U1401-IMPLAUSIBLE ENGINE SPEED SIGNAL RECEIVED
For a complete wiring diagram Refer to Section 8W.
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
- No CAN Bus DTCs present.
- Transmission Range Sensor
- TCC ON/OFF Solenoid
- Input or Output Speed Sensor
Condition two:
No Active DTCs from the following:
- Lost Communication with ECM/PCM
- No CAN Bus DTCs present.
- 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.
| Possible Causes |
| FCM/TIPM CAN BUS DTCS PRESENT |
| ENGINE MODULE DTCS PRESENT |
| TRANSMISSION CONTROL MODULE |
Always perform the CVT Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)
Diagnostic Test
1. CHECK IF THE DTC IS ACTIVEWith the scan tool, read Transmission DTCs.
Is the status Active for this DTC or is the STARTS SINCE SET counter 2 or less?
Yes
- Go To 2
No
- Go To 4
2. CHECK FOR FCM/TIPM CAN BUS DTCS
With the scan tool, read FCM DTCs.
Are there any FCM/TIPM CAN BUS DTCs present?
Yes
- (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING) category and perform the appropriate symptom(s).
- Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)
No
- Go To 3
3. CHECK IF ENGINE DTCS ARE PRESENT
With the scan tool, read engine DTCs.
Are there any engine DTCs present?
Yes
- (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING) category and perform the appropriate symptom(s).
- Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)
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 per the Service Information. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/TRANSMISSION CONTROL MODULE - REMOVAL)
- Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)
4. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires while checking for shorted and open circuits.
Were there any problems found?
Yes
- Repair as necessary.
- Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)
No
- Test Complete.