U1401

U1401-IMPLAUSIBLE ENGINE SPEED SIGNAL RECEIVED

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Transmission Control Module (TCM) receives Engine rpm over the CAN Bus.

- When Monitored:
Ignition on with a system voltage between 9.0 and 16.0 volts.

Time since last TRS change greater than 2.0 seconds.

Condition one:

TCC ON/OFF in the ON position.

No Active DTCs from the following:

- Lost Communication with ECM/PCM
- Step Motor
- TCC ON/OFF Solenoid
- Input or Output Speed Sensor
Condition two:

No Active DTCs from the following:

- Lost Communication with ECM/PCM
- Step Motor

Condition one:

All the below conditions must be present for the period of 5 seconds for the DTC to set:

- Engine speed minus Input speed is greater than 1000 rpm for the period of 5 seconds.
- Engine speed minus Secondary speed estimated ratio is greater than 1000 rpm for the period of 5 seconds.
- Secondary speed multiplied by the estimated ratio minus the primary speed is less than 1000 rpm.
Condition two:

- Engine speed is less than 450 rpm and the Input speed is greater than or equal to 1000 rpm for the period of 20 msec.






Always perform the CVT Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview

1. CHECK IF THE DTC IS ACTIVE
1. With the scan tool, read Transmission DTCs.

Is the status Active or is the Starts Since Set counter 2 or less for this DTC?

Yes

- Go To 2

No

- Go To 4

2. CHECK FOR FCM/TIPM CAN BUS DTCs
1. With the scan tool, read FCM DTCs.

Are there any FCM/TIPM CAN BUS DTCs present?

Yes

- Refer to DTC Based Diagnostics and perform the appropriate diagnostic procedure.
- Perform CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test

No

- Go To 3

3. CHECK IF ENGINE DTCs ARE PRESENT
1. With the scan tool, read engine DTCs.

Are there any engine DTCs present?

Yes

- Refer to DTC Based Diagnostics and perform the appropriate diagnostic procedure.
- Perform CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test

No

- Using the schematics as a guide, check the Transmission Control Module (TCM) pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM.
- Perform CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test

4. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set this DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle the wires while checking for shorted and open circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test

No

- Test Complete.