Code
U1225
PEUGEOT
U — Network/User
Fault: absence of communication with the gyrometer-accelerometer sensor: Data invalid
Views:
UK: 2
EN: 5
RU: 2
AI status
Completed
Completed
100%
Causes
- Open or short in sensor power or ground circuit
- Broken, corroded or loose connector at the sensor
- Damaged CAN/LIN communication wiring or poor termination
- Faulty gyrometer-accelerometer sensor (internal failure)
- Faulty receiving control module (ECU/ABS/ESP) or its software/configuration
- Blown fuse or intermittent battery supply to sensor
Symptoms
- ESP/ABS/stability warning lamp illuminated or flashing
- Traction control and/or ABS disabled messages
- Loss of yaw/roll/acceleration-based driver aids (stability control, emergency assist)
- Intermittent or permanent fault lamp related to airbags or safety systems (in some models)
- Reduced vehicle handling performance or limp mode for safety systems
What to check
- Read and record all stored DTCs from ABS/ESP, instrument cluster and powertrain modules with a capable scan tool
- Check for related U-/B-/C-codes on the vehicle network
- Visually inspect sensor connector and wiring harness for damage, corrosion, water ingress, broken wires or crushed sections
- Check fuses and power supply circuits for the sensor (measure battery voltage at fuse and sensor plug)
- Measure sensor ground continuity to chassis ground
- Monitor CAN bus with a scan tool: confirm the sensor module is present in bus listings (if supported)
Signal parameters
- Sensor power supply: typically 5 V or 3.3 V (verify with manufacturer data)
- Ground:
- CAN idle voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (recessive); dominant pulse levels ~3.5 V (CAN_H) and ~1.5 V (CAN_L)
- CAN differential idle between CAN_H and CAN_L ≈ 0 V; dominant differential ≈ 2 V
- Typical sensor message frequency: 10–100 Hz (vehicle-dependent)
- Expected data near zero at rest: accelerometer ≈ 0 m/s², gyro ≈ 0 °/s (small offsets possible)
Diagnostic algorithm
- Connect a manufacturer-capable scan tool and record U1225 and any other stored faults; note freeze frame and live values
- Attempt clear of codes, then cycle ignition and re-scan to see if fault reappears (helps detect intermittent faults)
- Inspect sensor connector and harness; repair any damaged wires, clean corroded terminals and reseat connector
- Measure supply voltage and ground at the sensor connector with ignition ON (compare to expected values)
- Check continuity from sensor ground to chassis and from power feed to battery/fuse box
- Probe CAN_H and CAN_L at the sensor connector with an oscilloscope while cycling ignition and activating systems; look for missing messages, stuck levels, excessive noise or missing termination
- Verify CAN termination resistance across CAN_H and CAN_L at the network (≈60 ohm). Repair short circuits or opens as required
- If wiring, connectors and bus are good, substitute a known-good sensor (or move the suspect sensor to a known-good harness if possible) to confirm sensor fault
- If a replacement sensor clears the code, perform any required sensor calibration/initialization per manufacturer procedure
- If sensor swap doesn't help, check receiving module (ABS/ESP) for software updates or reprogramming and inspect its connectors/wiring
- Document repairs and clear codes; road test and re-scan to confirm issue resolved
Likely causes
- Connector/terminal corrosion or bent pins at sensor or module
- CAN bus wiring shorted to battery or ground after recent repairs
- Sensor lost power due to blown fuse or poor ground
- Sensor internal failure after impact or exposure to moisture
- Module firmware mismatch or missing sensor configuration
Fault status
Status
Module reports absence of valid communication from gyrometer-accelerometer sensor. Data messages missing, corrupted or not meeting expected format/values. Fault stored when controller cannot validate sensor data.
Repair difficulty: Medium
Diagnostic time: 1-4 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email