U0402moderate severityNetwork
Invalid Data Received from TCM
on 2003 Mazda B2300 2.3L I4 · FWD
What this code means
The data received from the Transmission Control Module is invalid, out of range, or corrupted.
Symptoms
- Transmission shifting issues
- Erratic shift points
- Check Engine Light
- Transmission slip feeling
- Limp mode
Common causes
- TCM software glitch
- CAN bus noise on TCM circuit
- TCM internal failure
- Bad ground connection
- Wiring interference near TCM
Diagnostic steps
- Check TCM for stored codes
- Update TCM software
- Test CAN bus signal quality at TCM
- Inspect TCM ground connections
- Check for wiring damage near TCM
Repair notes
Reprogram TCM. Check CAN bus quality and TCM ground connections.
Other Network codes on this vehicle
U0001
High Speed CAN Communication Bus
U0002
High Speed CAN Communication Bus Performance
U0003
High Speed CAN Communication Bus (+) Open
U0004
High Speed CAN Communication Bus (+) Low
U0005
High Speed CAN Communication Bus (+) High
U0006
High Speed CAN Communication Bus (-) Open
U0007
High Speed CAN Communication Bus (-) Low
U0008
High Speed CAN Communication Bus (-) High
U0009
High Speed CAN Communication Bus Shorted Together
U0010
Medium Speed CAN Communication Bus