Transmission Low Air Pressure and/or Clutch Temperature Display Messages

Date: September 17, 2018

Updated: October 2, 2023

Issue Description:

Customers may experience a low transmission air pressure and/or clutch temperature message during low speed maneuvering or stop and go traffic situations.

• Low transmission air pressure message: This issue may be induced by a vehicle air system not functioning properly resulting in the inability to achieve or maintain operating air pressure. Low air pressure may be induced by excessive use or cycling of the service brake, exhausting the vehicle air supply.
• Clutch temperature message: This issue may be induced by “two footing” the service brake and accelerator pedal simultaneously causing the clutch not to fully close, inducing a clutch slip and increasing clutch temperature.

Fault codes that may set during these events:

• Transmission Air Supply Pressure: FC215 SPN 37 FMI 18
• Clutch Temperature: FC815 SPN 5939 FMI 15 and/or 16

Containment/Corrective Action:

Driver recommendations:

• Ensure the vehicle air system is operating per OEM requirements.

• Allow the vehicle air system to reach normal operating range, 99 (106 at the Air Brake Tanks for Navistar) to 130 PSI (6.8 to 9.0 Bar), prior to selecting a gear from neutral.

• Navistar with SW update to:
  • (A4 Controller) 5516062 and/or OEM supplied air line reroute instructions / Transmission normal operating range is 99-130 PSI -or-
  • (A5 Controller) 5516372 / Service Release -or-
  • (A5 Controller) 5516374 / Service Release or greater and/or OEM supplied air line reroute instructions / Transmission normal operating range is 99-130 PSI.

• Avoid “two footing” the service brake and accelerator pedal.

• Avoid using the accelerator pedal to hold the vehicle on a hill - depress and hold the service brake until movement is required.

• During operation on a grade, rely on Hill Start Aid (HSA) when transitioning from the service brake pedal to the accelerator pedal.

• During low speed maneuvering, select the lowest available start gear (1st or R1) and rely on Urge to Move and Creep Mode to assist in moving the vehicle at engine idle without having to apply the accelerator pedal.

Note: For additional information on how to operate the transmission refer to Driver Instructions TRDR0950 and GET 2 KNOW videos.

Recommendations when messages are displayed:

• Low transmission air message - allow the vehicle air system to reach normal operating range (100 PSI or above / 106 at the Air Brake Tanks for Navistar) and then continue operation. For optimal performance, the transmission requires 99 to 130 PSI (6.8 to 9.0 Bar).

• Navistar with SW update to:
  • (A4 Controller) 5516062 and/or OEM supplied air line reroute instructions / Transmission normal operating range is 99-130 PSI -or-
  • (A5 Controller) 5516372 / Production -or-
  • (A5 Controller) 5516374 / Service Release or greater and/or OEM supplied air line reroute instructions / Transmission normal operating range is 99-130 PSI.

Note: Transmission software version 5516024 includes enhancements that prevent Fault Code 215 from setting while transmission is in Neutral mode.

• Non-Navistar Chassis: With software version 5516024 and above, if the driver attempts to select a non-neutral mode before transmission air pressure reaches 80 PSI, the transmission will prevent gear engagement and Fault Code 215 will set Active.
• Navistar Chassis: At initial key on with software version 5516024 and above, if a driver attempts to select a non-neutral mode before transmission air pressure reaches 90 PSI, and the air brake tanks reach 106 PSI, the transmission will prevent gear engagement. The 106 PSI minimum on a Navistar chassis matches the tractor protection valve (OEM Requirement). If chassis air pressure falls below 106 PSI (Key on normal operation) the transmission will continue to shift until a minimum of 75 PSI is reached (see Item A / Degraded Performance).
• Navistar with SW update to:
  • (A4 Controller) 5516062 and/or OEM supplied air line reroute instructions / Transmission normal operating range is 99-130 PSI -or-
  • (A5 Controller) 5516372 / Production -or-
  • (A5 Controller) 5516374 / Service Release or greater and/or OEM supplied air line reroute instructions / Transmission normal operating range is 99-130 PSI.

Update: As a vehicle enhancement Navistar will have work instructions to reroute the airline that feeds the transmission air tank, reference I-Know article IK1300192.

SW update to 5516062 (A4 Controller) or 5516374 (A5 Controller) or greater is also required. The combination of rerouting the air line and a SW update will allow the transmission to obtain a gear from neutral at 95 PSI.

• As of 04/14/2023 Navistar production changed their rerouting of the air line feeding the Endurant Transmission.
• Navistar trucks built from 04/14/2023 to November 2023 will need a SW update to 5516062 (A4 Controller) or 5516374 (A5 Controller / Service Release 10/02/2023) to allow the Endurant Transmission to obtain a gear from neutral at 95 PSI.
• ETA for Navistar production to change to 5516372 SW is November 2023. 5516372 production SW supports the Endurant Transmission logic change.
• After air line reroute and/or SW update, key off, drain primary, secondary, and transmission air tanks. Close air tank drains, restart engine and allow the transmission to “learn” the air system configuration (Transmission Logic / transmission is now tied to the secondary tank) as the compressor builds air pressure.

Air line rerouting and/or SW update to the Endurant Transmission is considered an enhancement / non-warrantable thru Eaton / ECJV / Navistar.

Note: Transmission and Air Brake Tanks can be monitored in SR4 / Data Monitor.

• Clutch temperature message - safely and immediately discontinue the operation that is being performed which is causing the clutch to overheat. Depress and hold the service brake or set vehicle parking brake and idle the engine until the message is no longer indicated and then continue normal operation. Ensure the engine is allowed to idle, shitting off the engine prolongs the condition.

  Note: Transmission software version 5516024 includes enhancements that allow the transmission to continue operation when Fault Code 815 sets. Fallback mode of the Fault Code will still disable some transmission functionality such as launching in a higher start gear and Urge to Move. The driver will continue to be notified of a Clutch Abuse event via a dash message and audible tone. A software update to 5516024 for Fault Code 815 is considered a non-warrantable issue.

Note: If the transmission low air and/or clutch temperature condition no longer exists some OEM displays may require the driver to manually clear the message with older cluster software versions. Refer to OEM guidelines regarding the display message reset procedure.

Navistar is offering a dash cluster software update with 6024 transmission SW update that has changed the warning displays. Reference Navistar iKNow article (IK0800550).

• Transmission Air Supply Low - Least Severe:
  • Requirements to set dash response: Engine Running, Trans Current Gear Neutral, Shift device Neutral, Vehicle Not Moving, and Transmission Air Pressure < 90 PSI or Brake Tank Pressure < 106 PSI.
  • With SW update to 5516062 (A4 Controller) or 5516374 (A5 Controller) or greater and OEM supplied air line reroute instructions / Transmission Air Pressure < 90 PSI or Brake Tank Pressure < 95 PSI.
  • Dash response was: “Transmission Air Pressure Low Warning” with driver acknowledgment now “System Air Pressure Low” and does not require the driver to manually clear the message
• Transmission Air Supply Low - Moderately Severe Level:
  • Requirements to set dash response: Vehicle Stopped, Neutral Mode, Shift Device Not Neutral, and Trans Air Pressure < 90 PSI or Brake Tank Pressure < 106 PSI or Vehicle moving and Trans Air Tank Pressure < 85 PSI or Trans in Non-Neutral Mode and Trans Air Pressure < 85 PSI.
  • With SW update 5516062 (A4 Controller) or 5516374 (A5 Controller) or greater and OEM supplied air line reroute instructions / Transmission Air Pressure < 90 PSI or Brake Tank Pressure < 95 PSI.
  • New dash response “System Air Pressure Low Gear Change Not Allowed”
• Transmission Air Supply Low - Most Severe Level:
  • Requirements to set dash response: Engine Running, Vehicle Moving, and Trans Air Pressure < 75 PSI.
  • New dash response: System Air Pressure Low Transmission Disabled
• Clutch Abuse - Moderately Severe Level:
  • Requirements to set dash response: Clutch plate temperature estimated > 210 C
  • Dash response was: “Clutch Temp High - Function Limited” now “Clutch Temp High”
• Clutch Abuse - Most Severe Level:
  • Requirements to set dash response: Clutch plate temperature estimated > 235 C
  • Dash response was: “Clutch Temp Over Limit Allowed” now “Clutch Overheated Allow Clutch to Cool”

Refer to OEM guidelines regarding the display message reset procedure.

Affected Models/Population:

• Endurant Transmissions

Warranty Information:

Informational only.

Item A:

Endurant Installation Guide link, go to Section 6: Pneumatic System Requirements.

Section 6: Pneumatic System Requirements

Supply Pressure

For optimal performance, the Eaton Endurant transmission requires a nominal air supply operating range between 99 PSI (6.8 bar) and 130 PSI (9.0 bar). Air supply outside this range can result in degraded or complete loss of transmission shift capabilities. The following figure summaries the significant thresholds for various air supply pressures.

The material contained in this bulletin is product improvement information. Eaton Corporation is not committed to, or liable for, canvassing existing products.

Change Log

FSUD: 2651