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Home / DTC / B2403 — STL.unit comm.(CRC)

B2403 — STL.unit comm.(CRC)

Detailed page for trouble code B2403.

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Code

B2403

MITSUBISHI B — Body

STL.unit comm.(CRC)

Brand: MITSUBISHI
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Corrupt data on the communication bus (CAN/LIN) resulting in CRC mismatch
  • Faulty or intermittent STL (steering lock / start lock) module
  • Damaged wiring or poor connector pin contact between STL module and network/gateway
  • Low or unstable battery/vehicle voltage during communication
  • Software/firmware mismatch or bug in STL module or gateway
  • Faults in the gateway/body control module that evaluates CRC

Symptoms

  • Malfunction indicator or immobilizer/key warning lamp illuminated
  • Vehicle may not recognize key or may fail to release steering lock
  • No-start or intermittent starting problems related to steering lock/immobilizer
  • Stored B2403 (and possibly other communication-related codes) in scan tool
  • Possible intermittent or permanent loss of remote locking/immobilizer functions

What to check

  • Read and record all stored codes and freeze-frame data with a factory-level scan tool
  • Check battery voltage and charging system (should be stable ~12–14.5 V)
  • Inspect STL module connector and wiring for corrosion, damage, bent pins, or loose terminals
  • Check grounding points and chassis grounds in steering column area
  • Monitor CAN/LIN messages for STL module with a diagnostic tool (message IDs, frequency, CRC status if available)
  • Compare software/firmware versions of STL module and gateway; check for Technical Service Bulletins (TSBs) and available updates

Signal parameters

  • Vehicle battery supply to STL: ~12 V (key off) to ~11–14.5 V (operating)
  • CAN high/low idle voltages: ~2.5 V differential; CANH ~2.5–3.5 V, CANL ~1.5–2.5 V (nominal)
  • Message transmission frequency for STL-related ID (manufacturer-specific)
  • CRC error flag or counter reported by gateway or scan tool (if available)
  • Module presence/acknowledge responses on bus (alive/heartbeat messages)

Diagnostic algorithm

  1. Connect a factory-level or advanced scan tool, read and log all codes and freeze-frame data. Note time/conditions when B2403 was set.
  2. Verify battery voltage and charging system; charge or replace weak battery before further tests.
  3. Visually inspect STL module connector and associated harness for physical damage, corrosion, or moisture. Repair as needed.
  4. Verify power and ground at STL connector with multimeter. Repair poor connections.
  5. With scan tool, monitor the communication bus for the STL module’s messages. Look for missing messages, abnormal frequency, or CRC error counters.
  6. Perform wiggle test of wiring and connectors while watching live data to try to reproduce the CRC error.
  7. If available, compare module firmware versions and consult service information for required updates or reprogramming. Reflash or update modules per manufacturer procedure if mismatch suspected.
  8. If wiring, connectors and software are verified good and fault persists, consider bench or replacement testing of the STL module. Replace module only after confirming cause to avoid unnecessary parts replacement.
  9. After repairs, clear codes and drive/test to confirm the code does not return and all related functions operate normally.

Likely causes

  • Intermittent CAN/LIN wiring/connector fault near steering column
  • Water intrusion or corrosion at STL connector
  • Faulty STL module electronics
  • Vehicle battery low or weak during self-test or coding
  • Recent module replacement or software update left modules with mismatched firmware

Fault status

⚠️ Status
B2403 — STL unit communication CRC error. The gateway/body control module detected a CRC mismatch or corrupt communication from the steering lock/start lock (STL) module. May be set by intermittent or persistent data corruption on the vehicle network or internal STL module fault.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

B2401 B2402 B2404 U0100 U0073
406

Browse 406 MITSUBISHI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

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Code

B2403

Other B — Body

Audio CD/DJ Internal Fault

Brand: Other
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Corrupt data on the communication bus (CAN/LIN) resulting in CRC mismatch
  • Faulty or intermittent STL (steering lock / start lock) module
  • Damaged wiring or poor connector pin contact between STL module and network/gateway
  • Low or unstable battery/vehicle voltage during communication
  • Software/firmware mismatch or bug in STL module or gateway
  • Faults in the gateway/body control module that evaluates CRC

Symptoms

  • Malfunction indicator or immobilizer/key warning lamp illuminated
  • Vehicle may not recognize key or may fail to release steering lock
  • No-start or intermittent starting problems related to steering lock/immobilizer
  • Stored B2403 (and possibly other communication-related codes) in scan tool
  • Possible intermittent or permanent loss of remote locking/immobilizer functions

What to check

  • Read and record all stored codes and freeze-frame data with a factory-level scan tool
  • Check battery voltage and charging system (should be stable ~12–14.5 V)
  • Inspect STL module connector and wiring for corrosion, damage, bent pins, or loose terminals
  • Check grounding points and chassis grounds in steering column area
  • Monitor CAN/LIN messages for STL module with a diagnostic tool (message IDs, frequency, CRC status if available)
  • Compare software/firmware versions of STL module and gateway; check for Technical Service Bulletins (TSBs) and available updates

Signal parameters

  • Vehicle battery supply to STL: ~12 V (key off) to ~11–14.5 V (operating)
  • CAN high/low idle voltages: ~2.5 V differential; CANH ~2.5–3.5 V, CANL ~1.5–2.5 V (nominal)
  • Message transmission frequency for STL-related ID (manufacturer-specific)
  • CRC error flag or counter reported by gateway or scan tool (if available)
  • Module presence/acknowledge responses on bus (alive/heartbeat messages)

Diagnostic algorithm

  1. Connect a factory-level or advanced scan tool, read and log all codes and freeze-frame data. Note time/conditions when B2403 was set.
  2. Verify battery voltage and charging system; charge or replace weak battery before further tests.
  3. Visually inspect STL module connector and associated harness for physical damage, corrosion, or moisture. Repair as needed.
  4. Verify power and ground at STL connector with multimeter. Repair poor connections.
  5. With scan tool, monitor the communication bus for the STL module’s messages. Look for missing messages, abnormal frequency, or CRC error counters.
  6. Perform wiggle test of wiring and connectors while watching live data to try to reproduce the CRC error.
  7. If available, compare module firmware versions and consult service information for required updates or reprogramming. Reflash or update modules per manufacturer procedure if mismatch suspected.
  8. If wiring, connectors and software are verified good and fault persists, consider bench or replacement testing of the STL module. Replace module only after confirming cause to avoid unnecessary parts replacement.
  9. After repairs, clear codes and drive/test to confirm the code does not return and all related functions operate normally.

Likely causes

  • Intermittent CAN/LIN wiring/connector fault near steering column
  • Water intrusion or corrosion at STL connector
  • Faulty STL module electronics
  • Vehicle battery low or weak during self-test or coding
  • Recent module replacement or software update left modules with mismatched firmware

Fault status

⚠️ Status
B2403 — STL unit communication CRC error. The gateway/body control module detected a CRC mismatch or corrupt communication from the steering lock/start lock (STL) module. May be set by intermittent or persistent data corruption on the vehicle network or internal STL module fault.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

B2401 B2402 B2404 U0100 U0073
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