Fault Code 110: Ignition Voltage

J1939: SA 3 SPN 158 FMI 2

Overview

The Transmission Control Module (TCM) requires a key on battery voltage ignition supply. The Ignition Voltage initiates TCM operation at and during key-on. The Ignition Voltage wiring connects to the TCM through the 20-Way TCM Vehicle Harness Connector.

Detection

The TCM monitors the vehicle’s Ignition Voltage supply. If there is a loss of Ignition Voltage while driving, the fault code is set Active.

Conditions to Set Fault Code Active

FMI 2 – Data Erratic: Ignition Voltage available with output shaft speed less than 10 RPM.

Fallback

FMI 2:

  • Amber warning lamp on
  • Coast Mode and Neutral Coast prohibited
  • Upshifts prohibited
  • Engine communications may not be available
  • If vehicle comes to a stop, TCM will shut down

    Note: Vehicle may have additional fallback modes. Refer to OEM.

Conditions to Set Fault Code Inactive

FMI 2: Ignition Voltage is available with output shaft speed less than 10 RPM.

Possible Causes

FMI 2:

  • Ignition switch keyed off during operation
  • Vehicle components
    • Ignition switch internal failure
  • Vehicle Harness - Ignition Circuit
    • Wiring shorted to ground or open
    • Terminals bent, spread, corroded, or loose

Note: Refer to OEM for troubleshooting a failed system.

Additional Tools

  • None

Component Identification

_Graphics/LineArt/TRTS0960_FC100_ComponentID.png

1. 20-Way TCM Vehicle Harness Connector

2. Transmission Control Module (TCM)

_Graphics/LineArt/TRTS0950_FC110_WiringID.png

1. Transmission Control Module (TCM)

2. 20-Way TCM Vehicle Harness Connector

3. In-line Fuse Holder

4. 10-amp Fuse

_Graphics/LineArt/TRTS0950_Wiring-Key.png

Fault Code 110 Troubleshooting

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

  2. Set vehicle parking brake and chock wheels.

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

    Note: If vehicle comes to a stop, TCM will shut down, and Fault Code 110 will be Inactive.

  • If Fault Code 110 is Inactive and there are other Active vehicle or transmission fault codes, troubleshoot all Active fault codes. Go to Step V

  • If Fault Code 110 FMI 2 is Inactive, Go to Step B

B
Purpose:Verify Ignition voltage supply.
  1. Key on with engine off.

  2. Connect ServiceRanger.

  3. Go To “Data Monitor”.

  4. From “Default Parameter Files” tab, select “Transmission Supplied Voltages”.

  5. Monitor 158 - Battery voltage - switched value. Record reading in table.

  6. Compare reading(s) in table.

  • If readings are out of range, refer to OEM guidelines for repair or replacement of the vehicle's Ignition Voltage supply.

    Note: Some chassis use a power distribution system, inspect all connections.

  • If readings are in range:

    • Vehicle operator may have cycled key off while vehicle was moving. Go to Step V
    • or
    • The intermittent nature of the fault makes it likely there is a wiring problem between vehicle’s Ignition Voltage supply and 20-Way TCM Vehicle Connector. Refer to OEM guidelines for repair or replacement of vehicle's ignition voltage circuit, vehicle harness, and/or 20-Way TCM Vehicle Harness Connector. Go to Step V
ParameterRangeReading(s)
158 - Battery voltage - switched11–15 V
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.