Code
C1387
MITSUBISHI
C — Chassis
Lateral G sensor/G performance
Views:
UK: 16
EN: 22
RU: 21
AI status
Completed
Completed
100%
Causes
- Faulty lateral G sensor (internal failure)
- Damaged or corroded wiring/connector to the sensor
- Poor sensor ground or reference voltage
- Sensor incorrectly mounted or mechanically loose
- Sensor requires calibration/zeroing after service
- Intermittent ECU or CAN communication fault
Symptoms
- ABS, ASC or stability control warning lamp illuminated
- Traction/stability control interventions when not needed
- Reduced or disabled stability/traction control functionality
- Stored DTCs related to lateral G, yaw rate, or CAN communication
- Erratic braking or handling in cornering situations
- Live lateral G readings abnormal or not changing with steering
What to check
- Read all stored codes and freeze frame data with a capable scan tool
- Inspect sensor mounting and physical condition for damage or looseness
- Visually inspect sensor connector and wiring for corrosion, breaks, or pin damage
- Check for related codes (yaw rate, roll, pitch sensors, CAN comms)
- Backprobe and verify reference voltage (typically ~5 V), ground, and sensor signal at connector with IGN ON
- Monitor live lateral G sensor values at rest and during low-speed controlled turns
Signal parameters
- Reference supply: typically 5 V reference from ECU (verify for specific model)
- Signal output: analog voltage centered near mid-supply at 0 g (example ~2.5 V on a 5 V system) — should change smoothly with lateral acceleration
- At rest: sensor signal should be stable and close to the expected zero-g voltage
- During lateral motion: signal should vary proportionally and without abrupt steps or dropouts
- No-load noise: very low noise and stable; high noise, open, or fixed voltage indicates fault
Diagnostic algorithm
- Connect a factory-level scan tool and record all stored codes and freeze frame data.
- Visually inspect the lateral G sensor, its bracket, and connectors for damage, looseness, or corrosion.
- With ignition ON (engine off), backprobe the sensor connector: confirm reference voltage, ground continuity, and that the signal voltage is near the expected zero‑g value.
- Clear the code, then monitor live lateral G sensor data while performing slow, controlled left/right turns (in a safe area). Verify signal changes smoothly and is consistent with vehicle motion.
- If signal is stuck, noisy, out of range, or disappears intermittently, perform harness continuity checks between the sensor and ECU; repair any open/shorts or connector issues.
- If harness and power/ground are good but sensor output is incorrect, replace the lateral G sensor.
- After replacement, perform any required sensor calibration/zeroing procedure per manufacturer instructions and perform a road test to verify correct operation.
- If fault persists after sensor replacement and harness is good, investigate ABS/ESP control module or CAN network for faults; check for TSBs or software updates.
Likely causes
- Sensor internal fault or drift
- Open/short in harness to sensor (power, signal, ground)
- Connector corrosion or bent pins at sensor or ECU
- Sensor mounting bolts loose or sensor misaligned
- Lost 5 V reference or unstable reference supply from ECU
- Faulty ABS/ESP control module or software mismatch
Fault status
Status
Lateral G sensor/G performance — lateral acceleration sensor output outside expected range or inconsistent; may disable stability/traction control.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
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