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Home / DTC / B2354 — Ignition power supply (high)

B2354 — Ignition power supply (high)

Detailed page for trouble code B2354.

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Code

B2354

MITSUBISHI B — Body

Ignition power supply (high)

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

Causes

  • Vehicle electrical system overvoltage (alternator/regulator fault)
  • Short or conductive contamination in ignition power feed (voltage feed tied to another source)
  • Faulty ignition switch or ignition feed relay stuck closed
  • Poor or corroded connector/ground at the control module or ignition circuit
  • Aftermarket electrical accessories incorrectly wired to ignition feed
  • Internal failure in the control module (input circuit damage or sensor fault)

Symptoms

  • Malfunction Indicator Lamp (MIL) or warning lamp illuminated
  • Electrical accessories may behave erratically (instruments, HVAC, radio)
  • Vehicle may have no-start or intermittent starting issues
  • Battery draining or unusual charging system behavior
  • Other modules reporting communication errors or related DTCs

What to check

  • Scan vehicle to confirm B2354 and note any additional DTCs or freeze-frame data
  • Visually inspect battery, alternator, wiring harnesses and ignition switch for damage or aftermarket taps
  • Check fuses and relays related to ignition power feed and module power
  • Measure battery/resting voltage and voltage at the ignition supply terminal at key-off, key-on, and engine-running
  • Measure alternator output and check for overcharging across RPM range
  • Inspect connectors at the affected module for corrosion, bent pins, or water ingress

Signal parameters

  • Battery/rest voltage (key off): typically ~12.0–12.8 V
  • Ignition feed voltage (key ON, engine off): should be near battery voltage, typically 12–14.8 V
  • Charging system running voltage (engine running): typically 13.5–14.8 V
  • High condition threshold: values consistently above ~15–16 V indicate overvoltage; briefly exceeding normal range during start/charge events may be possible but should be investigated

Diagnostic algorithm

  1. Read and record DTCs, freeze-frame data and clear codes. See if B2354 returns immediately or only under certain conditions.
  2. Visually inspect battery, alternator, wiring harness near ignition switch and control module for damage, melted insulation, or aftermarket splices.
  3. With a reliable DMM, measure battery voltage. Then measure voltage at the module's ignition feed pin/narrow terminal with key OFF, key ON, and engine RUNNING. Compare to battery voltage.
  4. Test alternator output: measure charging voltage at battery with engine at idle and at ~2000–3000 rpm. Verify voltage regulator operation and look for voltages above 15 V.
  5. Inspect and test ignition switch and ignition-related relays for stuck contacts or abnormal behavior. Wiggle test wiring while monitoring voltage for intermittent jumps.
  6. Disconnect any recently added aftermarket accessories tied to the ignition feed and re-check voltages/codes.
  7. Repair any wiring faults, corroded connectors, blown fuses, or faulty relays. Replace faulty voltage regulator/alternator if overcharging is confirmed.
  8. After repairs, clear codes and perform a road/operation test to confirm the fault does not return. If the wiring and charging system check good and the code persists, consider testing or replacing the affected control module per manufacturer procedures.
  9. Safety note: Before performing repairs on wiring or modules, isolate battery power where required and follow vehicle manufacturer battery disconnect procedures.

Likely causes

  • Alternator voltage regulator failing and producing excessive output
  • Short to a higher-voltage source on the ignition feed (pinched harness, incorrect jump-start wiring)
  • Faulty ignition switch providing constant higher-than-expected voltage
  • Corroded connector causing intermittent/high readings at the module input
  • Module input stage damaged by a previous overvoltage event

Fault status

⚠️ Status
Ignition power supply voltage higher than expected (overvoltage) detected by control module.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

P0563 P0562 P0620 B2350 B2355
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

B2354

Other B — Body

Driver Mirror Horizontal / Vertical Feedback Potentiometer Circuit Open

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

Causes

  • Vehicle electrical system overvoltage (alternator/regulator fault)
  • Short or conductive contamination in ignition power feed (voltage feed tied to another source)
  • Faulty ignition switch or ignition feed relay stuck closed
  • Poor or corroded connector/ground at the control module or ignition circuit
  • Aftermarket electrical accessories incorrectly wired to ignition feed
  • Internal failure in the control module (input circuit damage or sensor fault)

Symptoms

  • Malfunction Indicator Lamp (MIL) or warning lamp illuminated
  • Electrical accessories may behave erratically (instruments, HVAC, radio)
  • Vehicle may have no-start or intermittent starting issues
  • Battery draining or unusual charging system behavior
  • Other modules reporting communication errors or related DTCs

What to check

  • Scan vehicle to confirm B2354 and note any additional DTCs or freeze-frame data
  • Visually inspect battery, alternator, wiring harnesses and ignition switch for damage or aftermarket taps
  • Check fuses and relays related to ignition power feed and module power
  • Measure battery/resting voltage and voltage at the ignition supply terminal at key-off, key-on, and engine-running
  • Measure alternator output and check for overcharging across RPM range
  • Inspect connectors at the affected module for corrosion, bent pins, or water ingress

Signal parameters

  • Battery/rest voltage (key off): typically ~12.0–12.8 V
  • Ignition feed voltage (key ON, engine off): should be near battery voltage, typically 12–14.8 V
  • Charging system running voltage (engine running): typically 13.5–14.8 V
  • High condition threshold: values consistently above ~15–16 V indicate overvoltage; briefly exceeding normal range during start/charge events may be possible but should be investigated

Diagnostic algorithm

  1. Read and record DTCs, freeze-frame data and clear codes. See if B2354 returns immediately or only under certain conditions.
  2. Visually inspect battery, alternator, wiring harness near ignition switch and control module for damage, melted insulation, or aftermarket splices.
  3. With a reliable DMM, measure battery voltage. Then measure voltage at the module's ignition feed pin/narrow terminal with key OFF, key ON, and engine RUNNING. Compare to battery voltage.
  4. Test alternator output: measure charging voltage at battery with engine at idle and at ~2000–3000 rpm. Verify voltage regulator operation and look for voltages above 15 V.
  5. Inspect and test ignition switch and ignition-related relays for stuck contacts or abnormal behavior. Wiggle test wiring while monitoring voltage for intermittent jumps.
  6. Disconnect any recently added aftermarket accessories tied to the ignition feed and re-check voltages/codes.
  7. Repair any wiring faults, corroded connectors, blown fuses, or faulty relays. Replace faulty voltage regulator/alternator if overcharging is confirmed.
  8. After repairs, clear codes and perform a road/operation test to confirm the fault does not return. If the wiring and charging system check good and the code persists, consider testing or replacing the affected control module per manufacturer procedures.
  9. Safety note: Before performing repairs on wiring or modules, isolate battery power where required and follow vehicle manufacturer battery disconnect procedures.

Likely causes

  • Alternator voltage regulator failing and producing excessive output
  • Short to a higher-voltage source on the ignition feed (pinched harness, incorrect jump-start wiring)
  • Faulty ignition switch providing constant higher-than-expected voltage
  • Corroded connector causing intermittent/high readings at the module input
  • Module input stage damaged by a previous overvoltage event

Fault status

⚠️ Status
Ignition power supply voltage higher than expected (overvoltage) detected by control module.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

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P0563 P0562 P0620 B2350 B2355
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