U0404moderate severityNetwork
Invalid Data Received from Gear Shift Module
on 2000 Mazda 626 2.5L V6 · FWD
What this code means
The data received from the gear shift position module is invalid or not within expected range.
Symptoms
- Incorrect gear display
- Shifter position not recognized
- Transmission defaulting to safe mode
- Cannot select some gears
Common causes
- Gear shift sensor fault
- Wiring issue to shift module
- Shift module calibration lost
- CAN bus noise
Diagnostic steps
- Check gear shift module for codes
- Test shift position sensor outputs
- Check CAN bus wiring to shift module
- Recalibrate shift module
- Inspect shift mechanism
Repair notes
Recalibrate or replace gear shift module. Check wiring to shifter assembly.
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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