Fault Code 385: Grade Sensor
J1939: SA 3 SPN 583 FMI 2, 8, 10, 11, 12, 13, 14, 19, 20, 21, 31
Overview
The Transmission Control Module (TCM) is equipped with a Grade Sensor, which calculates vehicle incline. The grade position is used for the Hill Start Aid (HSA) feature and provides information to assist in vehicle launch and shifting. The Grade Sensor is internal to the Transmission Control Module (TCM).
Note: Initial calibration of the Grade Sensor must be completed at the OEM assembly plant or anytime the TCM is replaced. The Grade Sensor Calibration requires ServiceRanger to complete the procedure.
Detection
The TCM monitors the Grade Sensor signal. If the signal is out of range or a system failure is detected, the fault is set active.
Conditions to Set Fault Code Active
FMI 2 – Data Erratic: Grade Sensor signal out of hardware limits. Greater than 100% or less than -100% for 1 second.
FMI 8 – Abnormal Frequency: Grade Sensor signal out of range.
FMI 10 – Abnormal Rate of Change: No change in grade detected over significant distance.
FMI 11 – Failure Mode Not Identifiable: Acceleration up a grade with no accelerator input for 3 seconds.
FMI 12 – Bad Intelligent Device: Grade Sensor self-check failure.
FMI 13 – Out of Calibration: Grade Sensor calibration required.
FMI 14 – Special Instructions: Deceleration down a grade with near maximum accelerator input for 3 seconds.
FMI 19 – Received Network Data in Error: Grade sensor message received in error.
FMI 20 – Data Drifted High: Grade percentage average greater than 25%.
FMI 21 – Data Drifted Low: Grade percentage average less than -25%.
FMI 31 – Condition Exists: Grade Sensor signal out of range. Greater than 50% or less than -50% for 2 seconds.
Fallback
FMI 2, 8, 10, 11, 12, 13, 14, 19, 20, 21, 31:
- Amber warning lamp on
- HSA may be reduced
- Shift strategy may be altered
- Shift and launch quality may degrade
Conditions to Set Fault Code Inactive
FMI 10, 11, 14, 20, 21: Key cycle.
FMI 2, 8, 12, 31: Condition no longer exists.
Possible Causes
FMI 2, 8, 10, 11, 12, 14, 19, 20, 21, 31:
- TCM
- Internal failure
- Software issue
FMI 13:
- Calibration
- Grade Sensor not calibrated
Additional Tools
- Endurant HD Service Manual TRSM0950
Fault Code 385 Troubleshooting
Set vehicle parking brake and chock wheels.
Record the transmission fault codes, FMIs, occurrences, and timestamps from the Service Activity Report created during the Diagnostic Procedure.
If Fault Code 385 FMI 13 is Active, Go to Step B
If Fault Code 385 FMI 13 is Inactive, Grade Sensor Calibration has been completed. Go to Step V
If Fault Code 385 FMI 2, 8, 10, 11, 12, 14, 19, 20, 21, or 31 is Active or Inactive, B
Key off.
Allow TCM to perform a complete power down.
Key on with engine off.
Connect ServiceRanger.
Go to “Service Routines”.
Select "Start" Grade Sensor Calibration and follow on-screen prompts.
If the Grade Sensor Calibration completed with no errors or faults indicated, Go to Step V
If the Grade Sensor Calibration could not be performed or errors or faults are indicated, replace the Transmission Control Module (TCM). Go to Step V
Key off.
Reconnect all connectors and verify that all components are properly installed.
Key on with engine off.
Connect ServiceRanger.
Go to “Fault Codes”.
Select “Clear All Faults”.
Operate vehicle and attempt to reset the fault code or duplicate the previous complaint.
Check for fault codes using ServiceRanger.
If no fault codes set and the vehicle operates properly, test complete.
If Fault Code 385 sets Active during operation, Go to Step A
If a fault code other than 385 sets Active, troubleshoot per the Fault Code Isolation Procedure Index.