Code
U1203
MITSUBISHI
U — Network/User
Lateral G sensor parity error
Views:
UK: 14
EN: 20
RU: 13
AI status
Completed
Completed
100%
Causes
- Faulty lateral G (accelerometer) sensor
- Intermittent or damaged wiring between sensor and control module
- Poor or corroded electrical connector or ground
- Loss of reference supply or incorrect sensor voltage
- Faulty receiving ECU (ABS/ESP/vehicle dynamics ECU) or internal communications fault
- CAN/bus communication errors or electromagnetic interference
Symptoms
- ESP/traction control/ABS warning lamp illuminated
- Reduced or disabled stability control/traction control functionality
- Stored U1203 (and possibly related U-codes) in ECU
- Possible diagnostic trouble codes related to other inertial sensors
- No obvious drivability symptoms in straight-line, but instability may be present in cornering
What to check
- Read and record DTCs and freeze frame data with a capable scan tool; check pending/historic status
- Verify vehicle battery voltage and charging system stability during test
- Visual inspection of lateral G sensor, mounting, harness, and connectors for damage, corrosion or water intrusion
- Wiggle test harness/connectors while monitoring live sensor data or DTC status
- Measure sensor supply (reference), ground, and output signal with multimeter/oscilloscope
- Check CAN/communication lines for errors, bus voltage levels and continuity
Signal parameters
- Sensor supply/reference: typically ~5 V (verify OEM spec)
- Sensor ground: ~0 V (good low resistance ground)
- Sensor output at 0 g: mid-rail voltage (~2.5 V typical; consult service manual)
- Output change per lateral g: sensor-specific (e.g., several hundred mV/g) — verify OEM data
- CAN bus idle voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (dominant/recessive levels vary); check differential and noise
- Parity/CRC errors: reported by receiving module when packets fail integrity checks
Diagnostic algorithm
- Connect OEM-capable scan tool. Clear codes, then attempt to reproduce. Note if U1203 returns immediately or intermittently.
- Record freeze frame and live lateral G sensor data. Confirm whether sensor output is present and stable at rest (should be near mid-scale voltage).
- Visually inspect sensor and wiring for damage, chafing, corrosion, or loose mounting. Repair any obvious issues.
- With ignition ON, measure sensor reference voltage and ground at the sensor connector. Compare to OEM specs.
- Backprobe sensor output and observe voltage with vehicle stationary and during low-speed lateral input (safe hand-turn or incline) if practical. Use oscilloscope for noise or parity timing problems.
- Perform a wiggle test of harness and connector while monitoring live data and DTC status to find intermittent faults.
- Check CAN/communication lines for errors and continuity. If CAN errors present, trace to source and repair wiring/terminations.
- If wiring and power/ground are correct but data still invalid, swap with a known-good sensor (if available) or replace the lateral G sensor.
- After repair or replacement, clear codes, perform the required auto-calibration or sensor alignment procedure per OEM, then road test to confirm the fault is gone.
- If problem persists, consider module-side fault (ABS/ESP ECU). Check for software updates or reprogramming and consult manufacturer service information.
Likely causes
- Open/short or intermittent wiring at the lateral G sensor connector
- Contaminated/corroded pins or poor connector contact
- Failed lateral G sensor (drifted or internal parity error)
- Low/high sensor supply voltage (battery/ignition supply or sensor reference)
- Module communication fault or need for software update
Fault status
Status
Lateral G sensor parity error — receiving module detected invalid/inconsistent data or parity/CRC failure from the lateral accelerometer. Fault may be stored as active or intermittent and can disable stability functions.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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Code
U1203
Other
U — Network/User
SCP (J1850) Invalid or Missing Data for Windows
Views:
UK: 17
EN: 27
RU: 19
AI status
Completed
Completed
100%
Causes
- Faulty lateral G (accelerometer) sensor
- Intermittent or damaged wiring between sensor and control module
- Poor or corroded electrical connector or ground
- Loss of reference supply or incorrect sensor voltage
- Faulty receiving ECU (ABS/ESP/vehicle dynamics ECU) or internal communications fault
- CAN/bus communication errors or electromagnetic interference
Symptoms
- ESP/traction control/ABS warning lamp illuminated
- Reduced or disabled stability control/traction control functionality
- Stored U1203 (and possibly related U-codes) in ECU
- Possible diagnostic trouble codes related to other inertial sensors
- No obvious drivability symptoms in straight-line, but instability may be present in cornering
What to check
- Read and record DTCs and freeze frame data with a capable scan tool; check pending/historic status
- Verify vehicle battery voltage and charging system stability during test
- Visual inspection of lateral G sensor, mounting, harness, and connectors for damage, corrosion or water intrusion
- Wiggle test harness/connectors while monitoring live sensor data or DTC status
- Measure sensor supply (reference), ground, and output signal with multimeter/oscilloscope
- Check CAN/communication lines for errors, bus voltage levels and continuity
Signal parameters
- Sensor supply/reference: typically ~5 V (verify OEM spec)
- Sensor ground: ~0 V (good low resistance ground)
- Sensor output at 0 g: mid-rail voltage (~2.5 V typical; consult service manual)
- Output change per lateral g: sensor-specific (e.g., several hundred mV/g) — verify OEM data
- CAN bus idle voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (dominant/recessive levels vary); check differential and noise
- Parity/CRC errors: reported by receiving module when packets fail integrity checks
Diagnostic algorithm
- Connect OEM-capable scan tool. Clear codes, then attempt to reproduce. Note if U1203 returns immediately or intermittently.
- Record freeze frame and live lateral G sensor data. Confirm whether sensor output is present and stable at rest (should be near mid-scale voltage).
- Visually inspect sensor and wiring for damage, chafing, corrosion, or loose mounting. Repair any obvious issues.
- With ignition ON, measure sensor reference voltage and ground at the sensor connector. Compare to OEM specs.
- Backprobe sensor output and observe voltage with vehicle stationary and during low-speed lateral input (safe hand-turn or incline) if practical. Use oscilloscope for noise or parity timing problems.
- Perform a wiggle test of harness and connector while monitoring live data and DTC status to find intermittent faults.
- Check CAN/communication lines for errors and continuity. If CAN errors present, trace to source and repair wiring/terminations.
- If wiring and power/ground are correct but data still invalid, swap with a known-good sensor (if available) or replace the lateral G sensor.
- After repair or replacement, clear codes, perform the required auto-calibration or sensor alignment procedure per OEM, then road test to confirm the fault is gone.
- If problem persists, consider module-side fault (ABS/ESP ECU). Check for software updates or reprogramming and consult manufacturer service information.
Likely causes
- Open/short or intermittent wiring at the lateral G sensor connector
- Contaminated/corroded pins or poor connector contact
- Failed lateral G sensor (drifted or internal parity error)
- Low/high sensor supply voltage (battery/ignition supply or sensor reference)
- Module communication fault or need for software update
Fault status
Status
Lateral G sensor parity error — receiving module detected invalid/inconsistent data or parity/CRC failure from the lateral accelerometer. Fault may be stored as active or intermittent and can disable stability functions.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 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
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Send to email