UltraShift PLUS
TRTS0940 EN-US
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July 2024 - A

Fault Code 29: Remote Throttle Enable

J1587: MID 130 SID 372 FMI 4, 5

J1939: SA 3 SPN 969 FMI 4, 5

Overview

The UltraShift PLUS transmission is equipped with a relay circuit that allows the throttle of the engine to be located in a remote location. The relay and associated wiring are installed by the OEM. Fault Code 29 sets when the Transmission Electronic Control Unit (TECU) detects an open or a shorted condition in the wiring between the TECU and the relay.

Detection

The TECU monitors the remote throttle enable circuit for opens or shorts. If either condition is present for 1 second or greater, the fault is set Active.

Conditions to Set Fault Code Active

FMI 4 – Voltage Below Normal or Shorted Low: TECU detects a short to ground in the circuit.

FMI 5 – Current Below Normal or Open Circuit: TECU detects an open circuit or excessive resistance in the circuit.

Fallback

Remote throttle will not function.

Conditions to Set Fault Code Inactive

All FMIs: Short or open condition is not detected by the TECU for 2 seconds.

Possible Causes

FMI 4, 5

  • Vehicle Harness
    • Bent, spread, loose or corroded terminals
    • Wiring shorted to ground or open
  • Remote Throttle Relay
    • Internal failure
  • TECU
    • Internal failure

Component Identification

_Graphics/LineArt/TRTS0940_FC17-29_ID1.png

1. 38-Way Vehicle Harness Connector

2. Transmission Electronic Control Unit (TECU)

3. 5-Way Start Enable Relay Socket

_Graphics/LineArt/TRTS0940_FC29_Wiring.png

1. Transmission Electronic Control Unit (TECU)

2. 38-Way Vehicle Harness Connector

3. 5-Way Remote Throttle Enable Relay Socket

4. 5-Way Remote Throttle Enable Relay

_Graphics/LineArt/Wiring-Key-EPS.png

Fault Code 29 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 29 is Active, Go to Step C

  • If Fault Code 29 is Inactive and there are other Active fault codes, troubleshoot all Active fault codes first.

  • If Fault Code 29 is Inactive, Go to Step B

B
Purpose:Use Product Diagnostic (PD) Mode to locate intermittent failures.

  1. Set parking brake and chock wheels.

  2. Place transmission in PD Mode. See more about Product Diagnostic (PD) Mode.

    Note: Transmission does not enter PD Mode when Active fault codes exist.

    _Common/_Graphics/PD_GearDisplay.png

  3. Wiggle Vehicle Harness wiring and connections between TECU and Remote Throttle Relay.

    Note: Wiring from the Remote Throttle Relay to TECU is OEM proprietary. Refer to OEM guidelines for proper repair or replacement procedures and proper wiring schematics and pin out locations.

  4. Exit PD Mode by powering down.

    Notice
    Allow 2–3 minutes for the TECU to perform a complete power-down sequence before proceeding.

  • If any fault became Active while wiggling wires in the system, refer to OEM guidelines for repair or replacement of wiring between TECU and Remote Throttle Relay. Go to Step V

  • If no fault codes became Active, Go to Step C

C
Purpose:Inspect relay wiring and socket condition.

  1. Key off.

  2. Remove Remote Throttle Relay from socket.

  3. Inspect Remote Throttle Relay Socket and wiring for damage or bent, spread, corroded or loose terminals.

  • If no issues are found, Go to Step D

  • If any issues are present, refer to OEM guidelines for repair or replacement of wiring of Remote Throttle Enable Relay circuit. Go to Step V

D
Purpose:Verify power supply to relay.

  1. Key on with engine off.

  2. Measure voltage between Remote Throttle Relay socket Pin 86 (power) and Pin 85 (ground). Record reading(s) in table.

    _Graphics/LineArt/TRTS0940_FC29_RelayPin86andGround.png

  3. Compare reading(s) in table.

  • If readings are out of range, Go to Step E

  • If readings are in range, refer to OEM guidelines for replacement of the Remote Throttle Relay. Go to Step V

PinsRangeReading(s)
86 to 85Within 1.5 V of Battery Voltage
E
Purpose:Verify continuity of Remote Throttle Relay Circuit wiring between TECU and the relay.

  1. Key off.

  2. Disconnect 38-Way Vehicle Harness Connector from TECU.

  3. Disconnect Remote Throttle Relay from socket.

  4. Measure resistance between 38-Way Connector Pin 24 and Relay Socket Pin 85. Record reading(s) in table.

    _Graphics/LineArt/TRTS0940_FC29_RelayPin86andVPin24.png

  5. Compare reading(s) in table.

PinsRangeReading(s)
24 to 850–0.3 ohms
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.