B1596
FR impact sensor open
Causes
- Open or broken wiring between FR impact sensor and SRS ECU
- Corroded, loose, or damaged connector at the FR impact sensor
- Failed FR impact sensor (internal open)
- Poor ground or power supply to the sensor circuit
- Water intrusion or physical damage (collision repair, seat removal)
- Faulty SRS control module or internal module connector fault
Symptoms
- SRS/Airbag warning lamp illuminated on dash
- Possible supplemental restraint system disabled — airbags/pretensioners may be inhibited
- Fault stored in SRS module (may prevent vehicle from passing safety inspection)
- Related SRS codes may be present
What to check
- Read SRS module memory with a capable scan tool; note freeze frame and related codes
- Visual inspection of FR impact sensor, connector, and harness for damage, corrosion, or moisture
- Wiggle test connectors and wiring while monitoring for changes in stored codes or live data
- Verify vehicle battery voltage and SRS ECU power/ground circuits
- Measure continuity/resistance of the sensor circuit to the SRS ECU (compare to service manual)
- Inspect for recent body repairs or seat removal that could have disturbed wiring
Signal parameters
- Circuit condition expected: continuity between sensor pins and SRS ECU (no open circuit)
- Fault indicates an open circuit (infinite or very high resistance) on the FR impact sensor wiring or within the sensor
- Some systems use a low-voltage sensor output or switch; consult manufacturer data for exact resistance/voltages
Diagnostic algorithm
- Retrieve and record all SRS codes and freeze-frame data using a suitable scan tool. Check for related codes (other impact sensors, ECU faults).
- Disconnect negative battery terminal and wait per vehicle procedures to disable SRS before handling connectors or removing trim.
- Perform a visual inspection of the FR impact sensor, mounting area, connector and wiring harness for damage, corrosion, moisture, or loose pins.
- Reconnect battery and back-probe the sensor connector; measure continuity between the sensor pin(s) and the SRS ECU connector. Confirm presence of proper reference power/ground per factory procedures.
- If open circuit is confirmed, trace wiring from sensor to ECU, repairing broken wires, pins, or corroded connectors. Repair using solder/crimp and heat-shrink or OEM-style terminals as required.
- If wiring and connector are good, replace the FR impact sensor with a known-good/new unit following manufacturer replacement and calibration procedures.
- After repair or replacement, clear SRS codes, perform the SRS self-check with the scan tool, and verify the warning lamp extinguishes and no new codes return.
- If fault persists, inspect SRS ECU connectors and grounds; consider ECU fault and consult manufacturer diagnostic procedures or dealer-level support.
Likely causes
- Damaged or disconnected connector at the FR impact sensor (most common)
- Broken wire due to chafing or seat/trim removal
- Failed impact sensor hardware
Fault status
Similar codes
Manual library for MITSUBISHI
Browse 406 MITSUBISHI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
MITSUBISHI
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MITSUBISHI: 2024
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Outlander
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- SE Special Edition, AWD
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Outlander PHEV
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MITSUBISHI: 2022
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Eclipse Cross
- ES, AWD
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- LE, AWD
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- SEL, AWD
- SEL, FWD
- SEL, FWD
- SEL Special Edition, AWD
- SEL Special Edition, AWD
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- SE Special Edition, AWD
- SE Special Edition, AWD
- SE Special Edition, FWD
- SE Special Edition, FWD
-
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MITSUBISHI: 2021
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MITSUBISHI: 2020
B1596
Service Continuous Codes
Causes
- Open or broken wiring between FR impact sensor and SRS ECU
- Corroded, loose, or damaged connector at the FR impact sensor
- Failed FR impact sensor (internal open)
- Poor ground or power supply to the sensor circuit
- Water intrusion or physical damage (collision repair, seat removal)
- Faulty SRS control module or internal module connector fault
Symptoms
- SRS/Airbag warning lamp illuminated on dash
- Possible supplemental restraint system disabled — airbags/pretensioners may be inhibited
- Fault stored in SRS module (may prevent vehicle from passing safety inspection)
- Related SRS codes may be present
What to check
- Read SRS module memory with a capable scan tool; note freeze frame and related codes
- Visual inspection of FR impact sensor, connector, and harness for damage, corrosion, or moisture
- Wiggle test connectors and wiring while monitoring for changes in stored codes or live data
- Verify vehicle battery voltage and SRS ECU power/ground circuits
- Measure continuity/resistance of the sensor circuit to the SRS ECU (compare to service manual)
- Inspect for recent body repairs or seat removal that could have disturbed wiring
Signal parameters
- Circuit condition expected: continuity between sensor pins and SRS ECU (no open circuit)
- Fault indicates an open circuit (infinite or very high resistance) on the FR impact sensor wiring or within the sensor
- Some systems use a low-voltage sensor output or switch; consult manufacturer data for exact resistance/voltages
Diagnostic algorithm
- Retrieve and record all SRS codes and freeze-frame data using a suitable scan tool. Check for related codes (other impact sensors, ECU faults).
- Disconnect negative battery terminal and wait per vehicle procedures to disable SRS before handling connectors or removing trim.
- Perform a visual inspection of the FR impact sensor, mounting area, connector and wiring harness for damage, corrosion, moisture, or loose pins.
- Reconnect battery and back-probe the sensor connector; measure continuity between the sensor pin(s) and the SRS ECU connector. Confirm presence of proper reference power/ground per factory procedures.
- If open circuit is confirmed, trace wiring from sensor to ECU, repairing broken wires, pins, or corroded connectors. Repair using solder/crimp and heat-shrink or OEM-style terminals as required.
- If wiring and connector are good, replace the FR impact sensor with a known-good/new unit following manufacturer replacement and calibration procedures.
- After repair or replacement, clear SRS codes, perform the SRS self-check with the scan tool, and verify the warning lamp extinguishes and no new codes return.
- If fault persists, inspect SRS ECU connectors and grounds; consider ECU fault and consult manufacturer diagnostic procedures or dealer-level support.
Likely causes
- Damaged or disconnected connector at the FR impact sensor (most common)
- Broken wire due to chafing or seat/trim removal
- Failed impact sensor hardware
Fault status
Similar codes
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