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Home / DTC / B1357 — Ignition on circuit short to positive

B1357 — Ignition on circuit short to positive

Detailed page for trouble code B1357.

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22,491specific
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Code

B1357

ALFA ROMEO B — Body

Ignition on circuit short to positive

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

Causes

  • Wiring short where ignition-switched wire contacts a constant +12V feed
  • Chafed or pinched harness contacting battery/ignition power source
  • Corroded or bent connector pins causing unintended power feed
  • Aftermarket accessory incorrectly wired to constant power
  • Faulty ignition switch or ignition relay stuck closed
  • Failed control module reporting erroneous input

Symptoms

  • Malfunction indicator(s) or body module warning lamp(s) illuminated
  • Intermittent or no crank/engine start issues (if related to starter/ignition feed)
  • Electrical accessories behaving incorrectly (powered when key off)
  • Battery drain when vehicle is off
  • DTC stored in body/control modules

What to check

  • Read and record freeze frame data and all stored codes with a scan tool
  • Visually inspect wiring and connectors on ignition-switched circuit and related modules
  • Check for aftermarket accessories or recent repairs in affected circuits
  • Measure voltage at suspect circuit with ignition OFF and ON
  • Inspect fuses and relays for correct rating and operation
  • Wiggle-test harnesses with module connected while monitoring voltage/codes (careful to avoid shorts)

Signal parameters

  • Expected: Ignition-switched circuit voltage ~0 V with ignition OFF; ~11–14 V with ignition ON
  • Fault condition: ~11–14 V present on ignition-switched circuit while ignition OFF (indicates short to positive/back-feed)
  • Continuity: Low resistance (< 1–2 ohms) between ignition feed and battery positive only when ignition ON; back-feed will show continuity with ignition OFF
  • Current: Increased parasitic draw on battery when vehicle is off if short/back-feed present

Diagnostic algorithm

  1. Use a scan tool to confirm B1357 is set and note freeze frame/conditions. Clear the code and attempt to reproduce.
  2. Obtain the vehicle wiring diagram for the ignition-switched circuit(s) and identify all modules, relays, fuses and splice points on that circuit.
  3. With ignition OFF, measure voltage at the suspected ignition circuit at module connector and at harness splice points. A steady ~12 V with key OFF indicates back-feed/short to positive.
  4. Visually inspect and flex harnesses along route for chafing, pin damage or repairs. Pay attention to areas near bulkheads, sharp edges and moving components.
  5. Disconnect loads one at a time (modules, relays, aftermarket devices) while monitoring the circuit voltage to isolate the source of the back-feed.
  6. If isolation points to a harness section, perform continuity/short-to-power tests: disconnect battery negative before handling wires, then use an ohmmeter to check for unintended continuity to battery positive with ignition off.
  7. Inspect and repair damaged wiring, replace corroded/mis-seated connectors or faulty relays/ignition switch as required. Replace control module only if confirmed not caused by harness or external back-feed.
  8. Reconnect battery, clear codes, and verify fault does not return during multiple key cycles and after road test or owner-use simulation.
  9. Safety note: disconnect battery before performing wiring repairs and avoid creating shorts when probing connectors.

Likely causes

  • Damaged/chafed harness where ignition circuit touches a constant +12V conductor
  • Connector pin mis-seated/corroded providing back-feed
  • Aftermarket device tapped into constant power instead of switched ignition
  • Faulty ignition relay or switch

Fault status

⚠️ Status
Ignition ON circuit short to positive detected — ignition-switched supply is being back-fed or shorted to battery positive. Repair wiring/connector/relay as required.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

B1356 B1358 B1320 B1399 U0100 U0121
89

Browse 89 ALFA ROMEO manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

ALFA ROMEO

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Code

B1357

FIAT B — Body

Ignition on circuit short to positive

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

Causes

  • Wiring short where ignition-switched wire contacts a constant +12V feed
  • Chafed or pinched harness contacting battery/ignition power source
  • Corroded or bent connector pins causing unintended power feed
  • Aftermarket accessory incorrectly wired to constant power
  • Faulty ignition switch or ignition relay stuck closed
  • Failed control module reporting erroneous input

Symptoms

  • Malfunction indicator(s) or body module warning lamp(s) illuminated
  • Intermittent or no crank/engine start issues (if related to starter/ignition feed)
  • Electrical accessories behaving incorrectly (powered when key off)
  • Battery drain when vehicle is off
  • DTC stored in body/control modules

What to check

  • Read and record freeze frame data and all stored codes with a scan tool
  • Visually inspect wiring and connectors on ignition-switched circuit and related modules
  • Check for aftermarket accessories or recent repairs in affected circuits
  • Measure voltage at suspect circuit with ignition OFF and ON
  • Inspect fuses and relays for correct rating and operation
  • Wiggle-test harnesses with module connected while monitoring voltage/codes (careful to avoid shorts)

Signal parameters

  • Expected: Ignition-switched circuit voltage ~0 V with ignition OFF; ~11–14 V with ignition ON
  • Fault condition: ~11–14 V present on ignition-switched circuit while ignition OFF (indicates short to positive/back-feed)
  • Continuity: Low resistance (< 1–2 ohms) between ignition feed and battery positive only when ignition ON; back-feed will show continuity with ignition OFF
  • Current: Increased parasitic draw on battery when vehicle is off if short/back-feed present

Diagnostic algorithm

  1. Use a scan tool to confirm B1357 is set and note freeze frame/conditions. Clear the code and attempt to reproduce.
  2. Obtain the vehicle wiring diagram for the ignition-switched circuit(s) and identify all modules, relays, fuses and splice points on that circuit.
  3. With ignition OFF, measure voltage at the suspected ignition circuit at module connector and at harness splice points. A steady ~12 V with key OFF indicates back-feed/short to positive.
  4. Visually inspect and flex harnesses along route for chafing, pin damage or repairs. Pay attention to areas near bulkheads, sharp edges and moving components.
  5. Disconnect loads one at a time (modules, relays, aftermarket devices) while monitoring the circuit voltage to isolate the source of the back-feed.
  6. If isolation points to a harness section, perform continuity/short-to-power tests: disconnect battery negative before handling wires, then use an ohmmeter to check for unintended continuity to battery positive with ignition off.
  7. Inspect and repair damaged wiring, replace corroded/mis-seated connectors or faulty relays/ignition switch as required. Replace control module only if confirmed not caused by harness or external back-feed.
  8. Reconnect battery, clear codes, and verify fault does not return during multiple key cycles and after road test or owner-use simulation.
  9. Safety note: disconnect battery before performing wiring repairs and avoid creating shorts when probing connectors.

Likely causes

  • Damaged/chafed harness where ignition circuit touches a constant +12V conductor
  • Connector pin mis-seated/corroded providing back-feed
  • Aftermarket device tapped into constant power instead of switched ignition
  • Faulty ignition relay or switch

Fault status

⚠️ Status
Ignition ON circuit short to positive detected — ignition-switched supply is being back-fed or shorted to battery positive. Repair wiring/connector/relay as required.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

B1356 B1358 B1320 B1399 U0100 U0121
Repair manuals

Manual library for FIAT

26

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FIAT

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Code

B1357

LAND ROVER B — Body

Right front - Foot shock absorber motor

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

Causes

  • Wiring short where ignition-switched wire contacts a constant +12V feed
  • Chafed or pinched harness contacting battery/ignition power source
  • Corroded or bent connector pins causing unintended power feed
  • Aftermarket accessory incorrectly wired to constant power
  • Faulty ignition switch or ignition relay stuck closed
  • Failed control module reporting erroneous input

Symptoms

  • Malfunction indicator(s) or body module warning lamp(s) illuminated
  • Intermittent or no crank/engine start issues (if related to starter/ignition feed)
  • Electrical accessories behaving incorrectly (powered when key off)
  • Battery drain when vehicle is off
  • DTC stored in body/control modules

What to check

  • Read and record freeze frame data and all stored codes with a scan tool
  • Visually inspect wiring and connectors on ignition-switched circuit and related modules
  • Check for aftermarket accessories or recent repairs in affected circuits
  • Measure voltage at suspect circuit with ignition OFF and ON
  • Inspect fuses and relays for correct rating and operation
  • Wiggle-test harnesses with module connected while monitoring voltage/codes (careful to avoid shorts)

Signal parameters

  • Expected: Ignition-switched circuit voltage ~0 V with ignition OFF; ~11–14 V with ignition ON
  • Fault condition: ~11–14 V present on ignition-switched circuit while ignition OFF (indicates short to positive/back-feed)
  • Continuity: Low resistance (< 1–2 ohms) between ignition feed and battery positive only when ignition ON; back-feed will show continuity with ignition OFF
  • Current: Increased parasitic draw on battery when vehicle is off if short/back-feed present

Diagnostic algorithm

  1. Use a scan tool to confirm B1357 is set and note freeze frame/conditions. Clear the code and attempt to reproduce.
  2. Obtain the vehicle wiring diagram for the ignition-switched circuit(s) and identify all modules, relays, fuses and splice points on that circuit.
  3. With ignition OFF, measure voltage at the suspected ignition circuit at module connector and at harness splice points. A steady ~12 V with key OFF indicates back-feed/short to positive.
  4. Visually inspect and flex harnesses along route for chafing, pin damage or repairs. Pay attention to areas near bulkheads, sharp edges and moving components.
  5. Disconnect loads one at a time (modules, relays, aftermarket devices) while monitoring the circuit voltage to isolate the source of the back-feed.
  6. If isolation points to a harness section, perform continuity/short-to-power tests: disconnect battery negative before handling wires, then use an ohmmeter to check for unintended continuity to battery positive with ignition off.
  7. Inspect and repair damaged wiring, replace corroded/mis-seated connectors or faulty relays/ignition switch as required. Replace control module only if confirmed not caused by harness or external back-feed.
  8. Reconnect battery, clear codes, and verify fault does not return during multiple key cycles and after road test or owner-use simulation.
  9. Safety note: disconnect battery before performing wiring repairs and avoid creating shorts when probing connectors.

Likely causes

  • Damaged/chafed harness where ignition circuit touches a constant +12V conductor
  • Connector pin mis-seated/corroded providing back-feed
  • Aftermarket device tapped into constant power instead of switched ignition
  • Faulty ignition relay or switch

Fault status

⚠️ Status
Ignition ON circuit short to positive detected — ignition-switched supply is being back-fed or shorted to battery positive. Repair wiring/connector/relay as required.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

B1356 B1358 B1320 B1399 U0100 U0121
320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
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Code

B1357

Other B — Body

Ignition Run Circuit Short To Battery

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

Causes

  • Wiring short where ignition-switched wire contacts a constant +12V feed
  • Chafed or pinched harness contacting battery/ignition power source
  • Corroded or bent connector pins causing unintended power feed
  • Aftermarket accessory incorrectly wired to constant power
  • Faulty ignition switch or ignition relay stuck closed
  • Failed control module reporting erroneous input

Symptoms

  • Malfunction indicator(s) or body module warning lamp(s) illuminated
  • Intermittent or no crank/engine start issues (if related to starter/ignition feed)
  • Electrical accessories behaving incorrectly (powered when key off)
  • Battery drain when vehicle is off
  • DTC stored in body/control modules

What to check

  • Read and record freeze frame data and all stored codes with a scan tool
  • Visually inspect wiring and connectors on ignition-switched circuit and related modules
  • Check for aftermarket accessories or recent repairs in affected circuits
  • Measure voltage at suspect circuit with ignition OFF and ON
  • Inspect fuses and relays for correct rating and operation
  • Wiggle-test harnesses with module connected while monitoring voltage/codes (careful to avoid shorts)

Signal parameters

  • Expected: Ignition-switched circuit voltage ~0 V with ignition OFF; ~11–14 V with ignition ON
  • Fault condition: ~11–14 V present on ignition-switched circuit while ignition OFF (indicates short to positive/back-feed)
  • Continuity: Low resistance (< 1–2 ohms) between ignition feed and battery positive only when ignition ON; back-feed will show continuity with ignition OFF
  • Current: Increased parasitic draw on battery when vehicle is off if short/back-feed present

Diagnostic algorithm

  1. Use a scan tool to confirm B1357 is set and note freeze frame/conditions. Clear the code and attempt to reproduce.
  2. Obtain the vehicle wiring diagram for the ignition-switched circuit(s) and identify all modules, relays, fuses and splice points on that circuit.
  3. With ignition OFF, measure voltage at the suspected ignition circuit at module connector and at harness splice points. A steady ~12 V with key OFF indicates back-feed/short to positive.
  4. Visually inspect and flex harnesses along route for chafing, pin damage or repairs. Pay attention to areas near bulkheads, sharp edges and moving components.
  5. Disconnect loads one at a time (modules, relays, aftermarket devices) while monitoring the circuit voltage to isolate the source of the back-feed.
  6. If isolation points to a harness section, perform continuity/short-to-power tests: disconnect battery negative before handling wires, then use an ohmmeter to check for unintended continuity to battery positive with ignition off.
  7. Inspect and repair damaged wiring, replace corroded/mis-seated connectors or faulty relays/ignition switch as required. Replace control module only if confirmed not caused by harness or external back-feed.
  8. Reconnect battery, clear codes, and verify fault does not return during multiple key cycles and after road test or owner-use simulation.
  9. Safety note: disconnect battery before performing wiring repairs and avoid creating shorts when probing connectors.

Likely causes

  • Damaged/chafed harness where ignition circuit touches a constant +12V conductor
  • Connector pin mis-seated/corroded providing back-feed
  • Aftermarket device tapped into constant power instead of switched ignition
  • Faulty ignition relay or switch

Fault status

⚠️ Status
Ignition ON circuit short to positive detected — ignition-switched supply is being back-fed or shorted to battery positive. Repair wiring/connector/relay as required.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

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