is Active or Inactive, go to TAIB-0999 Fault Code 41 and/or 42 Due to a Restricted Range/Splitter Exhaust Port.

  • If Fault Code 41 FMI 7 is Active or Inactive, and Fault Codes 43, 57 or 58 are not set and Range Exhaust Port is not restricted, Go to Step B

B
Purpose:Verify vehicle air supply pressure.

  1. Key off.

  2. Set parking brake and chock wheels.

  3. Vent vehicle air supply tanks.

    Caution
    Vehicle air tanks may have air stored at pressures in excess of 100 PSI. Failure to vent air tanks may cause personal injury.

  4. Install a 0–150 PSI air pressure gauge between the supply line and the air Filter-Regulator located at the back of the transmission.

    _Graphics/LineArt/GaugeSupplyLine.png

  5. Key on with engine running.

  6. Allow air pressure to build to governor cut off.

  7. Key off.

  8. Monitor air pressure at gauge on supply line for 1 minute. Record reading(s) in table.

  9. Compare reading(s) in table.

  • If readings are in range and the vehicle is able to maintain pressure, Go to Step C

  • If readings are out of range, or the vehicle can not hold pressure, repair vehicle air system per OEM guidelines. Go to Step V

ModelPressureReading(s)
All Models90–120 PSI
C
Purpose:Verify Air Filter-Regulator operation.

  1. Key off.

  2. Vent vehicle air supply tanks.

    Caution
    Vehicle air tanks may have air stored at pressures in excess of 100 PSI. Failure to vent air tanks may cause personal injury.

  3. Reconnect the supply line to the Air Filter-Regulator.

  4. Install a 0–100 PSI air pressure gauge into a regulator test port of the Air Filter-Regulator.

    _Graphics/LineArt/RegulatorAirPressureTest.png

  5. Key on with engine running.

  6. Allow air pressure to build to governor cut off.

  7. Key off.

  8. Monitor air pressure and record reading(s) in table.

  9. Compare reading(s) in table.

ModelPressureReading(s)
LAS/VAS75–85 PSI
All Other Models55–65 PSI
D
Purpose:Verify Range operation.

  1. Key off.

  2. Vent vehicle air supply tanks.

    Caution
    Vehicle air tanks may have air stored at pressures in excess of 100 PSI. Failure to vent air tanks may cause personal injury.

  3. Install a 0–100 PSI air pressure gauge into each of the range cover diagnostic ports (L and H).

    Caution
    Use care when removing the test port pipe plugs. If air pressure is present, the plug can become a projectile during removal. When removing the L diagnostic port plug or H diagnostic port plug, pressure can be shut off by selecting the opposite range mode. If removing the F plug, exhaust the air to the module inlet.
    _Graphics/Raster/TRTS0940_FC41 Step D Image.png

  4. Key on with engine running.

  5. Allow air pressure to build to governor cut off.

  6. Key on with engine off.

    Caution
    Verify engine is off before continuing.

  7. Depress and hold Service Brake, select Reverse mode, Low Range, on shift device. Record pressure gauge readings in table.

    • For LAS/VAS/MHP/VHP models: Low Range - Reverse 1 (R1)
    • For VCS/VMS/MXP/VXP/LSE models: Low Range - Reverse 1 or 2 (R1 or R2)

  8. Depress and hold Service Brake, select upshift button on shift device to engage next Reverse gear, High Range. Record pressure gauge readings in table.

    • For LAS/VAS/MHP/VHP models: High Range - Reverse 2 (R2)
    • For VCS/VMS/MXP/VXP/LSE models: High Range - Reverse 3 (R3)

    Note: If Maximum Reverse Gear is set to less than R2 or R3, connect ServiceRanger, Go To Configuration, select Gear. From Maximum Reverse Gear New Value drop down, select R2 or R3 based on model. Select Apply and follow on-screen prompts.

    Note: Pressure change should be immediately reflected on gauges.

    _Graphics/LineArt/PBSC.png

  9. Depress Service Brake, select Neutral on shift device and verify transmission achieves Neutral using gear display.

    Note: If Maximum Reverse Gear was changed, connect ServiceRanger, Go To Configuration, select Gear. From Maximum Reverse Gear New Value drop down, select customer’s original setting. Select Apply and follow on-screen prompts.

  10. Compare reading(s) in table.

ModelModeRangeReading
ReverseRL PortRH PortRL PortRH Port
LAS/VASR175-85 PSI0 PSI
R20 PSI75-85 PSI
MHP/VHPR155-65 PSI0 PSI
R20 PSI55-65 PSI
VCS/VMS/MXP/VXP/LSER1 and R255-65 PSI0 PSI
R30 PSI55-65 PSI
E
Purpose:Verify mechanical condition of Range Cylinder Cover.

  1. Key off.

  2. Vent vehicle air supply tanks.

    Caution
    Vehicle air tanks may have air stored at pressures in excess of 100 PSI. Failure to vent air tanks may cause personal injury.

  3. Remove Range Cylinder Cover.

  4. Verify Range Cylinder Cover air ports are not obstructed or contaminated. Test for obstructions using shop air to ensure proper air flow.

F
Purpose:Verify condition of internal range system components.

  1. Key off.

  2. Vent vehicle air supply tanks.

    Caution
    Vehicle air tanks may have air stored at pressures in excess of 100 PSI. Failure to vent air tanks may cause personal injury.

  3. Disassemble Range Cylinder and components.

  4. Inspect components for damage or contamination, specifically the Piston o-rings and Range Solenoid Valve.

  5. Inspect Range Cylinder and ensure cylinder has a light coating of lube and is free from rust, corrosion or oil.

  • If components are in proper condition, Go to Step G

  • If components show signs of rust, corrosion or oil, or damage is found, overhaul Range Cylinder LAS/VAS Model, replace Range Valve and resolve contamination issues with vehicle air system. Go to Step G

    Note: Rust and moisture may cause premature failure in air system components.

G
Purpose:Verify operation of range system.

  1. Test drive vehicle and ensure that range system works as intended. Operate the vehicle in scenarios that require range shifts to be made.

  • If the vehicle does not properly complete range shifts, Go to Step H

  • If the vehicle completes range shifts without issues, Go to Step V

H
Purpose:Verify condition of auxiliary section components.

  1. Inspect the Transmission Tone Wheel for damaged or missing gear teeth.

  2. Drain transmission oil, looking for signs of significant metal fragments in the lubricant. Look for signs of internal damage to the transmission.

  3. Remove auxiliary case from transmission.

  4. Inspect auxiliary case Yoke Bar and Shift Yoke for any signs of damage.

  5. Inspect Range Synchronizer for signs of worn friction material or broken Synchronizer Pins.

  6. Ensure that auxiliary case Output Shaft Bearing and Auxiliary Countershaft Bearings are not damaged or worn.

  • If no damage is found, and the oil level is correct with no significant metal fragments, replace Range Valve. Go to Step V

  • If damage is found, repair or replace auxiliary case components as necessary. Go to Step V

    Note: If the transmission is found to be low on oil, make sure to inspect the main case for damage due to the low lubricant condition.

V
Purpose:Verify repair.

  1. Key off.

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

  3. Key on with engine off.

  4. Clear fault codes using ServiceRanger.

  5. Drive vehicle and attempt to reset the code or duplicate the previous complaint.

  6. Check for fault codes using ServiceRanger.